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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2435
Registered: 6-2009
Posted on Monday, 09 October, 2017 - 06:03 am:   Edit PostDelete PostView Post/Check IP

Gentlemen, this thread is a direct follow-on to my original that was entitled, Fuel Injector Cleaner.

Here's the long and short of it all. After giving all the electrical connections to the fuel injectors a good dose of Caig DeOxIt my problem with misfiring on cold startup and at low speeds immediately resolved. The spark plugs were replaced with Bosch Platinum-Ir Fusion plugs as a part of this project.

The fuel injector cleaner may (or may not) be helping, but I believe it is.

I can now only induce a misfire if I am traveling at highway speeds (above 60 MPH) and only if I have taken my foot off the accelerator briefly and need to speed up again with a "moderate push." If I do a very gentle push and very slow acceleration everything is fine. If I floor it everything is fine. Even sometimes when I give the "moderate push" it's fine. The misfire can be felt but it is not triggering the OBD since it does not persist or recur within the window required.

I do not believe this is a spark issue or I should be seeing it at different speeds and different times. I now think it's a fuel issue.

What I am wondering is whether anyone else believes I may, after 21 years and 200K miles, have a fuel injection pressure regulator that is going wonky under a very specific set of conditions and very briefly? It seems to me that when one takes one's foot off the accelerator this causes a pressure drop in the fuel injection system and when one starts accelerating again there would be a brief spike in pressure when the system is ramping up again until stasis is achieved. Since my issue is only occurring during the acceleration phase, never when at any cruising speed, and in a very specific style of accelerating it makes me think this might be the culprit.

My experience with the diagnosis and repair of fuel injection systems is zero. What I think I understand of them is from "book learning" and even that is limited.

Even though this is not on a Rolls-Royce or Bentley, the principles of operation for fuel injection (port fuel injection in this case as opposed to throttle body injection) should be basically the same regardless of make or model.

What are the thoughts of those who have "been there, done that" with the idea of the next part being thrown at this being a fuel pressure regulator?

Brian
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ross kowalski
Grand Master
Username: cdfpw

Post Number: 579
Registered: 11-2015
Posted on Monday, 09 October, 2017 - 01:05 pm:   Edit PostDelete PostView Post/Check IP

Brian,

In your earlier post, you mentioned that it was cylinder 7 having the misfire (code p0307?).

If you are feeling a misfire now it would be helpful to know if it was still a misfire on 7 or on all cylinders or even if it actually is a misfire.

A $3 OBDII BT dongle and the $4 torque app are invaluable in this kind of diagnosis.

If it's still just missing on 7 then that would largely rule out a fuel pressure event.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2438
Registered: 6-2009
Posted on Monday, 09 October, 2017 - 01:49 pm:   Edit PostDelete PostView Post/Check IP

Ross,

I cannot know which cylinder because it is transient enough that it's not being picked up by the computer.

I have little doubt it's a miss, as it feels like it did when it would miss, just not as frequently now (not nearly as frequently now) and it was missing at lower speeds before.

I have a dedicated OBD-II reader as well as Torque Pro and several different ELM OBD-II dongles. None do me any good if the darned thing won't throw a code. I don't see anything really odd in the live data that the Innova 3130 can collect, but perhaps I'm missing something.

Brian, who's now off to bed
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David Gore
Moderator
Username: david_gore

Post Number: 2685
Registered: 4-2003
Posted on Monday, 09 October, 2017 - 02:52 pm:   Edit PostDelete PostView Post/Check IP

Brian,

I know this is a trick from the past but it is useful when electrical "gremlins" are about....

Find an old AM transistor radio, tune it to any part of the reception band where a station cannot be heard, turn the volume up and then bring it close to each HT lead in turn while the engine is idling/revving at a speed consistent with when the hesitation is apparent and listen for pronounced clicks - this will indicate possible insulation/conductor breakdowns in the lead(s) where the clicking is loudest.

I have had the type of hesitation problem you are experienced in the days of points and coils and, more often than not, the problem was intermittent shorting internally/externally in one or more leads.
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Alan Dibley
Frequent User
Username: alsdibley

Post Number: 96
Registered: 10-2009
Posted on Monday, 09 October, 2017 - 06:02 pm:   Edit PostDelete PostView Post/Check IP

The rationale for David's suggestion is that when the foot is applied to the pedal the amount of air admitted to cylinders is increased. This increases the peak pressure in the cylinders at the instant of firing. This demands increased voltage at the plugs before sparking occurs, and if there is an easier path to ground than the spark plug the current will take it. Common routes in RR/B engines with enclosed leads are inside the metal ignition lead covers. If the engine has individual coils on each plug it suggests a faulty spark module.

HTH.

Alan D.
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ross kowalski
Grand Master
Username: cdfpw

Post Number: 581
Registered: 11-2015
Posted on Monday, 09 October, 2017 - 10:37 pm:   Edit PostDelete PostView Post/Check IP

David,

That AM radio test is a pretty clever trick. I bet the click is pretty pronounced when the lead arcs to the antenna. The pie plate dizzy behind the water pump on this motor can give some pretty weird symptoms.

Brian,

You can try the old spray bottle trick. At night spray water on the engine and run it. Bad insulation is pretty easy to see there as sparks.

You might also want to spray the distributor and see if that does anything. Sometimes the insulation on the plug wires is so bad the engine will actually stumble with the water.

Also, I don't remember, did you ever run the fuel pressure on this motor?
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Mark Luft
Prolific User
Username: bentleyman1993

Post Number: 112
Registered: 10-2016
Posted on Tuesday, 10 October, 2017 - 07:22 am:   Edit PostDelete PostView Post/Check IP

Brian, I think you have a intermittent fault with the MAP/MAF sensor. Pressure or air flow.
Just my .02
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1553
Registered: 9-2004
Posted on Tuesday, 10 October, 2017 - 05:01 pm:   Edit PostDelete PostView Post/Check IP

This is like a game of I spy great fun for Brian me thinks.
I go with the jerk under or above the seat, if not caused by a vibration of a mechanical type then I would look towards a carbon resister ht lead failing.
this starts with a cylinder misfire under load in most cases.
The old OBD system in most cases will not throw a code for this type of fault.
Ross, good tip with the water spray.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2440
Registered: 6-2009
Posted on Tuesday, 10 October, 2017 - 11:49 pm:   Edit PostDelete PostView Post/Check IP

No, not great fun. I hate hard to diagnose issues.

Since I haven't succeeded in eliminating the issue and neither has a professional mechanic (who admitted defeat and charged nothing after days of diagnostic work) this is definitely "hard to diagnose." I'm impressed with myself in that having treated the electrical connections to the fuel injectors with Caig DeOxIt helped immensely. Whether it was the product or just unseating and reseating remains an open question, but whatever it is made an incredibly major improvement and left me with this small quirk afterward. I went from initially having the car throw a P0300 (random misfire detected) code at the outset of all this to a more limited P0307 that stayed that way, and with rough running the moment the car was started each and every time, to what I have now, which is 99.5% back to perfectly normal.

The array of options being presented shows just how "hard to diagnose" and although there are definitely things to try, like the water spray, for instance, I may be arriving at the "strategically throw parts at it" stage soon. That's part of the reason for asking opinions from others who've "been there, done that, got the T-shirt."

Brian
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1554
Registered: 9-2004
Posted on Tuesday, 10 October, 2017 - 11:56 pm:   Edit PostDelete PostView Post/Check IP

Ah confirmed miss fire at last!

How was the scope trace did you get a print off and with live data under load?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2442
Registered: 6-2009
Posted on Wednesday, 11 October, 2017 - 12:09 am:   Edit PostDelete PostView Post/Check IP

Patrick,

If you would pay the slightest bit of attention to events as they unfolded, in this case over a couple of threads, you couldn't have missed that this all started with confirmed misfires.

Therein lies your problem, not mine. You simply latch on to what you want to latch on to without any regard to how things leading up to now have transpired.

Brian
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1555
Registered: 9-2004
Posted on Wednesday, 11 October, 2017 - 02:49 am:   Edit PostDelete PostView Post/Check IP

Brian, yes i do but you have only now stated that you had codes referring to no 7 cylinder and confirmed MISSFIRE.
So how was the trace and live data under load?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2443
Registered: 6-2009
Posted on Wednesday, 11 October, 2017 - 06:15 am:   Edit PostDelete PostView Post/Check IP

Patrick,

The key word is "had". When this whole saga started it was because the car suddenly started, in the words of my partner, "running as rough as a 10-dollar whore," one morning. (Which I mentioned in the previous thread.) At that point, depending on who knows what, I would either get the code P0300 (random misfire detected) or P0307 (misfire on cylinder 7) which eventually settled on the latter. I also would not say I had a misfire absent actual hard data for the same.

Since she was due for a spark plug replacement anyway, that was the first order of business. I also documented that while I could get 4 of the 8 plugs in (including the one on cylinder 7) I bailed on the other four and took it to my mechanic, who's got smaller hands than I do. He replaced the other 4 and then spent a week, off and on, doing various diagnostic tests and could not find any obvious issue.

It was after this that I decided to go on my electrical "cleaning" mission which, after completing it for the fuel injectors for the odd numbered cylinders, got rid of the rough running when cold at idle and more generally when driving entirely. All code throwing ceased.

Since then I have had the sensation of misfire under a very limited range of conditions which I have described in detail, twice, and am not getting codes thrown. My mechanic mentioned that this is not unusual if the misfire is transient (like one followed by everything being fine). The feel when it happens, though, is familiar enough for me to know that I have one.

I could find nothing unusual about the live data, but may not have been looking for the correct thing. If there is something specific I should be looking for please direct me to which value and what the normal versus abnormal condition would be.

I have just come in from "round 2" where I have made certain that the even numbered fuel injectors have received the same treatment as the odd ones had, as well as other electrical connections on that side. During today's work I discovered a small piece of vacuum hose, well hidden under that resonator and another electrical conduit, that had split at the barb connection in the foreground of this photograph:

Buick Split Vacuum Hose Location

As I had lots of 1/4" silicone hose that I had acquired for replacing vacuum lines on SRH33576 I cut a segment of that to replace what is missing in that photo above.

I will be off in a few minutes for her first run after all this, including having the Innova 3130 OBD and live data reader connected. I'll have to see how it goes now.

Brian
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David Gore
Moderator
Username: david_gore

Post Number: 2689
Registered: 4-2003
Posted on Wednesday, 11 October, 2017 - 07:02 am:   Edit PostDelete PostView Post/Check IP

Brian,

If all else fails, I suggest you take the vehicle for a continuous long highway drive [200/300 miles] at high speed to clean out any crud deposits in the cylinders/intake manifold. I have no faith in fuel additives claiming to remove internal deposits.

This is especially relevant to problems such as you are experiencing with cars that spend most, if not all, of their time doing low-speed town driving.

The old "Italian Tune-up" has a lot going for it.......
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2445
Registered: 6-2009
Posted on Wednesday, 11 October, 2017 - 08:09 am:   Edit PostDelete PostView Post/Check IP

David,

I am in a semi-Italian Tune-Up mode right now.

Even under normal circumstances I often drive at least 30 minutes one way at highway speed to get where I'm going.

No love this afternoon. I can still induce the issue under the same conditions I could before. At least I am not worried that I will end up stranded anymore. When this first started I wondered if the engine was going to shut down but I now know that's not what's going on. I could also, at the outset of "this phase" trigger the behavior in such a way that it would recur more times in a row in rapid succession than I can now. I only get one quick jerk at speed if and when it occurs.

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2447
Registered: 6-2009
Posted on Wednesday, 11 October, 2017 - 09:32 am:   Edit PostDelete PostView Post/Check IP

The "water spray test" gives not one iota of difference or useful data. No sparks, no stumbling, and this was soaking the plug wires repeatedly while the car was running and hitting the four that are clearly visible at the distributor on the front of the engine (and hoping I hit same on the opposing side that are hidden).

Didn't stumble at all with wet wires when I gunned the engine several times, either.

All while parked, of course, since one can't do this sort of observation on a moving car!!

Brian
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ross kowalski
Grand Master
Username: cdfpw

Post Number: 592
Registered: 11-2015
Posted on Wednesday, 11 October, 2017 - 01:27 pm:   Edit PostDelete PostView Post/Check IP

Brian,

Soaking the plug wires does give you one piece of useful data... don't buy plug wires.

On the other hand, what's wrong with 7?

The ODB is probably calculating the 0307 based on crank position sensor cylinder contribution so 7 isn't doing it's part. Weak or plugged Injector?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2449
Registered: 6-2009
Posted on Wednesday, 11 October, 2017 - 01:43 pm:   Edit PostDelete PostView Post/Check IP

Ross,

I am guessing I'm still dealing with number 7 but, as I have said repeatedly, the car is now no longer throwing a code of any sort.

When it was it was running so rough you knew something was off, very off. Now it's perfectly smooth except for the occasional tiny hiccup under the conditions I have outlined before and only above 60 MPH.

I'm going to try several tanks of gas with injector cleaner to see if it improves, because it has already done so since the first dose but I'm not through the first tank yet. I also need to follow Mr. Gore's advice and get out for a long drive with a lot of it at speed. Since the autumn leaves are now just prior to peak I'll have reason by this weekend.

Even if I were to switch injectors at this point it probably wouldn't tell me anything and all I could do is replace the injector on 7, which still might not do anything.

I hate these sorts of problems!

Brian
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ross kowalski
Grand Master
Username: cdfpw

Post Number: 594
Registered: 11-2015
Posted on Wednesday, 11 October, 2017 - 01:54 pm:   Edit PostDelete PostView Post/Check IP

Brian,

The Maranello tune up sounds lots more fun than a injector change. I'd try that first as well!
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1564
Registered: 9-2004
Posted on Thursday, 12 October, 2017 - 11:24 pm:   Edit PostDelete PostView Post/Check IP

Brian check all the plug firing k voltage in the live data look for abnormal variation.
If ok then check the cpc.
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Martin Taylor
Frequent User
Username: martin_taylor

Post Number: 96
Registered: 7-2013
Posted on Friday, 13 October, 2017 - 06:55 am:   Edit PostDelete PostView Post/Check IP

Brian, if it goes smoothly at part throttle acceleration but not when you push it to the floor at high revs I would suspect your fuel filter is partially blocked.
Low fuel pressure under load conditions will cause this.
Check by replacement or with a gauge, this is assuming your pump is ok.
I have experienced similar problems on a carbureted car that would only miss going up hills at high speed, after the entire ignition system was replaced it was found to be a fuel supply issue.
Worth a thought at least
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2454
Registered: 6-2009
Posted on Friday, 13 October, 2017 - 10:32 am:   Edit PostDelete PostView Post/Check IP

Martin,

Thanks for the thoughts, as they are genuinely appreciated, but what you're describing is the opposite of my issue. It absolutely never misbehaves when floored. In fact, if I am having the issue it is always at part throttle and the issue will resolve if I ease off OR push harder. It seems to be an "within a precise window" issue. What, exactly, that precise window entails is what I've been trying to flesh out. It has virtually always involved going up a grade when it occurs, though.

Also, at least so far, the Maranello tune up after the second tank of gasoline with a second bottle of fuel injector cleaner added appears to be causing positive change. I am not 100% back to normal but I am having a much more difficult time inducing the behavior and it's not nearly as consistent under the conditions where it normally occurred as it had been.

When all this was at the early stages I thought for certain that the 0-to-60 with WOT would have caused the car to misbehave, but it didn't, and I tried forcing it more than once and on level ground and going up grades.

Another long trip, in this case over the mountains, is on tap for tomorrow. I hope that yesterday and today have not been flukes (and with my luck they will have been). Nonetheless, I do not feel that there is any real risk of getting stranded.

Brian
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David Gore
Moderator
Username: david_gore

Post Number: 2694
Registered: 4-2003
Posted on Friday, 13 October, 2017 - 12:27 pm:   Edit PostDelete PostView Post/Check IP

Good luck with the extended trip - just don't get carried away and end up being victimised by the highway police.....................

It seems to me your problem has been in one or more fuel injectors; most likely a deposit that disrupts the fuel spray or acting as a glow plug in the combustion chamber to prematurely ignite the fuel mixture.
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Maxwell Heazlewood
Experienced User
Username: tasbent

Post Number: 48
Registered: 9-2017
Posted on Friday, 13 October, 2017 - 12:27 pm:   Edit PostDelete PostView Post/Check IP

Hello Brian....it is the Buick we're talking about isn't it?
I have been following this thread and noted what you describe.
Does the Buick have a throttle position sensor attached to the throttle body?
Your symptoms sound exactly like those exhibited by a worn sensor....how many miles on the beast?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2455
Registered: 6-2009
Posted on Friday, 13 October, 2017 - 01:17 pm:   Edit PostDelete PostView Post/Check IP

David,

Well, I am not trying to drive as though I'm in Wyoming during daylight hours (no speed limit - or at least that once was the case). I'm just going on long drives where I am running at normal highway speeds for as long as possible.

Tomorrow, speeds will likely be lower (as crossing the mountains on the roads I intend to use dictate that) but the engine will get a significant workout in the process.

I had actually not thought of the possibility of premature ignition but it makes every bit as much sense as a miss in causing a noticeable and very brief oddity in how power is being delivered that would disrupt smooth operation.

Maxwell,

Yes, the car under discussion is my 1996 Buick Roadmaster Estate Wagon. This is the only photo I can find of another that was not a faux woody:

1996 Roadmaster Estate Wagon

except mine is "Jadestone Blue Metallic" and showing a bit more age given that she's got a bit over 200K miles on her.

I have no idea where the throttle position sensor is located on this car. Research would be required on that question.

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 51
Registered: 9-2017
Posted on Friday, 13 October, 2017 - 02:18 pm:   Edit PostDelete PostView Post/Check IP

Brian...good looking vehicle ;o)
The Throttle Position Sensor will be attached to the side of the throttle body, usually on opposite to
throttle cable connection with a connector containing two wires....being a '96, will have fairly simple electronics ;o)....you can back probe with a multi-meter with ignition on but no start and watching the readings as you slowly rotate the throttle, you should get a smoothly increasing voltage reading....this is sometimes better to use an older analogue gauge to watch the smooth progression of the needle across the gauge.
If their is any wear or problem in the TPS it will show as a stagger....and this usually occurs just of closed throttle where most of the wear occurs ;o) They are as cheap as chips to replace and simple.;o)
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2456
Registered: 6-2009
Posted on Friday, 13 October, 2017 - 03:04 pm:   Edit PostDelete PostView Post/Check IP

Max,

I will commit sacrilege, but the "waftability" of that car far, far outstrips that of any SY era Rolls-Royce I've ever been in. That's one of the reasons I have kept this car and held on tight. She's been from Virginia to Texas and back several times because she's just so comfortable to travel in.

That, and I doubt you'll find much, even in contemporary large SUVs, that's more cavernous and convenient for hauling large items in an enclosed space. When going to see four grandchildren, all under age 10, on certain "gifting occasions" this is a "must have" feature!

Brian, off to bed since it's now 1:03 AM
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 53
Registered: 9-2017
Posted on Friday, 13 October, 2017 - 05:24 pm:   Edit PostDelete PostView Post/Check IP

Brian....I will vouch for that. I cannot understand the obsession with SUV's when a good station wagon will carry more anyway.
My Jaguar X308 has a far superior ride to any RR/Bentley that predates an Arnage.....which still lags behind the Jaguar X350 for ride suppleness.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2457
Registered: 6-2009
Posted on Saturday, 14 October, 2017 - 10:16 am:   Edit PostDelete PostView Post/Check IP

Max,

Your X308 is very similar to my 1999 XJ8L (also, of course, an X308) that I drove between 2006 and the end of 2013, at which point I sold it to a friend [who, by the way, remains a friend]. I adored that car and hated to part with it.

After today's run from Staunton to Hot Springs, VA, then back home over the mountain by another route through Deerfield, VA, I am giving your theory about the throttle position sensor (TPS) the top slot in the "try next" list. The misbehavior is exquisitely sensitive to throttle position coupled with a specific narrow range of speed and engine load. Even the slightest nudge above or drop below the very narrow "bucking zone" makes the car instantly enter smooth as silk mode.

I've ordered the TPS along with several replacement NGK spark plugs for the ongoing work on LRK37110, which I hope to continue with this weekend. I already have 8 NGK BPR4EY plugs in hand to put in SRH33576 when I get to it, so these are replacements for what I'll have to steal from that stock.

I will report back regarding what, if anything, was achieved after the new TPS is in on the land barge!

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 60
Registered: 9-2017
Posted on Saturday, 14 October, 2017 - 12:23 pm:   Edit PostDelete PostView Post/Check IP

Thanks Brian....I would place a fair bet that the TPS is the source of your niggling problem.....mind
you, I have been known to be wrong on the odd ocasion I'm assuming your fuel pressure is correct and you have a new fuel filter fitted?
I would be doing that before you start fiddling with plugs....a process of elimination.
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 76
Registered: 9-2017
Posted on Wednesday, 18 October, 2017 - 11:40 pm:   Edit PostDelete PostView Post/Check IP

Brian....how did you go with the diagnosis any
progress?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2460
Registered: 6-2009
Posted on Thursday, 19 October, 2017 - 10:01 am:   Edit PostDelete PostView Post/Check IP

Max,

Still waiting on the replacement TPS to show up on my doorstep. Will definitely be reporting after installation so that people have the outcome no matter what that outcome may be.

I'm big on supplying data points as well as asking for them!

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 79
Registered: 9-2017
Posted on Thursday, 19 October, 2017 - 12:50 pm:   Edit PostDelete PostView Post/Check IP

We'll be waiting with baited breath then Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2461
Registered: 6-2009
Posted on Saturday, 21 October, 2017 - 08:09 am:   Edit PostDelete PostView Post/Check IP

Latest Installment:

After the replacement of the TPS the issue is not 100% cured, but I do have definite changes.

It is much harder to induce a stumble/stutter and it is not possible to induce it with the precision/consistency that I could before. In addition, when they occur they are definitely more subtle than before.

Prior to today when they occurred the best way I can describe it was as though the engine stopped running for a few hundredths of a second. You could feel the instantaneous complete lack of power (or, probably more accurately, the jerk when it ended). Now you can definitely tell that the same class of thing is happening, but it must be quicker since the after jerk is a lot less intense.

I'm still going to keep driving to see if it eventually disappears entirely. Every step has gotten me closer and closer to 100% cure. But at this point I'm not certain which of the things I have done so far has been the biggest contributory factor.

For all I know today's differences could be the result of a fuel injector getting cleaner during the recent diagnostic test drives.

I'll keep everyone updated as to changes observed, whether for the better or worse, over the coming days and weeks.

I also need to do some research on what the live data logging capabilities of Torque Pro are. I have had no success in getting my Innova 3130 to connect to my computer and from what I've read it doesn't keep many frames of data. I can't be watching the device (or at least not at all closely) when I am driving. Having logged data would be very helpful and I have plenty of room on the microSD card on my smartphone to store it if that's a feature of Torque Pro.

Brian
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1581
Registered: 9-2004
Posted on Saturday, 21 October, 2017 - 09:32 am:   Edit PostDelete PostView Post/Check IP

Just to clear things up!
First you have a jerk fault, second you have a miss-fire, third you have it on number 7 cylinder.

It may not be so bad but it still there IMO the specific problem must be found they very rarely go away for long and come back to haunt you big time.
Can you confirm what type of plug leads are on the vehicle?
Also the plug firing KV.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2462
Registered: 6-2009
Posted on Saturday, 21 October, 2017 - 10:40 am:   Edit PostDelete PostView Post/Check IP

Patrick,

I really appreciate that you seem to want to help, but I am not going to be responsible for recapping everything for you that has already been covered in detail, with the correct chronology.

Please read the thread to which I gave a direct click through link in post 1 of this thread, then re-read this thread, if you want the correct chronology of issues and interventions. I'm not going through them again as I was quite thorough the first time around.

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 83
Registered: 9-2017
Posted on Saturday, 21 October, 2017 - 02:41 pm:   Edit PostDelete PostView Post/Check IP

Hello Brian....interesting to see there is some marginal improvement.
Differentiating this 'jerk' would help.
If it it is a strong stabbing kind of jerk, that is usually related to ignition sources.
A lighter fluffy sort of jerk is usually related to fuel problems.

Does this model have a MAF meter in the intake system?
Does this model have a BMAP (Barometric Mean Air Pressure)sensor in the intake system?

Have you ever had a closed loop fuel injection cleansing treatment performed on this engine....given the mileage it has covered?
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Jonas TRACHSEL
Prolific User
Username: jonas_trachsel

Post Number: 145
Registered: 2-2005
Posted on Saturday, 21 October, 2017 - 04:28 pm:   Edit PostDelete PostView Post/Check IP

Brian
Maybe what follows is humbug, but never-the-less here I go:
We used to pull suspicious injectors from diesel engines and tested them on a simple test bed. There you could see the spray pattern and any worn/defective injector was instantly visible. Have you ever pulled No 7 injector and placed on a test bed? Maybe you will have to test also a good injector to compare the spray pattern.
Jonas
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1583
Registered: 9-2004
Posted on Sunday, 22 October, 2017 - 12:31 am:   Edit PostDelete PostView Post/Check IP

Brian you say "but I am not going to be responsible for recapping everything for you that has already been covered in detail, with the correct chronology".
Really I have not seen you mention anything on the ABITS clever IMO but problematic it seems in many ways.

So once the resister leads are tested OK etc.
IMO this link on whole ABITS may well help!

https://www.youtube.com/watch?v=lFCjaz6zHfc
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Randy Roberson
Grand Master
Username: wascator

Post Number: 790
Registered: 5-2009
Posted on Thursday, 02 November, 2017 - 03:39 am:   Edit PostDelete PostView Post/Check IP

I recall that, in the early days of port fuel injection, carbon would build on the intake valve stem where the fuel continually impacted it. Eventually the engine would have a stumble or miss. BMW actually blasted valve stems with walnut shell with the head on the engine and recommended Chevron Techron fuel additive as a preventative, on a 318i I once owned.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2482
Registered: 6-2009
Posted on Thursday, 02 November, 2017 - 06:30 am:   Edit PostDelete PostView Post/Check IP

Randy,

Thanks. After the car has been allowed to sit for several days between drives I am right back to square one with the really rough idle, flashing "Service Engine Soon" light when driving at low speeds, and a P0307 code being thrown.

It gives me some comfort that the same issue keeps exhibiting itself when the car is throwing a code.

Now it's figuring out exactly why, again. I think I'm down to a fuel injector issue or a distributor issue. At over 200K miles it seems that one is not all that much more likely than another.

Brian
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Randy Roberson
Grand Master
Username: wascator

Post Number: 792
Registered: 5-2009
Posted on Thursday, 02 November, 2017 - 09:45 am:   Edit PostDelete PostView Post/Check IP

Can you swap the injector around, to see if the problem moves with it?
Also: is there anything in the intake manifold system that can leak air?
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Randy Roberson
Grand Master
Username: wascator

Post Number: 793
Registered: 5-2009
Posted on Thursday, 02 November, 2017 - 09:53 am:   Edit PostDelete PostView Post/Check IP

Torque converter clutch issue??
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2483
Registered: 6-2009
Posted on Thursday, 02 November, 2017 - 10:06 am:   Edit PostDelete PostView Post/Check IP

Randy,

I haven't seen anything obvious in the intake manifold that would leak, but I haven't been looking closely, either.

I haven't been willing to dive in to moving a fuel injector until this stage, and am considering doing that as the next diagnostic step. I need to do research on what's involved for the setup on this engine.

I'm becoming less inclined to believe that the transmission is at play, but will not rule it out, that's for sure.

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 84
Registered: 9-2017
Posted on Thursday, 02 November, 2017 - 10:22 am:   Edit PostDelete PostView Post/Check IP

Brian....I think it's high time you bit the bullet
and removed all the injectors from the old dunger for a sonic cleaning session
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1594
Registered: 9-2004
Posted on Friday, 03 November, 2017 - 06:29 am:   Edit PostDelete PostView Post/Check IP

This has all the hallmarks of an electrical fault on supply to number 7 with ABITS system.
New plugs fault almost cured, new plugs take less firing voltage: less misfire!

Cold and hot engine IMO injector failing is likely to be constant through all speed power ranges whatever the cause.

If the cylinder firing variation is more than 2% it will in most cases throw up a code.
More than 10% it will in most cases put the check light on, flashing if fitted can mean the cats are in DANGER unburnt fuel .

You know its time to do a tear down with the water pump.
Go for it.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2491
Registered: 6-2009
Posted on Sunday, 05 November, 2017 - 04:09 am:   Edit PostDelete PostView Post/Check IP

Patrick,

Not quite yet. I'm with you that it's not fuel injector related at this point.

I have also confirmed a few minutes ago that I have a weak spark when I have one, as its presence is inconsistent, on cylinder 7 now when the car is at rest, which must be more serious than before as the behavior seen way back when all this started with the old plugs was consistent at idle but sometimes went away as the car warmed up. The behavior initially changed with the new plugs such that idle and speeds up to highway speeds were dead smooth and highway speeds were smooth except for that stutter.

My next step is going to be substituting the plug wire to number 7 to see if that changes anything. I'll want new plug wires if I end up determining it's the distributor module anyway, but better to see if it could be the wire first. It strikes me as odd, but not impossible, that the distributor module, if failing, would do so on one output only.

If it's not the plug wire I'll probably have someone else "bite the bullet" and do the installation of the distributor module for me. It's more of an undertaking than I want to make in my driveway.

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 94
Registered: 9-2017
Posted on Monday, 13 November, 2017 - 01:58 pm:   Edit PostDelete PostView Post/Check IP

OK Brian....have you worked out your EFI/ignition problem/s yet?
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2504
Registered: 6-2009
Posted on Monday, 13 November, 2017 - 11:28 pm:   Edit PostDelete PostView Post/Check IP

Max,

No, "Mom issues" [I have a mother with dementia] came up as did several other things.

I have acquired a replacement spark plug wire set, and had every intention of installing them this past weekend, but decided to punt on that when I determined that dealing with the "space issues" was more than I wanted to deal with right now. The appointment to have my mechanic install these is currently set for next Monday.

If this isn't the cure I can't see how it could be anything other than the distributor at this point.

Brian
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Maxwell Heazlewood
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Username: tasbent

Post Number: 96
Registered: 9-2017
Posted on Tuesday, 14 November, 2017 - 10:19 pm:   Edit PostDelete PostView Post/Check IP

Hello Brian....sorry to hear about your Mum' dementia....a very good friend of mine recently passed away with this ailment and she was such a beautiful lady.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2511
Registered: 6-2009
Posted on Tuesday, 21 November, 2017 - 07:50 am:   Edit PostDelete PostView Post/Check IP

Latest brief update: Went into the shop today for plug wire replacement. When I called just before closing my mechanic said: I've spent an hour and a half, so far, trying to get these things in, and I'm still not done!

No real surprise there, at all. After I saw how these things were routed and held into place I knew that I did not want to be the one doing this job. Even if it takes him 3 hours the money will be well spent to save my sanity and my fingers!

Brian
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Maxwell Heazlewood
Frequent User
Username: tasbent

Post Number: 100
Registered: 9-2017
Posted on Tuesday, 21 November, 2017 - 11:00 am:   Edit PostDelete PostView Post/Check IP

Well Brian...you're getting a little closer to solving the problem And at least someone else is having the grief of fitting the leads.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2512
Registered: 6-2009
Posted on Thursday, 23 November, 2017 - 01:40 am:   Edit PostDelete PostView Post/Check IP

Max,

Definitely the best $70 I ever spent (about $90 if you count the parts)!

Until I drive the car more I am not willing to declare her cured, but all early indications are that she is, indeed, cured. I took an extended drive home from the shop last night and she purred from the first turn of the key until I parked her. That has not been the case even once since this whole adventure started.

I will be avoiding any of the major roadways today, however. The day before Thanksgiving (US) is the absolute worst time to be on the road! I do not miss traveling for this holiday one bit!

Brian
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Randy Roberson
Grand Master
Username: wascator

Post Number: 794
Registered: 5-2009
Posted on Thursday, 23 November, 2017 - 05:56 am:   Edit PostDelete PostView Post/Check IP

Great!
I recall replacing the secondary wires on the Wraith II: seemed tougher to get the old ones off until I got my nerve up and cut the old ones out. Going in with the new ones wasn’t asbad as I expected.
I hope this solves your issue.
Have a Happy Thanksgiving!
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2516
Registered: 6-2009
Posted on Thursday, 23 November, 2017 - 07:15 am:   Edit PostDelete PostView Post/Check IP

Randy,

After some additional driving, I am convinced that the issue with the misfire is cured.

It appears that the cure has induced a different (and small) issue. The car still runs as smoothly as it should but within a minute or two, even if I clear it, a P0113 code is being thrown: Intake Air Temperature (IAT) sensor circuit high input problem.

From what I'm reading one of the possible causes of this is the routing of a plug wire too near to the sensor itself or the sensor wires.

When I look at the data in Torque it seems to think that it's -40 degrees F outside, which it definitively is not.

Since I didn't install these things I'm taking her back to have that looked at. Clearly she was just backed out of the garage to be parked again after the wires were installed. It doesn't take very long if driving the thing for this code to occur, and is occurring consistently. I find it a bit too coincidental to believe it's unrelated to the latest repair.

Brian, and a Happy Thanksgiving to your and yours as well
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Maxwell Heazlewood
Prolific User
Username: tasbent

Post Number: 104
Registered: 9-2017
Posted on Thursday, 23 November, 2017 - 11:51 am:   Edit PostDelete PostView Post/Check IP

Hello Brian...good to hear you have the problem resolved.....now, let's hope your 'new' problem
is as easy to solve
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2517
Registered: 6-2009
Posted on Thursday, 23 November, 2017 - 01:49 pm:   Edit PostDelete PostView Post/Check IP

Max,

Based on what I found researching that code I suspect that either the sensor is shorted or the new spark plug wires are routed too close to it.

This should be a far less extensive problem to narrow down than the last one!

Brian
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Maxwell Heazlewood
Prolific User
Username: tasbent

Post Number: 109
Registered: 9-2017
Posted on Thursday, 23 November, 2017 - 04:04 pm:   Edit PostDelete PostView Post/Check IP

Brian....given the age and mileage of the beast, I would suspect the sensor is past it's use by date
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1638
Registered: 9-2004
Posted on Thursday, 23 November, 2017 - 07:07 pm:   Edit PostDelete PostView Post/Check IP

Considering all the new plug leads just fitted when only one was needed, if a KV output or Ohms resister test was carried out in the first instant his would have shown up no 7 lead failing.
In this case it the most likely that there would not be any discharge from the new plug lead to the ITA harness.
IMO it sounds like a default reading for when the circuit is open, the cable might be broken inside the insulation but in this case the ITA connector may not be making the necessary connection after being disturbed.
Time to do a few simple tests.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2518
Registered: 6-2009
Posted on Friday, 24 November, 2017 - 05:45 am:   Edit PostDelete PostView Post/Check IP

Solution found: Reconnect sensor.

The mechanic had accidentally failed to do this and I had not found the correct location yesterday.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1851
Registered: 5-2012
Posted on Friday, 24 November, 2017 - 06:45 am:   Edit PostDelete PostView Post/Check IP

Great news Brian - so nice when the solution is to correct a simple oversight.

Patrick - I always find it best to replace all the leads if one fails, assuming they are the same age. They are low cost and it's good preventative practice.
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Maxwell Heazlewood
Prolific User
Username: tasbent

Post Number: 110
Registered: 9-2017
Posted on Friday, 24 November, 2017 - 06:51 am:   Edit PostDelete PostView Post/Check IP

Good to hear it all worked out in the end Brian.
I agree with Geoff....for the price it's always better to replace in a set....if one goes, others are sure to follow which just creates and endless set of problems.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2519
Registered: 6-2009
Posted on Friday, 24 November, 2017 - 09:51 am:   Edit PostDelete PostView Post/Check IP

Max and Geoff,

It was indeed a huge relief when I opened the hood today, looked in, and had the offending dangling connector nearly jump out and bite me. The reference materials I have cover (with photos) where this thing is located in 1993 and earlier variants, but they didn't add a photo for the 1994 and later models. Thus I was digging around a bit too far upstream of the actual location on the air intake and was in a hurry when I was doing so.

Today's drive was completely smooth and without a single code thrown.

Even if I had the option to replace a single spark plug wire I probably wouldn't have exercised that, anyway. I figure that if one of these things is failing in some way, and all the others are of the same age and operating under similar conditions, another will likely go in short order. I find that things like wiring that are operating under harsh conditions tend to fail in rapid succession. Oddly, this has been the exact opposite of my experience with electronic things like ignition coils in coil on plug setups. There were people who swore, up and down, that when one ignition coil on my Jag failed that I had to replace all eight of them. After reading a lot about other's experiences it seemed to me that the failure of an individual unit was rather random. While I bought several spares, I only replaced three of the eight during my entire period of ownership and those three were not in rapid succession. The things would just up and die with no rhyme or reason and a roadside change took all of 15 minutes the one time I had to do one. I think the three failures were over a period of approximately 5 years. The remaining 5 were never changed during the period a friend owned the car for several years, before its untimely demise due to an accident.

Brian
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1642
Registered: 9-2004
Posted on Friday, 24 November, 2017 - 10:01 am:   Edit PostDelete PostView Post/Check IP

Common mistake for some when checking procedure is not followed, replace some suspecting items, and when the fault is still present replace more.
Only when the fault is found ie plug or in this case plug lead then replace all.
IMO this is not the end of the story long term due to the lost spark effect on the ABITS system.
Go figure...............
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Randy Roberson
Grand Master
Username: wascator

Post Number: 795
Registered: 5-2009
Posted on Friday, 24 November, 2017 - 09:56 pm:   Edit PostDelete PostView Post/Check IP

In my case replacing the set seemed much easier than replacing one wire. The wires were old and the cost was not high.
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ross kowalski
Grand Master
Username: cdfpw

Post Number: 637
Registered: 11-2015
Posted on Friday, 24 November, 2017 - 10:28 pm:   Edit PostDelete PostView Post/Check IP

Brian,

Good that's done. I'll always take a good ol' "won't crank" or "dead cylinder" over any sort of "does something kind often under the same conditions"

Now, back to the "real" cars.

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