Citroen XM Forum

Is it the grey DIN lead you mean as I think that is for connecting a CD player? With regards, Matthew T.

That is the steering wheel controls lead.

Got nigh on bugger all done this weekend. Dad went into hospital Friday evening, Mam went in Saturday evening . . . but to two different bloody hospitals. So I've been running round like a scalded pig all weekend.

Did get one thing done though. Removed the Kenwood and replaced with a Clarion PU 9358A.

( I would have uploaded some pics but each time I tried all I got was an HTTP Error 500.0 - Internal Server Error message)

I have noticed a couple of things now it's on the road. When sat on the drive it will tickover at 1050rpm, when I drive it to full operating temperature and then pull up at a junction etc it's sat at 1400rpm. When the regulator kicks in for the suspension it drops to 1050rpm. It does this at every junction. My thoughts with the rpm are that it could be the Idle Control Stepper Motor. Is it possible to check if this is the culprit or just a case of spending the pennies? As for why the rpm would drop when the regulator kicks in . . . any ideas?

The NSF window has decided to stop working. There's power to the switch and I've swapped switches over so that's where my electrical knowhow ends.

New screen being fitted on Tuesday - £100.

Sorry that both your mum and dad are in hospital Eddie. Nothing serious I trust...

Now then, I'm going to make a big assumption here that your Si engine has the Bosch LU2 Jetronic injection with the 'flapper' AFM....

I used to have such a setup on my 205 GTi and it was a never-ending game to keep the idle good

I reckon your problem is that the idle mixture is weak and hence why there's such a distinct difference in idle between off-load an on a bit of load when the pump kicks in. Normal causes are a slight air leak somewhere south of the throttle body, a gummed up SAD (Supplementary Air Device) which effectively speeds up the cold idle by admitting more air, a maladjusted throttle switch (contacts not closed at idle) or a weak main spring in the AFM. Go for the air leaks first. A favourite on the 205 is a perished pipe to the distributor vacuum advance or a punctured vacuum advance diaphragm on the distributor. That last one can keep you guessing for months... It did me...

There is no idle stepper motor, just an idle speed screw on the throttle body and good idle control is critically dependant on there being no air leaks at all anywhere, even tiny ones. The LU2 is so sensitive to them it's unreal.

If all is good then suspect the AFM main spring has got weak over time and allowing the flap to open too far and weaken off the mixture. It can be reset but a CO meter is essential to do this. It can't be done by ear...

Also, check the ignition timing too. That's critical..

If you haven't got LU2 then just ignore everything I've just said...

It's the Magnetti Marelli system.

Eddie nuff wrote:It's the Magnetti Marelli system.

Ahh, bad assumption on my part then Eddie... And a waste of typing!

In that case I can't help at all as I can confidently say I know nothing of that system at all...

I'd still look for air leaks though and pass a critical eye over the MAP sensor...

It sounds to me like the ic valve is dead tbh or an air leak, the valve should keep constant idle speed depending on load and engine temp etc if you can get different idle speeds hot or cold or if adding a load to the engine alters the idle then the valve isnt working, you can try taking it out and giving it a spray with GT40 (not WD40!) and try it again but if its the motor thats died rather than the valve itself gummed up it wount have any effect and you will need a new unit.


D

There are no air leaks - or, more to the point, there are no obvious air leaks.

The engine idle is smooth at a constant 1050rpm or 1400rpm depending on circumstances. Apart from this the engine runs very well indeed.

Check the idle control valve actually has power to it. I've known the 12v go on a Renault, which caused low idle speed, but maybe the throttle rest position has been adjusted to compensate.

Try plugging the idle bypass and see what the static idle speed is. You probably need to set that with the ECU in default mode, possibly by disconnecting the temperature sensor.

There's a bit of confusion over which system is fitted. When I bought the car I was told it was Magnetti Marelli, someone else I know said the same. I've spoken to the guy who maintained it for 10 years and he says it's the Bosch Jetronic system. He said the first point of call would be to check the throttle potentiometer and the throttle switch as the owner refused to do it as it cost too much.