Good morning and happy Tuesday to you all, I have just taken delivery of an L reg Mk3 with an ABF engine, the vision is to transplant it into my Mk2. In order to check the engine before I start to transplant it, I wanted to start it and ensure it runs. Fresh fuel, checked fuses, new battery. The car starts then cuts out pretty much straight away. It does this every time. Video at the bottom. I have checked to see if the (one) key I have has any kind of immobiliser transponder in it. It just has the battery and a bulb inside. I did a call to arms on my local FB page and a very nice chap came to my house and used two different diagnostic computers. We stayed a socially responsible distance apart. The VCDS laptop and the Snap-On box both had the same error, they couldn't communicate with the ECU. He said there was nothing more he could do from a diagnostic standpoint. I've removed the ECU and visually checked the board, there doesn't appear to any damage or shorting to the board. I've re-seated as many plugs and sensor connections as I can get my hands on but the same problem persists. Does anyone in the hive mind have a suggestion as to what direction to go, I won't accept "take it to the wreckers yard". Many thanks in advance.
L reg would be 93 so it shouldn't have an immobiliser, to double check get the ECU part number though as it could have been swapped. will it run if you hold the throttle open? if so might be the isv or wiring to it. if it wont fire with throttle then it could be crank sensor, have a good look at it if all cracked on the insulation or sensor on block just replace. if you can get a vagcom/vcds cable to connect you can check the ecu measuring blocks and scan all sensor inputs in real time, check engine rpm and it should go up while cranking. if not, crank sensor
with diagnostics you should have a grey/white wire from ecu loom to fusebox, on an early car it plugs to the diagnostics jumper block above the fusebox. then the vagcom port is wired to that, and gets live and earth from the ciggy lighter. if the fuse for the lighter is popped that could explain lack of diagnostics
Exactly right, the two letters that follow the number are AB. Thank you for taking the time to reply.
I'll check that this afternoon. As for the diagnostics, they're not even able to communicate with the ecu. Thank you for replying.
UPDATE: Starting with the throttle wide open caused a really rough idle with some kind of 'forward' fire back out the throttle body. I took in turns to disconnect each of the spark plugs and turn it over, same result. Feeling there may be some kind of fuelling issue, I decided to disconnect the distributor from the coil to draw some more fuel in. It turned over fine for a little while thinking it might draw in more in fuel. It fired and sounded normal for 3-5 seconds, then cut out. After a few more cycles of this, the engine managed to idle. Very lumpy, but an idle nevertheless. Progress is being made.
ok so thats a non-immo ecu all fine that side of things. sounds like you're getting there, with diagnostics see if you can find the grey/white wire from the ecu it should run to the diagnostics jumper block clipped to the top of the fusebox, then from there it runs to the 2x2 port behind one of the dash blanks. should have 12v across the power side of the plug also.
