MK3 Golf GTI 16V Stalling below 1200rmp.......

[Leon27]

easily done.   

worth checking the cam/crank sensor is attached and working else no sparks will be triggered.

Good advice, think a second problem has possibly arisen. Check all your fuses and get it scanned again?

[Dogbot]

Whoever mentioned fuse 15, I f*cking love you   
Just sorted this idling problem thanks to you, it's been the bane of my life!

Aww do stop your make me blush! Pmsl, to the op, sorry. Yours is still a no go, a reading of 0 at the plug an a fresh fuse would suggest a wiring problem trace them back to the multiplug connector (round one) and just age to check them and the terminal connections too
Sorry I can't be of much more help

[DanChave]

Cheers everyone for all the info and advise so far

The two wires from the ISV plug are white and black, the black wire goes right round the back of the head to the TPS, the white goes into the multi plug. I checked the multi plug and the pin corresponding to the ISV and got no reading (I'm guessing I would be looking for slightly higher then at the ISV plug?) Tomorrow I will get off the loom tape on the loom going along the right chassis leg and see if I can spot the route of the cause. Most of the loom looks to have been re wrapped in electrical tape, I had planned on re wrapping everything in proper loom tape, but not until I had relocated a few things.

[DanChave]

Soo.... Today I got all the electrical tape off the loom and traced the white wire from the ISV pin in the multi plug, all the way back to the ECU. I then tested the circuit from the ECU plug to the ISV pin to see if there was a break in the wire and it read fine! I did this for the crank sensor as well because I knew everything was fine with that. I then reconnected the battery and the ECU and checked the voltages at the Crank Sensor Plug and ISV Pin in the Multi Plug, again, the crank sensor read 10v and the ISV read nothing. I'm now thinking the ECU may be faulty? I opened it up and everything looked absolutely mint........... Should I send off the ECU to get checked or just but a second hand one??

[Jeanene]

 I'd say try that as first bet, then take things on from there

[Dogbot]

Ecu's rarely go wrong!! An usually when diagnosed incorectly as faulty it's because the garage can't find anything else wrong, I honestly sincerely doubt your ecu is at fault, thee has to be something else amiss

[Leon27]

As Dogbot says, an ECU rarely goes down unless water or a hammer gets to it but you never know. I'd verify this:



If you can't zoom in then this is what you can try:

You have measured the resistance from Pin 27 of the 68 pin plug to the ECU to Pin 3 of the ISV (the white wire) - 0.3 ohms and below is good.

Now the bit I'm unsure about is G6 where is called a "positive connection (15) in Digifant Wiring harness" - This is basically the Fuse 15 mentioned earlier so Pin 1 of the ISV should have 12v with ignition on.

Check that Fuse 15 is actually getting power on both sides
Pull back the wiring loom on the ISV plug and make sure the pin/wiring isn't damaged
Try to trace this wire back as best you can round the back of the head....

Now this is the bit which might be tricky to see, these wires round the back of the head bake and get sh!tty. Visually they look ok, only when you pull back the insulation and you see the wires burnt.

I think the voltage from Fuse 15 gets split to the crank case heater plug (the redundant plug that plugs into the crank breather pipe) you should have 12v there and at the ISV if the wiring is good.

The ECU doesn't provide the +ve, it looks like it's an earth switched system so the ECU is hopefully ok so definately check the wiring round the back of the head

[DanChave]

Cheers for all the help guys, I'll get right on this tomorrow off the top of my head, there was no reading at the crank case heater plug either and I have already repaired one section of loom that goes round the back of the head so I'll take another look.