Crazy Eddie

Hope it helps ....

Crazy Eddie

BTW
Here is a thread that was started a while ago that I wanted to bridge in case others have the same problem.....
https://rennlist.com/forums/944-turb...any-ideas.html

spanky

Ok Eddie it is now time to get this dammed car out onto 280 and give her a real road test. Say to LA and back!!

mikeyoman

We had similar issue with the cruise control on a friends 944S2. Couldn't be bothered to fault find the circuit, and in response to a couple of other posts on here about dry joints, just resoldered every joint on the board and never gave any more problems.
Friend was well impressed but I did give RL the credit for the idea

Doyle623

I'm having an issue where the car has a low idle (around 500 rpm) until the car is warmed up. Once fulled warmed up (middle line on temp gauge), it idles perfectly. I found that the wires going to the idle control valve were frayed and all three wires going to the ICV were touching, so I soldered in a new connector. Before putting it back together, I tested the valve and it works as it should when, but have the same low idle issues. Would you guys agree that these wires touching would likely short out the circuit in the DME? I'm thinking about trying to solder in a new transistor.

odb812

Have you tried electronically disabling the ISV while it's idling cold to see if there's any difference in idle(ie: maybe the ISV is bypassing some air, but not enough)? You can disable the ISV by shorting two connections on the diagnostic port in the driver's side of the engine compartment.

Doyle623

I did try that and it doesn't seem to make a difference...

Zeff

I'd suggest doing the full idle setup on the Lindsey site first and then look for wiring if that doesn't fix your issues.

odb812

How about leaving the ISV harness accessible and measuring the volts across when the engine's cold and when it's warm? It could be the block temp sensor is not functioning properly and telling your working ISV to do its job.

Doyle623

So I tried setting idle per Clarks-garage website and didn't see a change in cold idle. I then plugged in a different working ICV (I checked by putting a ground wire to the middle post and then going back and forth with outside posts with a positive wire and it switched back and forth as it should). Started again and no change. I then unplugged the idle control valve and put power to the posts to open it all the way before starting the car and the car idled very high at around 2k RPM. I closed the valve back up because I expected the valve to be working only when the idle is low and when I tested the power coming in, I got 0.4 V to one post and 0.8 V to the other one. A side note, I recently replaced the temp sensor (blue one).

Tom M'Guinn

Since you have a spare ISV, try this. With the car fully assembled, pull the electrical connector off the installed ISV and plug the connector onto the spare ISV (just hold on to the spare ISV without hooking up any hoses etc.). Then start the car and look inside the spare ISV port to see if the valve ever moves. Rev the motor etc. and try turning the a/c on and off. If the tested ISV valve doesn't move at all, then either the DME is fried from the short, or there's harness problem. If it does seem to move appropriately (opens up for a/c etc.), then the DME circuit is probably good.

Cyberpunky

Had an issue with my car when I first got it and my mechanic worked out it was the KLR and without replacing a bunch of stuff at my expense(which was great). Took a few weeks to get to the bottom of it, but he saved me a packet of money by diagnosing it properly. Even the company who rebuild the KLR and DME's said it was weird, as although they could test that it was clearly faulty, they couldn't actually work out what was causing it. All the posts I read back then, none mentioned the KLR so would never have thought of that being the culprit. Great to have someone who knows these cars to help at times like that. Anyway glad you got it sorted and can enjoy your car now
peace
Cyberpunky

Doyle623

I used the method that Tom suggested and as it turns out I'm not getting a signal to the ICV. I assume, besides a wiring issue, it would have to be the DME or KLR.

Tom M'Guinn

The outside terminals of the ISV (the ones that get power from the DME to control it) are connected to pins 33 and 34 of the DME. You can check the continuity from those pins on the DME connector (in the foot well) to pins 1 and 3 of the ISV connector. Assuming those show good continuity, and Pin 2show good continuity to ground (and assuming the ISV used to test is good) then that would leave the DME as the culprit. You could test the DME by carefully putting insulated alligator leads on pin 33/34 and check on a multi-meter to confirm those pins are getting no voltages regardless of a/c, revs, cold, etc. Easiest way I've found to get at the DME pins while the harness is connected it to pull the covers off the DME and attach clips to the posts behind the main connector (i.e., the metal posts that get soldered into the board) -- just make sure the clip doesn't short to any other post... ECUDocs in Florida can fix it up if you fried the ISV circuit or, if you're an electronics type, you may be able to replace the parts in the ISV driver circuit yourself...