Well the fun had to end somehow...
Car in question. Mk3 Golf GTI with 20vt AGU lump on standard management.
Picked up car from bodyshop on Wed 21st. Drove there no probs. On way home, sudden and severe missfire/no power. Stuck on scanner. Faults 01259, Fuel pump relay short to positive intermittent J17. I know relays are common on the mk3 so ordered one up. Before had chance to fit. Car stalls and dies afew times on the road. Park it up, wont restart. Replaced relay, still no joy.
Scanner now wont speak to car at all. What iv done.
Checked usual things, car has spark/compression etc etc...
Found Intermittent fueling, so checked relay. Found that the relay is arming/disarming itself randomly + intermittently, you can even see it arcing. So checked power at fuseboard for fuelpump relay. The pin that energizes the relay coil, i think its 2/86 is receiving a fluctuating voltage. Anything from 4v to 0v. Again, intermittent. 4/87 continuity checks to ground and other 6/30 + 3/85 had 12v iirc. Checked power coming through fusebox to pin G1/3 and found 12v there.
Checked the mk4 ECU, bared the wire at pin 4 the wire for fuel pump relay. The purple/white one, found constant 4v there. Is that enough?
Checked fuel pump, the two thicker wires. Found no power to the pump. But again must be intermittent because it has started since, but dies after 1/2 secs.
Only other thing iv noticed is the throttle butterfly actuator does what it wants as well with ign on, i know its supposed to open itself with ign on, but its just going on and off all the time, dont know if this is related. That and it will no longer speak to the snap-on verdict/sollus machines when before had no issue.
Any input is appreciated, im suspecting an ECU tbh... But anything iv missed?
