My 2000 Carisma is not well at all

I'm in the UK and I've got an X-reg (2000) Carisma 1.8 GDI Equippe Auto (4G93 engine) that's playing up.

Symptoms are:

When starting from cold, instead of just sitting at a fast idle the revs go up to about 2500 then drop to about 800, then go up, then go down, up, down etc., etc., oscillating between the two values for about 20 seconds, then it settles to about 1000.

Putting it into either "D" or "R" the revs drop right off and it almost stalls. Sometimes it does actually stall.

On moving off, the car accelerates to the point where the auto box wants to change gear but during the change the engine races (on a manual box it would be like putting your foot down on the clutch but without lifting your foot from the accelerator) so that there's a jerk as it engages the next gear.

When the engine reaches normal running temperature most of these things disappear and the car drives OK. The only thing that remains at normal temp. is the stalling. Sometimes, waiting at traffic lights for instance, I'll have the car in Neutral. When the lights change and I put it back in gear, the revs drop off and it almost stalls - sometimes it does stall. And sometimes, when approaching junctions, it'll stall before it comes to a stop.

It's done 50,589 miles and had the transmission fluid dropped, box flushed out and new fluid in, along with cambelt change and everything that should have been done on the 54,000 mile service, nine months ago at 45,490 because the dealer said that it was 54,000 or 5 years, whichever came first.

I rang a mechanic today who's going to have a look at it on Wednesday, but describing the above to him on the phone, he reckons it could well be the Idle Control Valve Stepper Motor - what do you guru's on here think?

Cheers,

Fred

Reply to
Fred
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Hi Fred I have a simular problem with my Carisma, (2001, 50,000 miles) and some times the engine management light stays on. I have been told the same thing, the throttle stepper motor is sticking. Apparently they get dry and need lubricating, although I have not had time to take it apart to find out for sure. Mine only does it occasionally but it can burn out the coils that operate the motor.

Reply to
9points

It could well be the Idle Control Valve Stepper Motor, and any of a variety of other things too.

The FIRST thing to do is get an error code read out to what the ECU thinks is the problem.

Cold surging is also caused by

- vacuum leaks

- fuel gum in the throttle body

- dirty air cleaner

- MAF connector needs cleaning.

It's generally not caused by a lack of fuel pressure. A bad or disconnected coolant temp sensor makes for hard starts and not surging.

Engine racing between changes might be

- Control Valve Stepper Motor

- fuel gum in the throttle body

Might be related to the O2 sensor, see

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for a decent discussion on how this affects mixture. If your fuel economy has deteriorated, its likely the O2 sensor.

Point is the ECU when cold is initially running in open loop, and when it warms up, moves to closed loop. The Carisma likely has a heated O2 sensor.

Try this: when the engine is cold, disconnect the battrey for 30 seconds to reset the ECU, then see if the surging continues. It will come back after a while anyway, but if it goes away, then the problem is a sensor and not the Control Valve Stepper Motor.

Disconnect the Control Valve Stepper Motor and see what happens. The engine wont surge íf that's the problem.

Reply to
Stewart DIBBS

Oh well, at least it looks like his telephone diagnosis may well be right then. And I forgot to say earlier that my engine management light sometimes stays on as well.

I suppose these stepper motors cost about as much as a kidney - nothing's cheap on these bloody cars is it? Ironically, we didn't have a lot of money when we bought the car and one thing that tipped us in favour of it, given the extortionate price of petrol, was the *supposedly* fantastic mileage you could get from the GDI engines but I've never had better than about

33-35mpg.

I think I might just get it repaired and sell the damn thing. Good luck with yours.

Fred

Reply to
Fred

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