16 Valver's - beware of aftermarket ICV's!

[NCGermerican]

Hey all - I wanted to make a specific post about aftermarket ICV's for the 16v cars. As you know, we don't have an idle adjustment screw like the 8v cars - the DME controls the idle through the ICV, which is specific to our cars.

Background - I've had my 1987 S since 2021. When I purchased the car, I didn't have a lot of experience with 944's and pretty much just replaced everything I could. My mentallity was "if i just replace everything, I shouldn't have any issues!" Given the cost of the Bosch ICV, I went with an aftermarket unit. Needless to say, the car had intermittent surging idle issues as well as would sometimes stall when coming to a stop (once pushing in the clutch).

I dealt with this problem for over a year. I have the DME service manual and went through EVERY test I could (except those that required an oscilloscope) and everything checked out as it should. I replaced plugs multiple times, 02 sensor multiple times, multiple smoke tests, etc. This issue caused me to abandon a completed S2 intake swap project (went back to the original intake setup) and honestly, it was the catalyst for me to purchase my 951 - with the goal of getting rid of the S.

So, as luck would have it, I purchased (what I thought) was the actual Bosch ICV (over $600) for my 951. However, what arrived was a Bosch unit for a 16v. I was about to return it when I thought "what the heck - let me install it on my S and see what happens."

All of my idling and stalling issues were IMMEDIATELY fixed. The issue all along was the brand new aftermarket ICV. Normally I would say it was an isolated incident, but @michael2e went through the SAME scenario - new Bosch unit fixed the issue after (in his case) trying MULTIPLE, aftermarket ICV's.

I'm inclined to think that ICV's are a lot like motor mounts - better to spend the extra money for the genuine part and save a lot of money and TIME in the future.

I hope this helps one of you out there that may have similar issues.

[sefeing]

Great to know, At 114k, im sure mine could use a good cleaning - did you try that prior to replacing it? Knowing it's not a small job to get to the valve, I'd be hard pressed to just swap a new one in but I've heard they can be cleaned up.

[NCGermerican]

Great to know, At 114k, im sure mine could use a good cleaning - did you try that prior to replacing it? Knowing it's not a small job to get to the valve, I'd be hard pressed to just swap a new one in but I've heard they can be cleaned up.

Unfortunately, I didn’t clean the original. I was a novice to 944s at that time and my mentality was that a brand new aftermarket unit was better than a cleaned original, with 95k miles on it. I was wrong and it cost me over $600 for a new Bosch unit. Live and learn!