My 1992 1360cc Citroen ZX - stalling, rough idle etc.

[c4koh]

Wondered if anyone can help.

The engine runs fine when cold, but when warmed up, starts to idle erratically, stalls, and cannot maintain a rev range (e.g. hold the throttle at a position, the engine lurches around).

I have replaced the spark plugs, ECU, coolant sensor (x2 - one for the guage, one for the ECU I suppose), Lambda sensor, fuel injector [it's a monopoint injection].

(Thankfully all of the above off a donor car!)

I do not think it's spark related: when cold, or when warm and being 'good' the engine revs fine and pulls as good as it should.

The symptom seems fuel-related: it's not metering the right amount of fuel, or related to a sensor to meter this...

I'm looking to replace the entire unit [Bosch Monopoint MA3.0], as this includes the fuel-pressure reg. and the throttle position sensor, both which can't be changed independently (easily).

If anybody has any other clues to check, or had this before, would appreciate the feedback...

[wildoliver]

I had something similar on a 205 that I had with the same engine. It turned out to be head gasket.

If yours turns out the same i still have a brand new one in wrapper.

[I Cooke]

If that model has an idle air control or SAD then it might be worth looking at that. They can get gummed up and stick causing irregular idle speeds or stalling.

[that daddy]

I Cooke said:

If that model has an idle air control or SAD then it might be worth looking at that. They can get gummed up and stick causing irregular idle speeds or stalling.

If it turns out to be this unit dont do main dealer,go bosch agent,(cheaper)

[c4koh]

Thanks for the suggestions.

Don't think it's the idle control motor: the rough conditions happen throughout the rev-range [e.g maintaining throttle at a particular opening, revs up and down]... tip of throttle isn't touching the idle control motor at this point, so I'm ruling that out...

I also tried a new fuel injector: same problems.

I'm left with one more thing to check - the throttle position sensor... I'll double-check the lambda sensor after that [check the voltages] and if still no luck, must be a new fuel-injector unit...

And of course, I never go to Citroen for anything - my local motor factor helps instead [at about 1/5 of the price!]