Ongoing idle problems...
Discussion
Posted a while back on the 'S' forum regarding a problem with idling on my V8S. Thought things were sorted, but now appears not!
On initial start up things are fine. Go for a good run/blast and get things up to full working temp, then stop for 10 minutes, for whatever reason.
Upon re-starting car it will not idle smoothly, if at all. It relly wants to die as the revs drop very low, and sometimes does. A blip of the throttle catches it and it revs high (2000 rpm) for few seconds, then settles to a very rough/lumpy idle at about 750/800 rpm.
Have cleaned the stepper moter numerous times, with a squirt of WD-40 too... still happening!
Anyone had similar problems? Any possible solutions?
On initial start up things are fine. Go for a good run/blast and get things up to full working temp, then stop for 10 minutes, for whatever reason.
Upon re-starting car it will not idle smoothly, if at all. It relly wants to die as the revs drop very low, and sometimes does. A blip of the throttle catches it and it revs high (2000 rpm) for few seconds, then settles to a very rough/lumpy idle at about 750/800 rpm.
Have cleaned the stepper moter numerous times, with a squirt of WD-40 too... still happening!
Anyone had similar problems? Any possible solutions?
Pete
Sounds a little like a leak in the inlet system, after the throttle butterfly. Maybe the manifold gasket or maybe there is some vacuum pipework with a leak in it. Idles OK when the mixture is rich, (cold), but won't idle when hot, (lean mixture). Idling results in a high vacuum in the inlet and will search out leaks. A big problem on a carburated engine, not sure how it will affect a fuel injected engine but I reckon lumpy idle is most likely.
Probably worth checking.
Maybe drip some redex or similar around the manifold gasket, if you get some blue smoke in the exhaust you found a leak. Used to do this on the mini, I guess your S is pre cat so I imagine that is OK?
Will you make the run this weekend? Nearly 2000 miles on the T350 now so I might be able to keep up.
Cheers
Bob
Sounds a little like a leak in the inlet system, after the throttle butterfly. Maybe the manifold gasket or maybe there is some vacuum pipework with a leak in it. Idles OK when the mixture is rich, (cold), but won't idle when hot, (lean mixture). Idling results in a high vacuum in the inlet and will search out leaks. A big problem on a carburated engine, not sure how it will affect a fuel injected engine but I reckon lumpy idle is most likely.
Probably worth checking.
Maybe drip some redex or similar around the manifold gasket, if you get some blue smoke in the exhaust you found a leak. Used to do this on the mini, I guess your S is pre cat so I imagine that is OK?
Will you make the run this weekend? Nearly 2000 miles on the T350 now so I might be able to keep up.
Cheers
Bob
Hi Bob,
Thanks for the ideas, I've been running out of them... very frustrating!
I understand what you suggest and will do some investigation. Funny thing is the idle seems fine when hot until the engine is stopped and then started again.
I hope to make the run next Sunday. Will have to get a few miles on the car before then to see if it's in suitable health.
Thanks for the ideas, I've been running out of them... very frustrating!
I understand what you suggest and will do some investigation. Funny thing is the idle seems fine when hot until the engine is stopped and then started again.
I hope to make the run next Sunday. Will have to get a few miles on the car before then to see if it's in suitable health.
Could possibly be same fault I had (Griff 4.3) - idles fine until warm then up and down, almost stalling before revving up to 2000 rpm, then dropping back down and so on. Eventually traced to the position of the ignition amplifier, mounted on the side of the dizzy on earlier V8s (the later Griffs/Chims have the amp mounted on a heatsink at the top front of the engine (above/in front of RH rocker cover). Moving the amp from the dizzy to a custom ally plate bolted to the chassis below the exhaust manifolds cured the interference problem. This problem appeared suddenly, for no apparent reason, and was nothing to do with the usual suspects (stepper/water temp/air flow meter/throttle pot etc) Absolute pain in the 
Good luck anyway!!
Good luck anyway!!Another one for you - well, two actually.
1) Lamda sensors - I had similar symptoms which were cured when these were replaced - does the S have these? ('scuse my ignorance
)
2) Clogged fuel injectors - again after similar symptoms the nice chaps at Austec tested them using their shiny new ultrasonic cleaner. They were all in a bad way, one so much so that it had to be replaced. The rest were cleaned and the spray pattern checked. All has been silky smooth ever since.
1) Lamda sensors - I had similar symptoms which were cured when these were replaced - does the S have these? ('scuse my ignorance
) 2) Clogged fuel injectors - again after similar symptoms the nice chaps at Austec tested them using their shiny new ultrasonic cleaner. They were all in a bad way, one so much so that it had to be replaced. The rest were cleaned and the spray pattern checked. All has been silky smooth ever since.
Wow, more suggestions... thanks guys. Looks like I'm going to be busy over the next couple of nights! 
Will test/check whatever I can with my fairly basic mechanical abilities, but there are some things here I don't think I can check myself. Might have to give the chaps at Peninsula a call.
No Lambda sensors, so thats an easy one to eliminate. Will look carefully for any inlet leaks. The suggestion about the ignition module is an interesting one. Not sure how to prove/disprove this as a problem?
Will keep you posted.
Will test/check whatever I can with my fairly basic mechanical abilities, but there are some things here I don't think I can check myself. Might have to give the chaps at Peninsula a call.
No Lambda sensors, so thats an easy one to eliminate. Will look carefully for any inlet leaks. The suggestion about the ignition module is an interesting one. Not sure how to prove/disprove this as a problem?
Will keep you posted.
My ignition amp problem was something supposedly unheard of on a TVR before, although it must have given Land Rover problems for them to resite the amp on later engines, it was only when I took it to Camco in Warrington that it was diagnosed. Its probably a long shot but worth bearing in mind if all else fails.
Lets hear a big cheer for Lucas electrics...
:silencesmiley:
Lets hear a big cheer for Lucas electrics...
:silencesmiley:
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