Idle Control Valve test and replacement

[icb]

Not sure if this has been resolved or not, but the symptom stated way in the beginning - start followed by immediate stall when cold, screams huge vacuum or false air leak to me. I'd say a smoke test is in order, or at least put 1-2 psi into the intake tract and spray everything down with soapy water. Another possibility is that someone screwed up the idle CO adjustment and there's way too lean a mixture happening before the O2 sensor comes into the picture.

[Tom]

Hi all,
Just wanted to provide an update as I continue to work on the problem when I have free time.
Here is what I tried so far:
1) Starting cold engine with O2 sensor disconnected - no change
2) Starting cold engine with idle control bypassed - no change
3) Tested DME sensor and harness together per the guide provided by Tom - everything checked out. The DME frayed wires was something I did fix when I hard bought the car....so at this stage I think I can rule out the DME/DME wiring.
4) TPS testing per the the guide provided by Tom shows the TPS as working.
5) I found a doc showing some DME ECM electrical tests....went through them all and didn't find any issues. The guide states the following DME pins should have continuity when the engine is off and with ground... (pins 5,10,16,17 and 19). They all checked out ok with the exception of pin 10 and ground. Checking the schematic I don't think there should be continuity between pins 10 and ground for my car? Am I incorrect?
This is the doc: https://rennlist.com/forums/attachments ... n-test.jpg

The only remaining test I have to do is:
a) retest the AFM
b) pin 7 of the DME at startup being 0.7 per Tom (thanks again Tom!)

The AFM does have a worn out black strip when at the rest location. As mentioned before, I did try bending the arm to create a new conducting path per Clarks Garage but that did not help. It's back to where it was originally so I guess I can revisit this too.

If the AFM checks out, then is my next step swapping out the performance chips with stock chips? I don't know if the chips require a 3 or 2.5bar fuel regulator....when i replaced my fuel regulator, I put back what was in there (stock model).
Prior owner changed the fuel injectors...
Any other ideas for tests? I have not removed the intake to tackle the isv given the feedback above, but maybe there is a vacuum leak of some sort underneath the intake worth inspecting.

On a different (or maybe related note), when the car is parked/stored indoors, I smell raw fuel. Sniffing around, I believe it is coming from one of my injector seals....can the two problems be related?

I am open to any suggestions

Thanks!

Sorry I missed this. Pin 10 is the country code signal. It's not a 'ground' for the DME, but rather gets grounded as an input to the DME, to tell the DME to switch to the the alternate maps for CA, Japan, Austria, Sweden, New Zealand, and Switzerland. If yours is not grounded, that's ok.

[mikee30]

Hi all,
Just wanted to provide an update as I continue to work on the problem when I have free time.
Here is what I tried so far:
1) Starting cold engine with O2 sensor disconnected - no change
2) Starting cold engine with idle control bypassed - no change
3) Tested DME sensor and harness together per the guide provided by Tom - everything checked out. The DME frayed wires was something I did fix when I hard bought the car....so at this stage I think I can rule out the DME/DME wiring.
4) TPS testing per the the guide provided by Tom shows the TPS as working.
5) I found a doc showing some DME ECM electrical tests....went through them all and didn't find any issues. The guide states the following DME pins should have continuity when the engine is off and with ground... (pins 5,10,16,17 and 19). They all checked out ok with the exception of pin 10 and ground. Checking the schematic I don't think there should be continuity between pins 10 and ground for my car? Am I incorrect?
This is the doc: https://rennlist.com/forums/attachments ... n-test.jpg

The only remaining test I have to do is:
a) retest the AFM
b) pin 7 of the DME at startup being 0.7 per Tom (thanks again Tom!)

The AFM does have a worn out black strip when at the rest location. As mentioned before, I did try bending the arm to create a new conducting path per Clarks Garage but that did not help. It's back to where it was originally so I guess I can revisit this too.

If the AFM checks out, then is my next step swapping out the performance chips with stock chips? I don't know if the chips require a 3 or 2.5bar fuel regulator....when i replaced my fuel regulator, I put back what was in there (stock model).
Prior owner changed the fuel injectors...
Any other ideas for tests? I have not removed the intake to tackle the isv given the feedback above, but maybe there is a vacuum leak of some sort underneath the intake worth inspecting.

On a different (or maybe related note), when the car is parked/stored indoors, I smell raw fuel. Sniffing around, I believe it is coming from one of my injector seals....can the two problems be related?

I am open to any suggestions

Thanks!

Sorry I missed this. Pin 10 is the country code signal. It's not a 'ground' for the DME, but rather gets grounded as an input to the DME, to tell the DME to switch to the the alternate maps for CA, Japan, Austria, Sweden, New Zealand, and Switzerland. If yours is not grounded, that's ok.

Thanks Tom! If the AFM checks out, any other ideas on what I should look into? Since I have access to the DME and KLR, should I swap back in the original chips (since the PO put in Authority chips)? I have a picture showing the insides of the AFM from a previous attempt to address the issue - notice the worn out groove at position 0. I did try creating a new path per the instructions on Clarke's Garage but that didn't seem to help... here are 2 pics showing the view inside the AFM:

[Tom]

The AFM creates the primary air-flow voltage going to pin 7 on the DME. I would test that signal at idle (cold and hot) and report back. You are looking for something near .7vdc at idle. Any time the AFM is opened up and played with, it becomes suspect to me.

I doubt the leaky injector seal is related to this issue, but certainly a very high priority to fix.

I'd be inclined to ohm-out the O2 sensor wires to rule out breaks or shorts in the harness.

I'd also check the Full Throttle signal coming from the KLR to make sure it is not giving a false Full Throttle signal to the DME. That can happen due to a bad TPS or TPS harness issues, but I've also seen it happen due to cracked solder joints inside the KLR.

Very much doubt Authority Chips are the source of your problem, assuming they are the same standard chips thousands of others used over the years.

You could play with the FQS to add and subtract a little fuel, to see if going either way helps the cold idle. That might give a clue about whether the car is running too rich or lean to run well when cold.

Does the car run just fine once all warmed up? Trust you've tested for vacuum leaks?

[mikee30]

Hey Tom, yes it runs well when it's warmed up.
Another interesting data point I noticed today
Although the tests on my TPS show it is not defective, if I unplug the TPS and start the car it will start on the first attempt even when cold, but drop in rpm and turn off...however, if I just tap the gas a bit it will stay running without giving any more gas (contrary to when I have it plugged in - I will need to keep giving gas until the car is warmed up). In short, the car runs better with the TPS unplugged at startup. Following the TPS test mentioned in Tom's first reply eliminated the TPS as the problem, but now I am wondering if this behavior is expected when a TPS is unplugged?
I did read that some individuals have oil in the TPS sensor that causes issues....not sure if this is the case with mine, but I did remove it and turned it on it's side to see if any drops of oil would come out....none did. I did not try prying open the TPS as some suggest and just reinstalled it.
In an idea situation having some spare parts to test with would be great