Hi guys! (And girls) I'm Andrew For background: me and my brother have built a lot of vw's with no issues, but as soon as it's he gets a mk2 Jetta it nEver works again. This time we had a original 1.8 16v kr engine running ok, but rattling. So when cheap abf engine popped up it was brought, chipped ecu all the bits... great. Engine was fitted and engine harness plugged in, started up after abbot of earthing issues and ran mint. Then it's died WHILE RUNNING *in capitals because it's the theme here! So we hunt through every single sensor and found no issue, until we found the ecu relay 32 was missing? How was it running without it? Then we fitted the correct relay and still nothing. Tested a new ecu, bingo! Running, driving, went like stink! But then after a few days and the first night the battery was left overnight attached it started and cut out. Ecu again. No spark except when the ignition is first keyed on. Current situation: brand new crank position, air temp and lamba. If the ignition is turned on and the crank position is manually operated the fuel pump kicks in and injectors fire. On the 3rd ecu now. What causes recurring ecu failure? Do we bin the loom to rule it out? Does anyone have a pin out for the early ab ecu? Any help would be appreciated because I'm lost! P.s we have no vagcom it's in the post should arrive Monday!
the 16v doesnt use an ecu relay thats a digifant thing. top cause of ecu death for the 8v is poor gearbox earth. 16v doesnt usually suffer the same issues but well worth a check anyway. Later cars have the battery earth runnign to a stud on the end of the rear engien -> gearbox mounting bolt, make sure you have this setup. I would go for mk3 or new battery cables while you're there, the originals are probably past their best
Rubjonny- I've read so many of your posts about these engines cheers for the response. Your saying the 30 relay in position 3 isn't important on the abf engine? I'm going to in unwrap the lion tonight and check the earths to each item, I found the ecu pin out in your files that should help. BUT you mention battery cables? That's a huge floor on this car the battery is at the rear and the front to rear cable is not overly substantial I'd say 0guage of 25mm squared. Are the Ecu's very voltage sensitive? Will let you know how we get on. I'd say we need another ecu tho, the 3 we have just won't produce a spark.
ah I missed it was abf swapped with all the ecu etc sorry yes you need an ecu relay for that, the abf one is actually a #30 but a #32 will work just as well. if you suspect its faulty though get a new 30 relay from VW they are dirt cheap with the battery cabling if you suspect that might be poor try running a couple jump leads from the battery to the points in the bay to rule it out
After some checking. Found sensor earth back to ecu not in great condition and the intake air temp sensor (black wire) was live, at ecu where its blue yellow, must be that melting the ecu will unwrap loom and find short and we'll replace the air temp sensor too. Just waiting for new ecu.
