Idle air control valve - Citroen Synergie

Does anyone know how the Idle control valve works on a Citroen Synergie 2.0 petrol. The revs are dropping low and sometimes stalling at junctions. I cleaned up the IAC and with it removed from its housing turn on the ignition and I can feel 3 pulses from the unit but the plunger does not move. I was told that the pulses I hear will be the stepper motor making sure it's at the start point so I won't necessarily see the plunger move. Do these only move when you start the vehicle and if so is there any way to check that it's working ok.

Reply to
John
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AFAIK this is a plunger type (standard type) ISCV which is driven out by a solonoid and retracts via a spring.

With the ignition turned on to position II the plunger should move out to a start position. -The exact position being determined by engine temperature, and trimmed by the ECU's learnt adaptive values.

With the unit assembled but removed from the vehicle, you should be able to see through it to check. (unless this is a late car with the plastic manifold)

Tim..

Reply to
Tim..

Cheers Tim. It does looks similar to ICV's that I've cleaned on other motors which have operated in the same way you say but this one just makes a click noise but the plunger does not move even if I try to pull/push it. When I cleaned and replaced the valve the engine started but would then not even idle at all. After a while it started to idle as it did before at around 900rpm but very lumpy and hunting.

What I was thinking is that when I disconnected the multiplug from the ICV the ecu reset itself into default mode which (if the ICV was not working) made it not idle at all when reconnected until the ecu had re-learned itself and was trying to keep the engine idling to compensate for the faulty valve. I'll try and get hold of another ICV and see what that does. BTW it does have the plastic inlet manifold.

Reply to
John

My limited experience with idle bypass valves is that the garages will go on for ages saying it is this component or that component and the ECU says it is the other component. However, if you just ignore them and just replace the idle valve, it generally solves the problem. I've never had success cleaning them, although I've only had the problem twice, so it isn't a particularly scientific sample size.

Christian.

Reply to
Christian McArdle

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