So the problem has been there from the day you reassembled the car, correct?

Did you check that your throttle cable is not binding? I suppose it would be possible for the idle switch to be closed with the throttle mis adjusted.
If you kill the idle by letting the clutch out with the car in gear will it pop right back up to 3000?
Are you sure there is not a difference in the ISV from early to late (alum/plastic) intakes? The vacuum circuit is different on both cars.

Have you checked fuel pressure?

Have you done a DME "adaptation" ? In your case this is tricky because the car is supposed to be at idle and you effectively do not have an idle...

 

I have not checked the fuel pressure. I can though. Is there a test port for that? I do have a gauge. what should base pressure be? When FPRs fail i always assumed they would fail causing lower pressure not higher which would cause a stall. also the throttle cable does not appear to be binding. Yes i would say the issue has been since the car has been put back together. I am not sure what you mean by difference in ICV generations. I put the original icv back in the car after i tried the swapped one. As for the clutch test i am not sure i understand correctly. With the car running and in gear and it idling at 3000 rpms i just let the clutch out slowly to let it roll?

 

Yes the driver side fuel rail has a port on the lower side close to the distributors.

Do you have the factory manuals? They are posted widely, there is a thread on this forum with many links. The procedure and specs for the test and other trouble shooting are within.

Yes what I meant is to intentionally bog the engine down to see if it rebounds to the 'wrong' idle. let the clutch out in gear (brakes on if needed) as though you would stall the car but then recover it with the clutch in at 1k rpm. Does it shoot right back to 3k?

You said your car was in boxes. Maybe you have incompatible intake parts. You are aware there is a plastic and alum intake each with some parts that differ. Could you have a mixed up group of parts? Review PET for changes from early to late.

 

And - have you either checked the resistance/voltage of the AFM or adjusted its 'wiper' ? Here are a few of the checks from the factory manual...

 

Update. Yes if i release the clutch it will accelerate back up to the 3000 rpms. Also i play with the connection to the air flow meter and the idle went back down to where it was supposed to be, however, now that it idles normal with the connection to the airflow meter established it spits and back fires and will not let me go past 1/4 throttle to accelerate. It was in boxes due to a cam oiling issue. but all of the pieces were originally running on the car. Although i agree you could be correct, i didn't buy anything individually. So i believe you are correct to check the AFM. my question on fuel pressure is, wouldn't that still show as an issue even with the afm disconnected? and why would the car accelerate while the afm is disconnected? Maybe a limp mode fuel map?

 

Also, AFM is out, it looks a little rough. And i am missing the metal clip that goes in the pigtail for the afm connection, and the rear clips on my air box are broken. Like i said, its a driver, not a show or collectible. i just want to get it running solid and enjoy it. So would it be better just to buy a short ram/cone filter kit than to buy a replacement air box? I will try to figure out testing those resistances to see if them afm is any good still. Thank you again for the help and info so far.

 

Are you aware of the technical service bulletin that involves zip tying the electrical connection to the AFM? upload a pic of the connector.

 

And yes, the majority of the sensors on motronic do have stored values that the computer defaults to if it senses a failure as a limp home mode. You should really read through the entire section in the factory service manual to wrap your head around the system

 

I found a technical bulletin for 89-90 models talking about issues with the pigtail for the maf. sure enough i took the protective boot off and two wires were bare and touching. I did a quick test fix with some electrical tape and it worked for a minute and the car does run much better but it now surges between 1000-1500 rpms. Can i buy a whole pigtail replacement or am i stuck trying to repair mine? I am wondering if the worn wire although separated might be contributing to the surge.
https://rennlist.com/forums/964-foru...rness-mod.html

Edit* is the pigtail for the 944 the same as the 964? the know the air flow meters look similar but the resistances are different but if the pigtail is the same then that might be easier to find.

 

I ordered a new connector which came with a new clip and boot. I put the link below. I need to find a crimping tool small enough to crimp the new pins on but my plan is to replace the connector.

https://www.milspecwiring.com/BOSCH-...KIT_p_562.html

 

Nice find and fair price. Those wires are presumably not smaller than 20AWG, wouldn't a standard quick connect crimp tool handle it?

 

I am going to try one tomorrow. But if not they make a special "Pin Crimping Tool" that ill order.

 

I went with the $17 open barrel crimping tool from amazon. It worked quite well. the new AFM connector is installed and fits perfectly. It no longer screams at 3000 rpms at idle, And it fires right up at cold start. However now that is fixed, once the car warms up it idle surges between 1200-1500 rpms.

 

I read your post with a hope I could solve an idle problem of my own. Just posted the details in a new thread. Sounds like you have solved your issues and I'm going to re-examine my AFM as well.

 

I do still have an idle hunting issue from 1200-1500 rpms. I am still leaning towards the AFM though. I am going to pull it out and clean it again.