So reliable for so long then..... Log Out | Topics | Search
Moderators | Register | Edit Profile

Australian RR Forums » Silver Shadow Series » So reliable for so long then..... « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 147
Registered: 11-2016
Posted on Sunday, 20 August, 2017 - 02:59 am:   Edit PostDelete PostView Post/Check IP

Hi Guys

SRH 17968 Shadow 1 has been so reliable for so long, travelling Spain and Morocco without a serious hitch.

I then parked her up for a while (3 weeks).

When I went to start her, she fired up first time as usual, but after about a minute of running, she cut out unexpectedly.

She started again without a problem, but this happened twice more over the next 5 minutes. I let her warm up, and she ran for another 10 minutes, and then I switched her off.


I took her out today, and again this happened three times in the space of 10 minutes.

The last time it happened she would start and then cut out nearly immediately. This happened 4 or 5 times consqutively, after which she started and ran fine back to the garage!

What I noticed:
1. When she cuts out, everything else keeps working, blowers, lights etc so it is not a loose battery terminal etc.
2. There is fuel in the float, so it is not fuel pumps etc. I suppose it could be something to do with the weakener can. I know blocking the inlet pipe on that can make the engine stop as if it were an electrical fault.
3. ODDLY! A few of the times that I tried to restart her, the starter motor would not engage. I tried moving from Park to Neutral in case it was the safety switch but that did not help.
Then I tried keeping the ignition switch against the spring as if I was trying to crank, and moved the gear lever into Park and it cranked and started. I had to do this a few times!!

So I thought it might be the gearbox safety switch, but that only prevents cranking when the lever is not in P or N, it does not cut out the ignition.

Has this happened to anybody? Does anyone have any ideas. The problem is that it is intermittent and there is probably a cable loose somewhere.

I will be examining the wiring diagram tonight to see if there is any joy.

Thanks
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 148
Registered: 11-2016
Posted on Sunday, 20 August, 2017 - 03:58 am:   Edit PostDelete PostView Post/Check IP

Sorry, I forgot to mention that I installed electronic ignition about a year ago which is another possible culprit. I am investigating how to test this out.
Top of pagePrevious messageNext messageBottom of page Link to this message

richard george yeaman
Grand Master
Username: richyrich

Post Number: 791
Registered: 4-2012
Posted on Sunday, 20 August, 2017 - 04:31 am:   Edit PostDelete PostView Post/Check IP

Patrick it may be worth checking the fuel quality, and also when you fitted your electronic ignition did you do away with the ballast resistor.

Richard.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1449
Registered: 9-2004
Posted on Sunday, 20 August, 2017 - 04:33 am:   Edit PostDelete PostView Post/Check IP

My first thought would be the electronic ignition module failing.
The starter selenoid may be another cause of the starter not working
Second would be bad connection on the coil terminals.
Third would be the ignition switch contacts failing.
Time for some testing.
Top of pagePrevious messageNext messageBottom of page Link to this message

Jim Walters
Prolific User
Username: jim_walters

Post Number: 118
Registered: 1-2014
Posted on Sunday, 20 August, 2017 - 04:53 am:   Edit PostDelete PostView Post/Check IP

Hook up a test light between the coil + and ground. It will flash regularly if the ignition module is trying to fire the coil. If it dies while it is still flashing then that tells you the module is OK and trying to fire the coil and you need to look elsewhere like coil itself, shorted rotor, etc. If the test light stops flashing and stays on without flashing THEN it dies you have an ignition module fault. If it quits flashing and goes off then the engine dies you have an ignition switch or fuse issue.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
Top of pagePrevious messageNext messageBottom of page Link to this message

Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 82
Registered: 5-2016
Posted on Sunday, 20 August, 2017 - 09:28 am:   Edit PostDelete PostView Post/Check IP

Another possibility is the oil pressure switch at the lower front of the engine, it's wired to cut off the ignition if the oil pressure is too low. Could be that the switch is faulty or the wiring to it is not making a good contact.
Top of pagePrevious messageNext messageBottom of page Link to this message

Brian Vogel
Grand Master
Username: guyslp

Post Number: 2383
Registered: 6-2009
Posted on Sunday, 20 August, 2017 - 11:44 am:   Edit PostDelete PostView Post/Check IP

Patrick,

I believe you may have two completely separate problems (or, perhaps three) that are coincidentally occurring nearly concurrently.

Larry's observation about the oil pressure cutoff switch is a good place to start with regard to the engine just stopping, as it's easy to pull the connection off of it and that effectively makes the car believe it has adequate oil pressure (and it almost assuredly does when running). If this behavior stops this is a very easy item to replace.

The behavior you describe in reference to the starter was exactly what I had occurring for a period of several years, getting more frequent over time, until the car would not crank at all. It was the OEM Lucas starter giving up the ghost, but slowly. If you wish to keep it they can be thoroughly checked over and overhauled by any really good automotive electrician who does electric motor work. Many of us do as I did and replace it with a gear reduction starter. Just something to think about and keep your eye on.

Brian
Top of pagePrevious messageNext messageBottom of page Link to this message

Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1751
Registered: 5-2012
Posted on Sunday, 20 August, 2017 - 01:03 pm:   Edit PostDelete PostView Post/Check IP

I'm following this one closely as I am interested to see if the cause is the electronic ignition. I had one fail and reverted to points and I note that John Beech has recently reported the same with his ex-pertronix system.

I agree with Brian that there appear to be two unrelated faults here. The starter motor problem is a common one on these cars. It's worth checking the connections at the starter motor first. They can get oily and current can leak. It's also worth checking the starter motor relay as well, just in case that is causing the problem.

I note Patrick's car is a "series 1" so will not have the low oil pressure cutoff system fitted.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 149
Registered: 11-2016
Posted on Sunday, 20 August, 2017 - 04:08 pm:   Edit PostDelete PostView Post/Check IP

Thank you all- I will keep you posted!. Geoff you are right about the low pressure cut out, mine does not have it. I had a loose cable a while back and all it did was illuminate the low oil pressure light.
Top of pagePrevious messageNext messageBottom of page Link to this message

h_kelly
Prolific User
Username: h_kelly

Post Number: 223
Registered: 3-2012
Posted on Sunday, 20 August, 2017 - 06:03 pm:   Edit PostDelete PostView Post/Check IP

Patrick, did you by any chance jump start the car?. Jump starting certain electronic ignitions can cause damage to same.
Separately with ignition on move gear shift through gears and listen for actuator to move, this will rule out same.
Finally.. Question, if the main lead to starter is loose could it cause current symptoms (I'm not sure but I'm sure someone will advise on same)?.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 150
Registered: 11-2016
Posted on Sunday, 20 August, 2017 - 09:44 pm:   Edit PostDelete PostView Post/Check IP

Hi H

You are absolutely right about the jump starting. There is a definite procedure with electronic ignition (you cannot have donor car running with the receiving car's ignition on).

I jump started her a while back (so easy to leave the lights on in the day time!) and followed procedure and it worked a treat.

Interestingly, the actuator moves with the gear lever as it should, but also there is always a clunk from the actuator when I switch the ignition on with the lever in gear. More of a clunk if the lever is in P,R,N or D and less of a clunk if it is in I or L - is this normal?

Main lead to the starter and solenoid etc is my first port of call today - I will let you know.

Thanks
Top of pagePrevious messageNext messageBottom of page Link to this message

ross kowalski
Grand Master
Username: cdfpw

Post Number: 509
Registered: 11-2015
Posted on Monday, 21 August, 2017 - 01:54 am:   Edit PostDelete PostView Post/Check IP

Patrick,

First off, if you didn't have to get towed, then it's not officially an FTP. So that's a relief.

It's hard to believe the cutting out and starting issues are related, but then again, there's some pretty weird things out there. Good check on the float bowls BTW, that is a pretty definitive test saying it's electrical.

It seems like it's doing the cut out behavior pretty consistently which makes diagnosis easier.

A good next test is to figure out if it's the electronic ignition or the chassis harness BS (Supporting Systems) A good way of doing this would be to attach a jumper cable from a constant 12v source to the power input of the electronic ignition. (do this with the car off to avoid sparks) I would also jump the ground wire to the electronic ignition to a known good ground.

If the car keeps cutting out then it's the electronic ignition, get a replacement. If it stops, then it's in the chassis harness / wiring somewhere.

If you don't have a set of jumper wires then that will be a problem. Jumper wires and test lights take a lot of the guess work out of trouble shooting.
Top of pagePrevious messageNext messageBottom of page Link to this message

Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1752
Registered: 5-2012
Posted on Monday, 21 August, 2017 - 02:05 am:   Edit PostDelete PostView Post/Check IP

Hi Patrick

Re: I tried keeping the ignition switch against the spring as if I was trying to crank, and moved the gear lever into Park and it cranked and started. I had to do this a few times!!

I'm wondering if this indicates a worn contact in the ignition switchbox or starter relay. Closing the switch/relay contacts first and then applying the load, which is what you are doing, seems to me a good way of overcoming a worn contact.

All will come out in the wash as you investigate it. Please let us know the outcome.

Geoff
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 151
Registered: 11-2016
Posted on Monday, 21 August, 2017 - 02:25 am:   Edit PostDelete PostView Post/Check IP

Hi Guys
I have a friend that has a Mark 5 RR and is a keen enthusiast, going to all the courses etc and a member of most clubs etc.
I told him a while back that the Australian RROC is one of the best and most helpful sites that I know. The other day, he confirmed my findings.
Thank you all for your continuous unselfish help, without which a lot of our cars would be roadside junk.
If only certain aspects of our world could take a leaf out of this book, we would have a better world to live in.

And now to my problem:
I spent most of the day checking everything that has been mentioned - started motor, connections electronic ignition, ignition switch (as far as I could without dismantling everything.
Once I had checked and found that everything seemed as it should be, I then started her up and carefully drove around trying to get the problem to repeat itself so that I could check further.
As I was driving, suddenly my aircon gave up, so I stopped and checked that I had gas in the sightglass, and then if I was getting 12v to the clutch actuator, which it wasn't. For no reason, it came back on again, so I got back in the car and carried on trying to get the other fault to rpeat itself.
Then the aircon gave up again, and this time I noticed the fuel gauge also stopped working - and then I remembererd!!
When the car stalled yesterday for the Nth time, as a shot in the dark, I swapped the ignition fuse for then one above it (a/con fuse!).
The problem has been a dry solder on the ignition fuse which was manifesting itself erratically, probably when the fuse heated up a bit.
I cannot get the fuse to fail on then test bed - only under load.
So thank you all again for your help and ideas. Luckily this time it was a simple solution.

On another note, my clock and undrbonnet light failed at the same time about a week ago. Before I start the laborious job of searching for the loose cable, does anyone know if there is anything in common to the two? Everything else on that fuse works fine.
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Grand Master
Username: omar

Post Number: 1282
Registered: 4-2009
Posted on Monday, 21 August, 2017 - 04:18 am:   Edit PostDelete PostView Post/Check IP

You have just jogged my memory to buy a few of these fuses to keep as spares.
Who knows where can we buy these on the open market?
I mean the little fat fuses.
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 2636
Registered: 4-2003
Posted on Monday, 21 August, 2017 - 10:22 am:   Edit PostDelete PostView Post/Check IP

Omar,

An electronic enthusiast's supplier would be a good place to start - the fuses come in 2 types; slow-blow and fast-blow and I have forgotten which type is used for vehicles however the following link has a comprehensive summary which might help:

https://electronics.stackexchange.com/questions/25055/slow-blow-vs-fast-acting-fuse

*
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 152
Registered: 11-2016
Posted on Tuesday, 22 August, 2017 - 01:59 am:   Edit PostDelete PostView Post/Check IP

I am shocked at how lucky I was to find the fault. This could have turned into a neverending saga!
A fuse that fails occasionally and only under load- and that particular one- would have had me changing electronic ignition and all sorts. I am now changing all my fuses since they have been there since 1974! Searching for them
Suggest we all do?
Top of pagePrevious messageNext messageBottom of page Link to this message

gordon le feuvre
Prolific User
Username: triumph

Post Number: 201
Registered: 7-2012
Posted on Tuesday, 22 August, 2017 - 06:30 pm:   Edit PostDelete PostView Post/Check IP

Had exactly same issue with my '73 fixed head Corniche. had issue that caused fuse to blow. Sorted very quickly, but replaced with original spare fuse. This blew, sent me all over place searching for non existent problem. Replace with new fuse, all ok, so replaced them all. No further issues.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 153
Registered: 11-2016
Posted on Tuesday, 22 August, 2017 - 06:34 pm:   Edit PostDelete PostView Post/Check IP

Hi Omar
Done a bit of research and it seems that Flying spares are the only people that I can find that have the 17mmx6.3mm 10A fuses at about 1 each.
The 32mmx6.3mm 30A fuses are reasonably common and easy to get on ebay etc
Top of pagePrevious messageNext messageBottom of page Link to this message

Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1839
Registered: 6-2006
Posted on Tuesday, 22 August, 2017 - 06:36 pm:   Edit PostDelete PostView Post/Check IP

The bad news is that they are prone to doing this. I always tell clients and the RAC etc to swap them around if they have a problem to see if the fault moves. No point in just checking with a test lamp as you have found.

The good news is that it is possible to resolder the ends so they have a good joint. So repairing or reconditioning the whole lot in a winters evening is a nice indoors project.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 154
Registered: 11-2016
Posted on Tuesday, 22 August, 2017 - 11:29 pm:   Edit PostDelete PostView Post/Check IP

A question to the learned please:
I have an original bobbin with 22A fusewire wrapped round it.
I have just bought some fusewire at the electric shop which has 5A, 15A and 30A fusewire selection, but all three of these options are thicker in diameter than the original 22A wire.
Does the thickness necessarily have a bearing on the blow rating?
Top of pagePrevious messageNext messageBottom of page Link to this message

Geoff Wootton
Grand Master
Username: dounraey

Post Number: 1753
Registered: 5-2012
Posted on Wednesday, 23 August, 2017 - 01:39 am:   Edit PostDelete PostView Post/Check IP

Hi Patrick

All metals have different rates of electrical conductivity. Copper, for instance, is a much better conductor that Brass. So it depends on what metal/alloy your fuse wires are made of. I'm surprised however that the 5 Amp wire from the electric shop is thicker than the 22 Amp wire on the original bobbin.

If the electric wire is rated at 15A, then that is the rating and I would personally use, as it is closest to the specified 22A.

The Handbook specifies single strand 30 SWG tinned copper wire. (page 121 of the online copy)

wire

Geoff
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 155
Registered: 11-2016
Posted on Wednesday, 23 August, 2017 - 07:20 am:   Edit PostDelete PostView Post/Check IP

Hi Geoff

The wire on the spool may not be original - then again it may be!

I'll cut a length of each and take a resistance reading as a matter of interest.

Let you know.......
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Grand Master
Username: omar

Post Number: 1283
Registered: 4-2009
Posted on Wednesday, 23 August, 2017 - 12:44 pm:   Edit PostDelete PostView Post/Check IP

Dear David and Patrick
Many Thanks.
So it is flying spares or nobody....
I guess I will be buying from them soon.
Take care.
Omar
Top of pagePrevious messageNext messageBottom of page Link to this message

ross kowalski
Grand Master
Username: cdfpw

Post Number: 513
Registered: 11-2015
Posted on Thursday, 24 August, 2017 - 11:11 am:   Edit PostDelete PostView Post/Check IP

Patrick F,

Can you run 4 lengths of the 5A?
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Francis
Prolific User
Username: jackpot

Post Number: 158
Registered: 11-2016
Posted on Thursday, 24 August, 2017 - 08:59 pm:   Edit PostDelete PostView Post/Check IP

Hi Ross
I have been scratching my head trying to remember my a-level physics.
Does 4x 5 = 20A, or will electricity take the path of least resistance and blow at a lower rating??
Gentlemen, choose your weapons.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 445
Registered: 10-2008
Posted on Thursday, 24 August, 2017 - 10:48 pm:   Edit PostDelete PostView Post/Check IP

Patrick, I think the 4 strands would act as 4 resistors in parallel. If the resistances are identical , then in theory all would carry the same current and blow at the same time. Theory and practice however differ and although the fuse wire is relatively "slow blow", I suspect failure will be at under 20 amps.
See https://www.tlc-direct.co.uk/Products/TLFW20.html
Purely my guess !!!
Mark
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1453
Registered: 9-2004
Posted on Friday, 25 August, 2017 - 01:01 am:   Edit PostDelete PostView Post/Check IP

IMO wrong, 4x 5a strands will take more than 20a.
More heat loss, go figure.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 446
Registered: 10-2008
Posted on Friday, 25 August, 2017 - 03:36 am:   Edit PostDelete PostView Post/Check IP

Patrick, my reasoning is that the resistances in practice will not be equal and applying ohms law to each strand and calculating the heat produced in each strand would suggest a cascading effect ie a 20amp fuse becomes a 15 amp fuse becomes a 10 fuse etc.as melting temperature in each strand will happen at a different times. A simple bench test would prove or disprove this. The additional heat loss would however have a bearing on the outcome. Interesting teaser !
Personally, I would use 20 amp fuse wire, or consider converting to a 20 amp resettable cut out, which I did for several fuses in my old Spirit.
Mark
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 2639
Registered: 4-2003
Posted on Friday, 25 August, 2017 - 08:48 am:   Edit PostDelete PostView Post/Check IP

A probable solution with multiple strand replacements would be to twist the multiple wires together to make a single wire for the fuse; if one strand fails, the other adjacent strands will quickly fail as they can no longer carry the rated current.

This can be easily tested with a simple test rig using a battery, amp meter, rheostat and terminals/fuse holder connectors.
Top of pagePrevious messageNext messageBottom of page Link to this message

ross kowalski
Grand Master
Username: cdfpw

Post Number: 515
Registered: 11-2015
Posted on Saturday, 26 August, 2017 - 05:49 am:   Edit PostDelete PostView Post/Check IP

Patrick,

Pretty sure you can do the 4 wires trick. Most circuits have a lot of headroom. Lots of cars have 10 ga wire protected with 30A fusing for headlights. If you think about that, if a person had 60W low beams and 60W highbeams and they ran all the filiments at the same time that would only be 240W far less than the 420W that 30A fusing would protect at.

David,

Good call on the twisting the wires together idea.

Mark,

What would actually be going on with the 4 wires in use and in failure would be pretty interesting I bet.

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Please quote Chassis Numbers for all vehicles mentioned.
Password:
E-mail:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: