alternative to 86 ICV

[junkman300SD]

I'm suspecting my ICV is toast. Bad cold idle, no vibration from the valve. I'll test the switch, pull the ICV etc this weekend but what are the alternatives?

My objective is to get by and keep driving until my shop is finished and I can do more properly.

[GH85Carrera]

Pull the ICV, and hose it down with carb cleaner, and blow it out with air, and look to see if it is clean inside. Hook it back up, and see if it vibrates when the engine is running. If not, check that the connectors are producing voltage. It is really easy to remove, as it is right in front.

[FA-18C]

Junk - agree with GH85 - easy to pull, use a good carb cleaner and very thoroughly clean the ICV. When you think you are done, clean it again. When you rotate your wrist back and forth, you should feel and hear the valve going back and forth. To make sure the switch is not toast - get a 9V batter and connect the positive lead to the center pin, and then alternate the negative lead to the two outboard pins. The valve should click back and forth. I also used some electronic lubricant in the valve and cleaned the pins.

As I am learning, cold idle can be impacted by overly rich setting, vacuum leaks, AFM, fuel filter and potentially the FPR. My car sat idle for 13 years, I have changed the fuel tank strainer, check valve, adjusted the sweep on the AFM, replaced the fuel filter (again), new injectors, and cleaned the ICV twice. Made huge progress. I suspect my issues were a little bit of each

[junkman300SD]

I'll do all of the above.

For the forum, IF (and only if) it's bad, what are the alternatives?

[mysocal911]

Originally Posted by junkman300SD

I'm suspecting my ICV is toast. Bad cold idle, no vibration from the valve. I'll test the switch, pull the ICV etc this weekend but what are the alternatives?

My objective is to get by and keep driving until my shop is finished and I can do more properly.

1. Test the winding resistances - 20 ohms from the center pin to each of the outer pins
2. Use this test procedure at post #20;
Bench testing Carrera Idle Control Valve

If the above checks OK, then the DME ECU outputs may be the problem.

[911obgyn]

Volvos and mercedes used the same ICV
Search the bosch part#

[Matt at Pelican Parts]

I have found that soaking the valve end of the IAC overnight in some sort of degreaser/cleaner works great to break the gunk up.

-Matt

[mysocal911]

Originally Posted by junkman300SD

I'll do all of the above.

For the forum, IF (and only if) it's bad, what are the alternatives?

Yes, that's it!

[junkman300SD]

This thing has a lot of little and not so little things to address. That said, it's the coolest and most fun car on the road - even before the trans gets sorted, AC fixed, suspension tuned etc.

It may have an un-fused parasitic drain but I need to confirm that my meters are accurate and that's another thread. (Relatively new battery died with only 20 ma measured drain still there with all fuses removed. )

[917_Langheck]

Originally Posted by junkman300SD

It may have an un-fused parasitic drain but I need to confirm that my meters are accurate and that's another thread. (Relatively new battery died with only 20 ma measured drain still there with all fuses removed. )

Presumably all of the ones in the engine bay too? Easy to forget about those.

[junkman300SD]

Originally Posted by 917_Langheck

Presumably all of the ones in the engine bay too? Easy to forget about those.

Yes, all fuses were removed. And I note that 20 ma isn't supposed to be enough to drain the battery unless it sits for a long time. I forgot the calculations but first it wouldn't turn over after a week then it dropped to now where it won't crank after a few hours. (I use "crank" to mean the starter won't turn the engine over - which is the correct use of the term crank.)

It always starts when it cranks.

[mysocal911]

Originally Posted by junkman300SD

Yes, all fuses were removed. And I note that 20 ma isn't supposed to be enough to drain the battery unless it sits for a long time. I forgot the calculations but first it wouldn't turn over after a week then it dropped to now where it won't crank after a few hours. (I use "crank" to mean the starter won't turn the engine over - which is the correct use of the term crank.)

It always starts when it cranks.

Assume a 70 Ahr battery with a 20 ma draw, and at least 1/2 capacity (35 Ahr) remaining for a start;

Time to 1/2 capacity = 35 Ahr / .02 amps = 1750 hrs = 73 days = 2.4 months

[gumby]

Heidi and Franny youtube series explores this
https://www.youtube.com/c/HeidiandFrannysGarage/videos

[junkman300SD]

Sometimes you get lucky. I pulled the valve and shook it. No discernable movement so I sprayed with brake cleaner and blew it out. Applied voltage and it moved.

Reinstalled and measured voltage at the plug. There was full battery voltage on 1 leg. I plugged it in, started the engine and it idled better than it has in the last 2000 mi (length of my ownership).

Unfortunately, it's 60* out so the good idle may truly be luck. I'll know tomorrow morning.

Edit: cold idle goes up and down then settles in. There is something small that needs to be addressed. The car does smell rich but I don't have a meter and I'm only making SWAG not a diagnosis. This is the kind of thing where you have to decide to fix it by getting into the details. I'll have to look into ways to accurately set the mixture and, and, and.

Gauges used to be expensive but I expect that has changed now that these cars are old technology. Even OBDII scanners used to be expensive and big. Now the cheap ones are a few dollars and they run on your phone. Of course the expensive ones do more.