944S2 Idle Air Control Valve Remove clean & test replace

Porsche 944S2 Idle Air Control Valve test, clean replace

[@rrassoc]

I really do need to say thanks for this video. You saved me a great deal of effort. Extracting my ICV didn't go as planned, but it was a hell of a lot better than the thought of removing my intake manifold. I fully expected the reinstallation to be next to impossible, but that was actually and strangely easier than pulling it out!

[@rrassoc]

I confirmed my ICV is bad. I disconnected the ICV after warming the car up. The bad idling went away. I'm happy to know this is the problem. Thanks for the info. I've ordered a new part and a ratcheting box wrench. I'll follow-up when this job is finished.

[@rrassoc]

Well this didn't go according to plan! While still loosening the bolt with my ratcheting box wrench, I realized that the screw had backed out to the point where there was no room to extract the wrench. Now my wrench is stuck in there. Lesson to others: Lubricate the screw well so you can loosen it with your fingers as in the video, or else!

[@rrassoc]

Update: I bent the hell out of the bracket and was able to extract the wrench. Whew!

[@GRhightech]

Thank you for this video I already changed my ICV because I had an erratic idle only when the engine is hot It didn't solve the problem. If anybody know how to fix this erratic idle RPM which goes to 1500 then drop to 700 RPM but never stall.

[@johncooper7242]

two things I would check. First check that the FPV fuel pressure relief valve is holding the correct fuel pressure at the rail. I think its 3 .8 barr on a 3.0L or 2.5 bar for a 2.5L engine if memory serves. If the FPR is letting by that could cause your rising rpm. Also check that you have not got a leak on the vacuum pipe and connections . Pull the vacuum pipe off the FPR valve and check you cannot see or smell petrol in the hose which would indicate the FPR is leaking. Don't forget all the vacuum connections under the inlet manifold too.

[@twistedwired]

Thanks for the explanation!

[@johncooper7242]

you're very welcome buddy ...glad it was useful.

[@epicars6902]

This part is important? And can you show all vacuum hoses for 944

[@AndrewClelland]

Thanks for this... I thought I had an issue with mine, so ordered a new one but it was showing a small gap when not connected to power... but when I removed my original factory ICV it also has a small gap when 'relaxed'. Both snap open when tested with 12v. Did your ICV here also have a small gap when not given any power?

[@johncooper7242]

good question Andrew unfortunately I cannot remember now . My feeling is It shouldn't let any air past because that air flow wouldn't be metered by the AFM and the ECU wouldn't be able to compensate my adjusting the fuel injector pulse frequency but the truth is I just don't know. Its not by any stretch a precision metering device its actually quite crude so I suspect that it would normally have a small flow when closed. I'll check my Bosch handbook tomorrow and see if it has any reference. ps I'm pretty sure that the ICV has a 5v supply I may be wrong but to be safe I would check the supply voltage or at least use a 9v PP3 battery for testing in case you burn out the solenoid coil

[@AndrewClelland]

@@johncooper7242 Thanks! One thing I did check was the voltage of the ICV plug when the ignition was on... multimeter was reading 12.36v prior to engine start.

[@johncooper7242]

@@AndrewClelland i wasn't sure if it was 12v or 5v all of the sensors are fed with 5v from the ECU . I sold my 944S2 last year and gave away over £500 of books and manuals free with it so I have to rely mostly on memory now . Is your engine running ok now ?

[@AndrewClelland]

@@johncooper7242 I just finished the install of the new ICV I received... connected everything up and so far just tested in the garage. Starts fine cold or warm, with cold start idle higher as it should be. But if I disconnect the ICV while running either cold or warm, the car now splutters and stalls. Really weird. The only thing I can think of is the TPS, but I had a new one fitted last year. Maybe though it was tuned to the old ICV, and now there is a conflict? Any thoughts? :)

[@johncooper7242]

​@@AndrewClelland From what I can remember, I discovered that the ICV is supplied with a constant 12v+ all the time that the engine is running . However its the ECU that either connects or disconnects the earth which completes the circuit for the ICV making the valve operate. So if the engine temperature sensor tells the ECU that the engine is cold ,the ECU disconnects the ICV earth thus opening the electrical circuit and de-energising the ICV solenoid which allows the ICV valve spring, to open the valve and allow extra unmetered air into the inlet. The default ICV valve position is open, held open by an internal spring.... so to close the valve the 12v+ supply to the ICV valve has to be grounded to earth internally by the ECU to complete the electrical circuit . So If the engine temperature sensor tells the ECU that the head is at normal operating temperature then the ECU will maintain a ground to the ICV which keeps the ICV valve closed against the internal spring . If you remove the electrical supply to the ICV valve then the ECU will be unable to close the ICV valve and so the engine will get too much air which will result in lumpy idle and erratic running . if the engine starts and runs as normal with the new ICV valve connected I don't understand why you are removing the electrical supply to it ? if you are still having idle and starting issues I would do a simple smoke test on the vacuum system to eliminate a possible leak and also possibly check the fuel pressure and make sure that the FPR valve is not leaking fuel into the vacuum system by removing the FPR vacuum hose when idling and check for smell of fuel

[@jesussallopez]

Thank you 🙏🏼

[@johncooper7242]

You are welcome .thank you for your feedback I hope it was helpful