Idle/ECU ***SPLIT from setting idle***

[krs09]

I have been following this thread because we seem to have some what similar problems. I have bee playing with my idle and the one thing i have been checking is my ECU (behind driver seat) and relay compartment. So I had the car running and dissconnected the ECU one plug at a time and had no difference at all in the idle or the way the car ran.Then with the ECU unplugged I started the car and all was the same. I did expect to see some kind of difference but no.. Then with the ECU plugged back in and the car running I disconnected the RPM relay and the car stalled out. What is going on??? Is the ECU not sending a signal at all ( it sure seems like it) Anyone have this issue before.. Need help soo bad. This car needs help so bad..

[dmc6960]

I have been following this thread because we seem to have some what similar problems. I have bee playing with my idle and the one thing i have been checking is my ECU (behind driver seat) and relay compartment. So I had the car running and dissconnected the ECU one plug at a time and had no difference at all in the idle or the way the car ran.Then with the ECU unplugged I started the car and all was the same. I did expect to see some kind of difference but no.. Then with the ECU plugged back in and the car running I disconnected the RPM relay and the car stalled out. What is going on??? Is the ECU not sending a signal at all ( it sure seems like it) Anyone have this issue before.. Need help soo bad. This car needs help so bad..

Did you verify if the idle speed thermistor is connected properly. As earlier posts in this thread point, these recent posts have into on that...
http://dmctalk.org/showthread.php?241-What-have-you-done-to-your-DeLorean-today&p=100638&viewfull=1#post100638

Unplugging your RPM relay will always kill the engine, its the relay which powers your fuel pump, and has nothing to do with the idle system.

[Some guy]

Hey Krs09

That was the same thing that was happening to me. Here are some things test.
1 Make sure your ISM is good. Mine had 12 ohms from the center pin to the left and right pin. also disconnect it and make sure it moves freely. I even tested mine with a 12V source to make sure it moved.

If you think your ISM is good. Test the wires going to it. The center pink pin should have 12 DC, the green and red wire should have 100 Hz. The AC voltage on the pink and green wires, i had a hard time reading. They were near 0 V AC for me, but i read they might also be 12v AC.

If every thing is working properly, the ISM disconnect from the intake manifold should feel like a week cell phone vibrating in your hand. It should be like this with the key in the run position. The car doesn't have to be started.

[Bitsyncmaster]

Hey Krs09

That was the same thing that was happening to me. Here are some things test.
1 Make sure your ISM is good. Mine had 12 ohms from the center pin to the left and right pin. also disconnect it and make sure it moves freely. I even tested mine with a 12V source to make sure it moved.

If you think your ISM is good. Test the wires going to it. The center pink pin should have 12 DC, the green and red wire should have 100 Hz. The AC voltage on the pink and green wires, i had a hard time reading. They were near 0 V AC for me, but i read they might also be 12v AC.

If every thing is working properly, the ISM disconnect from the intake manifold should feel like a week cell phone vibrating in your hand. It should be like this with the key in the run position. The car doesn't have to be started.

You can also watch the valve move after turning on the key. It should open a little less than half way (temp dependent) and then take about 20 seconds to open fully (I think that is how it worked). It opens because the engine is not running so it increases the idle speed.

You will feel the most vibration when the ISM is half open. Fully open or fully closed will have little vibration.

[krs09]

You can also watch the valve move after turning on the key. It should open a little less than half way (temp dependent) and then take about 20 seconds to open fully (I think that is how it worked). It opens because the engine is not running so it increases the idle speed.

You will feel the most vibration when the ISM is half open. Fully open or fully closed will have little vibration.

I did do little checks on the ISM. It does have a buzzing feeling with the key on. When I looked into the valve after turning the key on I can see it go from fully open to about half open and wont move after that. It doenst move as freely as i would think, it does shutter a little when closing to that halfway mark. I reached in there with a little screwdriver to move the valve and I can close it if I try but as soon as I take pressure off the "door" it goes right back to about a 1/4 of the way open. When the car is running and I disconnect the ISM there is no change in idle, I would think something would change but no.. The buzzing stops but thats it. I will check ohms and volts over the weekend.. Well, try to. I'll have to post a pic of my fuse box compartment, its a disaster, after market wires and blue conncetions all over, inline fuse holders, both rear speaker are just not connected at all. --Heavy sigh-- :bawling:

[Bitsyncmaster]

Don't use a metal tool to move the valve. If you scrach the valve it may not work again.

Removing the power to the ISM will just keep it in position. If it buzzes then your ECU driver transistors are working.

[krs09]

Did you verify if the idle speed thermistor is connected properly. As earlier posts in this thread point, these recent posts have into on that...
http://dmctalk.org/showthread.php?241-What-have-you-done-to-your-DeLorean-today&p=100638&viewfull=1#post100638

Unplugging your RPM relay will always kill the engine, its the relay which powers your fuel pump, and has nothing to do with the idle system.

So today i get my hands on a jumper wire to give this jumping the thermister a shot and to my complete suprise the idle came down the it began to idle hunt for about 15 min and boy did it hunt. It did stall 3-4 times but restarted pretty easily. After a long time of hunting it seemed to settle and started to purr.. What a wonderful feeling.. I know im still far away but this hurdle got a little smaller. When i was getting ready to leave i disconnected the jumper and the idle stayed low until i turned it off..Weird. Im going to test it again on Mon. If I jump the thermister for good what the downfall? Will it hurt the car or its not really needed? Thank you so so much for the great tip.

Bonus: Heard my cooling fans from DPNW work for the first time! So quiet.:nana1:

[Elvis]

The thermistor only really has an effect at very low temperatures and increases idle.

The reason you want ot replace or fix it is because you want a fully complete and working car.
But yes, for the moment a bridge is OK.


BTW - I had a car last year that had the same problem with the temp sensor. The sensor was OK,
there was just a bad connection. cleaned it....

[Bitsyncmaster]

The thermistor only really has an effect at very low temperatures and increases idle.

The reason you want ot replace or fix it is because you want a fully complete and working car.
But yes, for the moment a bridge is OK.


BTW - I had a car last year that had the same problem with the temp sensor. The sensor was OK,
there was just a bad connection. cleaned it....

+1

Not sure with the OEM ECU but with my new one the thermister will also help with how the engine starts cold.

[krs09]

Damn.. So I was able to bridge the thermister wires at the ECU and car began to idle hunt, after a long while it seemed to settle... Fast forward 2 days and now I cant repeat the process. I try to bridge the wires again in the same order and the idle is very high like it was:angry:. I wanted to bridge the wires for good but when I tried I got the same high idle results. Only one time the car started to idle hunt but never settled down, when I turned it off then on again in a 2 min period the idle went back to around 2000/3000 rpms and would not hunt.. The only time the car even came close to settling is when it ran very rough, desprate I pulled the screw out of the AMU (adjustment screw) and she ran a lot smoother. I turned it off and restarted and it ran like shit. I really dont know what did differently. I know i had a good connection for the bridge. I know we have been over this again and again but ANY OTHER IDEAS? I just know im gonna have to pull the intake again:banghead:. This thing is killing me. Any good Delo techs in the phila area? Any tips or advise of any kind would be great. Why would it seemingly work and when its restarted all is lost? I still havent taken it for a good ride since i boughti it (Aug). The good news is she doesnt overheat (DMCNW fans work beautifully) and it does not leak. Two major reasons I pulled the engine in the first place

[Some guy]

I had a high idle when my red and green wires on top of the ICM were switched. when i switch them the idle went to normal. This was because the previous owner destroyed the plug and i had to go off of drawings to set them right.

Did you check if the distributor is getting vacuum advance when it should not be?

[krs09]

I had a high idle when my red and green wires on top of the ICM were switched. when i switch them the idle went to normal. This was because the previous owner destroyed the plug and i had to go off of drawings to set them right.

Did you check if the distributor is getting vacuum advance when it should not be?

It seems like it is (clicks when disengauging the idle micro) and the connection looks good. The ICM connections look really good and the plug and terminals look good. Now it almost sounds like I have a vac leak (loud whistling) under the AMU but not sure. Im thinking it may be the POA or the vac line that goes under the w-pipe. All the hoses are new and silicone though. :mad2: