Jerking and stalling until 30mins int... Log Out | Topics | Search
Moderators | Register | Edit Profile

Australian RR Forums » Silver Shadow Series » Jerking and stalling until 30mins into driving « Previous Next »

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

tanluhan
Unregistered guest
Posted From: 58.96.231.94
Posted on Saturday, 06 January, 2018 - 02:18 am:   Edit PostDelete PostView Post/Check IP

Hi guys, my shadow has bee acting up recently. When i first got the car, it used to require 10mins or so of running at high rev to warm up, and thereafter, the vehicle will be smooth as silk.

However, now it takes longer and longer to warm up, sometimes even 30mins, and in the 30mins, the vehicle will run extremely rough, it will jerk and will stall if not even gas is given. Even if i floor the pedal, i will be jerky to move off, and might stall as well. After this warmup period, the vehicle will run great, no jerks and no stalls.

I have changed the sparks, spark cables, adjusted the timing to the best of my ability (any other position would cause the vehicle to run not as smoothly). The ignition coil is a new flamethrower coil as well. My suspect is on the carbs as there is not much left to change on the ignition side. Appreciate any advice, thanks!

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 2801
Registered: 4-2003
Posted on Saturday, 06 January, 2018 - 06:48 am:   Edit PostDelete PostView Post/Check IP

Please advise chassis number and country of delivery for original purchaser of your car so our members can provide more specific advice on possible causes and remedies.
Top of pagePrevious messageNext messageBottom of page Link to this message

Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 1659
Registered: 5-2015
Posted on Saturday, 06 January, 2018 - 07:20 am:   Edit PostDelete PostView Post/Check IP

Assuming SU carbs

Check choke operation.
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Grand Master
Username: omar

Post Number: 1388
Registered: 4-2009
Posted on Saturday, 06 January, 2018 - 03:01 pm:   Edit PostDelete PostView Post/Check IP

David is right. We need to have car details.
However, if i were to take a stab at it..... one of your carburettor pistons is getting caught. The pistons need to slide up and down in their chambers smoothly. If one of these stick, you could get what you are experiencing.
Top of pagePrevious messageNext messageBottom of page Link to this message

tanluhan
Unregistered guest
Posted From: 58.96.231.94
Posted on Sunday, 07 January, 2018 - 12:51 pm:   Edit PostDelete PostView Post/Check IP

Hi, to add , its a UK vehicle. By warming up, i do not mean the temperature on the gauge. The car warms up nicely, but takes an even longer time to start running smoothly. Im located in Singapore, hence the weather is always warm, which mean there should be no need for the termostat to kick in/out.

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

luhan tan
Unregistered guest
Posted From: 58.96.231.94
Posted on Sunday, 07 January, 2018 - 12:43 pm:   Edit PostDelete PostView Post/Check IP

Hi guys, thanks for the advise. Sorry my vehicle is a SRH32914. For the choke operation, do i have to take apart the carb?

When i start it, it revs highly, for some time, i can bring it down by stepping on the gas. But even at idling it will continue to run rough for up to 30mins of driving. The rough running and stalling is only during move off of the vehicle. Once it passes 10kph or so, it will be smooth. The high speeds(110kph) will be smooth as well

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

tanluhan
Unregistered guest
Posted From: 58.96.231.94
Posted on Sunday, 07 January, 2018 - 01:04 pm:   Edit PostDelete PostView Post/Check IP

i would also want to add that, if i drive the car everyday, this issue will not happen. The longer it sits in the garage, the more time it takes for the vehicle to 'recover' to its normal driving state.

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1989
Registered: 6-2006
Posted on Sunday, 07 January, 2018 - 04:13 pm:   Edit PostDelete PostView Post/Check IP

Hi, you can see if the choke is working ok by viewing the image on the right hand side of the carb intake.

It will be down when starting cold and should move upwards as the engine warms. Probably within a few minutes where you are.

It may be a weakened problem. Locate the small ish float chamber vent hoses ( the one in front of the left hand carb is easiest ) and disconnect it. Then take for a test drive.
Top of pagePrevious messageNext messageBottom of page Link to this message

Alan Dibley
Prolific User
Username: alsdibley

Post Number: 118
Registered: 10-2009
Posted on Sunday, 07 January, 2018 - 08:09 pm:   Edit PostDelete PostView Post/Check IP

Check the level of fluid in the gearbox. If it's low it can give similar symptoms.

Check with engine warm and idling.

How do I know?.......

Note that the choke has nothing to do with the carbs. It works by closing down the intake plenum before the carbs.

Regards from Alan D.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1712
Registered: 9-2004
Posted on Sunday, 07 January, 2018 - 08:58 pm:   Edit PostDelete PostView Post/Check IP

Worth checking the stove pipes for cracking/ holed.
If these have failed it can delay the warming up process on automatic choke system.



BTW not used with LPG.


Top of pagePrevious messageNext messageBottom of page Link to this message

Jeff Young
Grand Master
Username: jeyjey

Post Number: 364
Registered: 10-2010
Posted on Sunday, 07 January, 2018 - 09:12 pm:   Edit PostDelete PostView Post/Check IP

I would think this:

i would also want to add that, if i drive the car everyday, this issue will not happen. The longer it sits in the garage, the more time it takes for the vehicle to 'recover' to its normal driving state.

reinforces Omar's suggestion of a sticky carb piston.
Top of pagePrevious messageNext messageBottom of page Link to this message

tanluhan
Unregistered guest
Posted From: 58.96.231.94
Posted on Sunday, 07 January, 2018 - 08:58 pm:   Edit PostDelete PostView Post/Check IP

Spent the afternoon tinkering with the rolls. The choke is working, took it out and played with it by turning the center portion of the spring left and right.

plugged out the weakener, and plugged it with a bolt. no difference between plugged and unplugged.

toyed with the timing, already at the optimum mark.

opened up distributor cap, looks good. eletronic ignition looks new(lucas).

Even when engine is well and warm, it is unable to idle with 100% smoothness, with very slight misfire here and there, which can be easily seen from a sharp drop in the ampmeter everytime a misfire happens. I can conclude that the stall and jerking is the severe symptom of the unsmooth idling, exaggerated by the cold and newly started engine. Hence, to solve this issue, the cause of the unsmooth idling must be found. As of yet, i do not have any other leads, other than rebuilding the carbs or changing out the eletronic ignition. Everything else relating to the firing of the engine seems be in good working order.

@alan the gearbox oil is full. dont think it affects match as it is a idling problem

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1713
Registered: 9-2004
Posted on Sunday, 07 January, 2018 - 09:39 pm:   Edit PostDelete PostView Post/Check IP

"Even when engine is well and warm, it is unable to idle with 100% smoothness, with very slight misfire here and there."

Not the stove pipes in that case.

My Shadow 2 had this type of fault for a period before the Opus electronic distributor module packed up.
A posting on the system etc has been covered.
Top of pagePrevious messageNext messageBottom of page Link to this message

Jeff Young
Grand Master
Username: jeyjey

Post Number: 365
Registered: 10-2010
Posted on Sunday, 07 January, 2018 - 10:05 pm:   Edit PostDelete PostView Post/Check IP

It's worth checking to see if the carb pistons are all gunked up before moving on to other more involved things.

https://www.howacarworks.com/fuel-systems/checking-and-cleaning-an-su-carburettor

Cheers,
Jeff.
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Grand Master
Username: omar

Post Number: 1389
Registered: 4-2009
Posted on Monday, 08 January, 2018 - 02:59 am:   Edit PostDelete PostView Post/Check IP

I am with Jeff on this one.It is an easy check and well worth doing.
Top of pagePrevious messageNext messageBottom of page Link to this message

ross kowalski
Grand Master
Username: cdfpw

Post Number: 698
Registered: 11-2015
Posted on Monday, 08 January, 2018 - 05:03 am:   Edit PostDelete PostView Post/Check IP

tanluhan,

If you put a vacuum gauge on the manifold and filmed it while the engine was misfiring, that would be helpful in diagnosing a problem like this from across the internet.

I have to add, I do like the sticking carb slide theory. It's only a few minutes to pull the bells and clean and check them. Don't drop the screws.
Top of pagePrevious messageNext messageBottom of page Link to this message

tanluhan
Unregistered guest
Posted From: 58.96.231.94
Posted on Monday, 08 January, 2018 - 01:28 am:   Edit PostDelete PostView Post/Check IP

Tomorrow i will check for vac leaks, and take apart the carbs. hopefully i will see something interesting in there!

(Message approved by david_gore)
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 2808
Registered: 4-2003
Posted on Monday, 08 January, 2018 - 06:57 am:   Edit PostDelete PostView Post/Check IP

Tanluhan,

Before you do anything. download the Shadow II workshop manual from the Technical Library for free especially Chapter U which should have detailed carburettor disassembly and rebuild information for your car [I cannot be more specific as my experience is confined to pre-emission Shadow I's]:

http://rrtechnical.info/SY/TSD4200/tsd4200.htm

There is another thread currently active which illustrates the problems that can arise from not having the right information available before starting remedial work.

If your car has SU HD8 carburettors, the first thing I would be checking is varnish build-up on the piston and the bore in which it moves as this can cause problems with the air/fuel mixture if the piston does not move freely to allow the variable venturi feature of this carburettor to function as intended to give the right mixture for the operating conditions.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 493
Registered: 10-2008
Posted on Monday, 08 January, 2018 - 07:11 am:   Edit PostDelete PostView Post/Check IP

I am not familiar with Shadow2 ( chassis 32914 ),but they have a twin tailpipe , and therefore is it not possible to determine if the misfire relates to one cylinder bank ? The Carbs are I believe HIF7 as early Spirits . I have had float problems with these carbs giving rise to occasional flooding , before the float sinks completely !
If the misfire is on one cylinder bank only, then I would go for Distributor cap leads or plugs.
Mark
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 2811
Registered: 4-2003
Posted on Monday, 08 January, 2018 - 07:02 pm:   Edit PostDelete PostView Post/Check IP

Mark,

Your suggestion is fine if the twin systems are fully independent of each other.

All the dual systems I have encountered have included a balance pipe connecting both systems usually just behind the engine under the bell housing. In this scenario, using the individual exhausts may not give a valid indication.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1716
Registered: 9-2004
Posted on Monday, 08 January, 2018 - 07:22 pm:   Edit PostDelete PostView Post/Check IP

One bank fed by two carbs as well.
BTW I have replaced the floats on the SS2 but have never on the SS1 even though petrol is only used occasionally now, after many years of using just LPG the pumps stopped working needing a sort out to get working again.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 494
Registered: 10-2008
Posted on Monday, 08 January, 2018 - 07:44 pm:   Edit PostDelete PostView Post/Check IP

David, The balance pipe on early Spirits is of small diameter, and a misfire is easily distinguished from the tailpipes.My past 1981 Spirit gave me a lot of practice! Saves a lot of time taking out plugs unnecessarily. Sadly finding a duff plug on my Shadow 1 is not as easy with the single system.
Tanluhan, be prepared that even new plugs can fail quickly, I have had this experience in the past.
Mark
Top of pagePrevious messageNext messageBottom of page Link to this message

Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1991
Registered: 6-2006
Posted on Monday, 08 January, 2018 - 08:04 pm:   Edit PostDelete PostView Post/Check IP

Quote "plugged out the weakener, and plugged it with a bolt. no difference between plugged and unplugged."

did you try it unplugged? What did you plug?

You need the float chambers open to the atmosphere to test it.

What spark plugs did you fit?
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1717
Registered: 9-2004
Posted on Tuesday, 09 January, 2018 - 08:18 pm:   Edit PostDelete PostView Post/Check IP

The checking of a miss fire on a Shadow 1 cylinder can be carried out with this easy method.
First make sure the ht leads are free to remove from the top of the distributor cap.
Start engine and when miss fire is present remove distributor ht leads one at time [should have a spark from dist to lead on each one removed] until the faulty cylinder is found by the ht lead making no difference to engine sound.
Refer to the distributor timing order to locate the faulty plug, ht lead or whatever.
Tip, use insulated pliers.

BTW carb weak flat spot, carb rich rough running black smoke!

Shadow 2 close air gap to min to see and confirm module failing.
Top of pagePrevious messageNext messageBottom of page Link to this message

Robert J. Sprauer
Experienced User
Username: wraithman

Post Number: 14
Registered: 11-2017
Posted on Wednesday, 10 January, 2018 - 12:20 am:   Edit PostDelete PostView Post/Check IP

You may be surprised in what you see in a very dark environment with the engine running. You may notice arcing of the leads in certain areas.
Top of pagePrevious messageNext messageBottom of page Link to this message

Chris Browne
Prolific User
Username: chrisb

Post Number: 282
Registered: 2-2010
Posted on Wednesday, 10 January, 2018 - 11:04 pm:   Edit PostDelete PostView Post/Check IP

Hello Patrick,

Iím always interested in picking up tips about tuning of Shadow 2ís. What is the air gap you refer to in your post?
Thanks in anticipation.
Kind regards,
Chris
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 1718
Registered: 9-2004
Posted on Wednesday, 10 January, 2018 - 11:57 pm:   Edit PostDelete PostView Post/Check IP

Chris, the air gap is set between 8-14 thou or .20-.35mm.
This is adjustment is set between the reluctor tooth and the pickup limb.

When I suffered a misfire on the SS2 I closed the gap to minimum and the car was used for two years before it packed up completely on start up from cold.
BTW The minimum setting is only ok with a good distributor shaft with little run out, also when setting the gap use non ferrous feeler gauges and check all the reluctor teeth.
Hope this helps.
Pat.
Top of pagePrevious messageNext messageBottom of page Link to this message

h_kelly
Prolific User
Username: h_kelly

Post Number: 244
Registered: 3-2012
Posted on Saturday, 24 March, 2018 - 07:17 pm:   Edit PostDelete PostView Post/Check IP

Tanluhan,
had similar problem on Shadow 2 few months back, I thought it might have been the electronic ignition, anyway fitted new plugs distributor cap and rotor arm and thankfully it runs well since. I also bought new coil and ignition but haven't needed to use same just jet, thankfully.
I reckon the frost may have affected then dis cap but no obvious evidence of same.
Anyway it surprised me how a dis cap, rotor arm and new plugs could gave such radical change in performance

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: