Why is this issue not stickied??
I thought it was just my car, but it turns out it happens to several m42s.
Symptoms:
-Car starts fine when stone cold
-engine runs fine
-shut off engine to get gas/eat at a restaurant, run into a store,
-Go back to warm engine and start it
-engine starts and idles fine, but on take off engine stutters and will not rev with gas pedal depressed
-sometimes the check engine light comes on for a second
-Get the revs up above 3000 and it will run fine
-check engine light goes out, stomp test reveals 1444 - no issue code.
-runs fine for the rest of the trip after initial stutter/stalling issues.
- has same issue on next hot start
I replaced my car's vacuum lines assuming that was the problem at the same time that I replaced the coolant water pipe under the intake manifold. The first start worked great and i assumed i fixed it until I started it under hot conditions and noticed the issue was back.
I thought maybe the ICV was the issue and cleaned it to no avail. Then I noticed the issue was only happening on startup and I suspected it had to do with the open loop/closed loop transition in the ECU. I also thought my aftermarket EPROM chip may have been causing the issue but didn't have a spare on hand to test. I thought about replacing the oxygen sensor, cleaning the AFM, and rechecking for vacuum leaks but decided to do another search online.
Lucky for me, I found this thread on the m42club forums: http://www.m42club.com/forum/index.php?topic=7757.30
From that thread is this link to the wiring diagram clearly showing the wire should not be connected on US Spec cars...
I went out to check and sure enough on mine that wire is connected. I disconnected it and did about 7 hot starts and it seems to have fixed the issue. Here is a picture from that thread.
Why isn't this a sticky? It is very easy to connect the two on accident if you are under the hood and see it is disconnected.
I thought it was just my car, but it turns out it happens to several m42s.
Symptoms:
-Car starts fine when stone cold
-engine runs fine
-shut off engine to get gas/eat at a restaurant, run into a store,
-Go back to warm engine and start it
-engine starts and idles fine, but on take off engine stutters and will not rev with gas pedal depressed
-sometimes the check engine light comes on for a second
-Get the revs up above 3000 and it will run fine
-check engine light goes out, stomp test reveals 1444 - no issue code.
-runs fine for the rest of the trip after initial stutter/stalling issues.
- has same issue on next hot start
I replaced my car's vacuum lines assuming that was the problem at the same time that I replaced the coolant water pipe under the intake manifold. The first start worked great and i assumed i fixed it until I started it under hot conditions and noticed the issue was back.
I thought maybe the ICV was the issue and cleaned it to no avail. Then I noticed the issue was only happening on startup and I suspected it had to do with the open loop/closed loop transition in the ECU. I also thought my aftermarket EPROM chip may have been causing the issue but didn't have a spare on hand to test. I thought about replacing the oxygen sensor, cleaning the AFM, and rechecking for vacuum leaks but decided to do another search online.
Lucky for me, I found this thread on the m42club forums: http://www.m42club.com/forum/index.php?topic=7757.30
My vehicle is a non-cat version and when the receptacle is disconnected the idle goes to crap. When I set the scanner up for the "cat version" and look at the engine data, reference voltage for the O2 sensor is present.
It appears to me the ECU is set up for both cat and non-cat applications and the connector is sort of a "switch" if you will.
EDIT: The eprom is actually the "switch" so to speak. US Spec #1.267.356.378; Euro-spec #1.267.356.214
-If connected the DME looks for an input signal from the Idle Speed CO Pontentiometer, but it must have the Euro-spec eprom #214.
-If disconnected the DME looks for input signal from the Oxygen Sensor, but that is for US spec eprom #378.
The DME (aka ECU) part number on the case is the same for both US and Euro markets (0261200175).
Wish I could find something in the wiring manual, but there's nothing that jumps out at me and I'm not all that good with schematics anyway:o
It appears to me the ECU is set up for both cat and non-cat applications and the connector is sort of a "switch" if you will.
EDIT: The eprom is actually the "switch" so to speak. US Spec #1.267.356.378; Euro-spec #1.267.356.214
-If connected the DME looks for an input signal from the Idle Speed CO Pontentiometer, but it must have the Euro-spec eprom #214.
-If disconnected the DME looks for input signal from the Oxygen Sensor, but that is for US spec eprom #378.
The DME (aka ECU) part number on the case is the same for both US and Euro markets (0261200175).
Wish I could find something in the wiring manual, but there's nothing that jumps out at me and I'm not all that good with schematics anyway:o
I went out to check and sure enough on mine that wire is connected. I disconnected it and did about 7 hot starts and it seems to have fixed the issue. Here is a picture from that thread.
Why isn't this a sticky? It is very easy to connect the two on accident if you are under the hood and see it is disconnected.
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