Idle Trouble...

[neil.b]

Been getting this on and off since I got my car, thought I'd throw it out to everyone to see if you have any suggestions/suspicions....

Each time my car goes in for some tweaking/servicing, it comes back smooth as silk - starts up sweetly and ticks over very smoothly. Then gradually, after a few more hundred miles it starts to get rough again.

Its been about 1200 miles since the 6k service and now the car is spluttery and clanky when starting up and cold idle is like russian roulette - varies between 500 and 0 rpm, resulting quite often in stalling when backing out of the garage.

Other mechanical issues at the moment (I figured they might be relevant);

1 - slight oil leak from the oil tank (either the valve where the sensor goes in, or the drain valve underneath)
2 - slightly blowy exhaust
3 - tendency to piss itself after a spirited drive

Re. 1 & 2 water and oil levels are fine, oil has been slightly over the max mark since the last service (when temp is >60C)

Anyone got any thoughts?

Thanks

[NCE 61]

Low Idle speeds/stalling can be any one of the following:-

1/valve clearences closing up,if the dealer just adjust the tickover speed they could be covering up this problem.

2/Lambda sensor giving bad signals, the only way to check this is via the TVR diagnostic software ie at dealers.

3/Throttle body spindal bushes wearing, causes un-even running.

4/Poor quality of fuel do you use 98/Optimax?

Nick

[neil.b]

NCE 61 said:

Low Idle speeds/stalling can be any one of the following:- 1/valve clearences closing up,if the dealer just adjust the tickover speed they could be covering up this problem. 2/Lambda sensor giving bad signals, the only way to check this is via the TVR diagnostic software ie at dealers. 3/Throttle body spindal bushes wearing, causes un-even running. 4/Poor quality of fuel do you use 98/Optimax? Nick

Cheers Nick

1 - this is what I'm concerned about - even I can adjust the tick-over speed but its the fact that it keeps drifting out that makes me think there's something else going on

2 - the Lambda sensor has been mentioned before but it was checked at the service and no report of a problem

3 - sounds ominous - guess this is one for the mechanic? Is it easily checkable?

4 - try to, 90% of the time I'd say. What happens if you mix fuels? (95/97/98) Is that bad?

[Bitter'n'twisted]

I had similar (poor running / stalling while reversing out of garage in the morning etc).

Mine was the throttle bodies.

They tried adjusting things at the garage but (as after a few days better running it returned to poor running), in the end the throttle bodies were sent back to TVR for re-bushing or something.

It then ran ok.....for a short while, so I took it back again and the mechanic said 'I knew it'd do that after they had renewed the bodies'.

So he set it up again and it has been spot on since (3000 miles).

[NCE 61]

neil.b said:

NCE 61 said: Low Idle speeds/stalling can be any one of the following:- 1/valve clearences closing up,if the dealer just adjust the tickover speed they could be covering up this problem. 2/Lambda sensor giving bad signals, the only way to check this is via the TVR diagnostic software ie at dealers. 3/Throttle body spindal bushes wearing, causes un-even running. 4/Poor quality of fuel do you use 98/Optimax? Nick Cheers Nick 1 - this is what I'm concerned about - even I can adjust the tick-over speed but its the fact that it keeps drifting out that makes me think there's something else going on 2 - the Lambda sensor has been mentioned before but it was checked at the service and no report of a problem 3 - sounds ominous - guess this is one for the mechanic? Is it easily checkable? 4 - try to, 90% of the time I'd say. What happens if you mix fuels? (95/97/98) Is that bad?

Mechanic should be easily able to check if the throttle body spindle bushes are starting to wear although you will feel it when driving the car particually between 2-3000 RPM as it will feel very un-even.

I always try and use 98 or Optimax, although they should run OK on 95 so mixing should not be a problem.I had a bad tank full of petrol recently and suffered stalling & low speed misfire when cold all was cured when I re-filled at my usual petrol station.

Nick

[slikk]

Clean the stepper motor. It should be done regularly to avoid a lumpy tickover and only takes ten minutes, worthwhile for no other reason than to eliminate it from the equation.

[jam1et]

The speed 6 only uses stepper motor for heating controls doesnt it? Its the V8 which uses one for idle control. Please correct me if I'm wrong though.

Edited for crap spellin'

>> Edited by jam1et on Tuesday 18th May 15:40