tick over problem

[mac123yre]

Hi chaps I have another problem you may be able to help with, when the car is warm the revs on tick over suddenly drop to either stall the engine or very nearly, I have to feather the throttle a bit to coax the revs back up, any ideas, my first thought was air getting in but seems ok.

[ed_crouch]

Does this happen when the fan cuts in? Could be weak mixture. Do all the usuals like check throttle pot voltage between green and red with ignition on. Should be 300 - 350mv. If not loosen screws and adjust. Check idle CO. If you can get it under 4% you're a better man than I... What speed does it idle at when its idling well?

Is the idle sound as a pound otherwise, or is it always a bit poor?

[honestjohntoo]

Be good to know what engine and system you are running. I'll assume 3.5 flapper. Have you tried adjusting the idle control screw? Does it even make a diference? If not the idle air gallery is blocked OR you have other air leaks that swamp the idle control. Is the breather system and gallery clear. Plus the other suggestions from Ed.

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[ROOODBOY]

I recently bought a 350I which suffered a similar problem, it was almost cured once I changed the spark plugs.

It still has slight idle issues but I think it's to do with an exhaust blow I have (which I plan to fix as soon as I have a free and dry weather day!), so it might be worth checking the exhaust too..?

[timtenor]

I have a similar problem - car stalls when clutch is depressed, hunts during warmup, runs lumpy and very rich.
I've been told to replace the coolant temperature sensors. There are two of them. One sends info to the ECU. If it's broken the ECU thinks the engine is cold and floods it with excess fuel or causes the engine to run very rich.
Sensors are available from Rimmer Brothers 01522/568000 and are fairly cheap. I think they are the same as fitted to the Rover SDI.
You could also try calling V8 developments at 01775/750000
Happy hunting
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[mac123yre]

thought I had cured it today the low tension lead was to close to the HT leads thus cause an ark to jump, moved it and it seems to have cured it but hey presto its back but not quite as bad, I am going to try new HT leads, the CO2 setting was also a mile out.

[350zwelgje]

Cleaning of the CO-adjuster (take it completely out, clean, reinstall and adjust) can be of help. At least it did in my case. Another symptom was that idle adjustment at the plenum had no effect, after cleaning all back to normal and no problems since. All on a flapper 350i.

Rob

[honestjohntoo]

Is the problem solved yet? if not, from the following:

mac123yre said:

but hey presto its back but not quite as bad ..... the CO2 setting was also a mile out.

So, changing the amount of air coming to the engine via the CO adjust control made a small difference, therefor go back to this:

honestjohntoo said:

Have you tried adjusting the idle control screw? Does it even make a difference? If not the idle air gallery is blocked OR you have other air leaks that swamp the idle control. Is the breather system and gallery clear. Plus the other suggestions from Ed.

Apart from CO, what else did you find?

[mac123yre]

I moved the HT leads apart and sprayed with WD40 and it seems to have cured the problem so I think new leads are needed.