blue temp sender is the one on the flange for the top rad pipe... also check the cam belt sprocket on the end of the crank shaft.... the centre bolt on mine had worked loose and the key in the back of it had sheared out of it... so the crank was spinning out of sync with the cam and the timing Paul
if the blue temp sensor change doesnt help then try the Ignition moduel that sits ontop of the ecu. Happend to me a few times. It also flooded my engine really badly. I disconnected the coil, removed the spark plugs. cranked the engine over and the remaining fuel spat out the spark plug holes. Then i managed to start it. Digis are very delecate
Just been out to the car again this morning. Been having another look at the wiring, found the ISV relay (number 43 position 16) had some bad corrosion on a couple of the tracks, changed that, but still nothing. It still seems to be flooding as soon as you try to start it! I've listened to the fuel rail as it's trying to start as I can hear the injectors clicking open and shut, but it still seems to be chucking in too much fuel. Tried disconnecting the Full Throttle switch to see if that was faulty, but still nothing. How would the Temp sensor effect the start-up, surely it would fail in a position where the car is trying to start from cold and so would only effect the car once its running?? Any help still gratefully received!! Cheers
relay 43 is for the coolent level sensor warning light, not ISV. The ecu controls the isv direct ecu temp sender can and does fail in such a way the car cannot start, I have had this a few times myself
In the haynes manual (I know they're not right all the time) it says that relay in position 16 is for the idle speed control, in my car that is a relay with the number 43 on the top?!?! Are there any test that can be done on the temp sensor before getting a new one? Just I don't have another car at the moment so can't just drive to the local VW stealers! Cheers
yeah unfortunatly this is one of those times when the haynes is wrong that relay is only there for k-jet models, have a look at my fusebox FAQ, it explains what each relay does you can test the resistance but even this doesnt help as it could be within spec but still be a bit broken and fail intermittantly, its only 13 for a new one but if you have no car that makes things tricky, gsf ones arn't very good either!
Well its a good job that I don't believe everything in the ol' Haynes manual!! Do you know where I can get a decent wiring diagram (that's correct) for the ECU, ignition and Injection circuits?? I'll have to see if I can get someone to give me a lift to a stealers for the temp sensor. Really am getting fed up with this fault thing now! Would be good to be able to drive the car again.... Cheers for all your help so far!!
the haynes does have diagrams for the digifant engine, complete too! Last 2 in the wiring diagram section. However since its a CE1 engine (or at least I assume so as it has that #43 relay above the fusebox, as 90spec CE2 didnt have it) then they arn't ideal as they're CE2 If you PM me your address I have a CE1 jetta diagram which includes the digifant engine, plus has complete internal fusebox circuit traces so its very handy!
It's the PB engine I have (one of the early Digifant engines as it's a 87-88 car). I've just been out to the car and jotted down all the relays and their positions, they are as follows: Position Relay Number 1 53 2 80 6 53 8 17 10 19 11 72 12 21 16 43 17 10A fuse?? I've looked on the FAQ on fuse boards and notice that position 1 is for the ECU on early cars, so I tried swapping the two 53 relays over, but still nothing.... and the horn worked with both relays so I guess the two 53 relays are all good. Would a faulty fuel pressure regulator cause the engine to over-fuel and not start?? Just thinking around everything to try to come up with a solution!! Cheers
right, relay in slot 1 should be a digi ecu relay which has a different pinout to a horn relay, so that'll be why it doesnt work I'd guess. The rest all look fine! You need a 32 relay for that slot, others have said later ECU relay from a MK3 will work too, and they all have ECUs so shouldnt be hard to track down! The fuse is probably for your foglights Its possible the fpr could be the problem I guess, but the less vacuum there iks the more fuel it dumps, make sure the vacuum lead to it is connected up though they usually still run without it but badly! Oh and sionce its an early digi the ecu temp sensor might not be blue it may be white, threaded into a metal flange on the front.
Woul dchanging the ECU for a different suffixed one (E for a AN) mean that I shoudl change the relay too? I've never touched the relays before and the old ECU alway worked (right up until the point that it stopped!!!) Unless the relay fairies have been past, I've always had a 53 in position 1??!?!?! Really confused now!! I'll try to get a 32 from somewhere and a new temp sensor (it is a white one - I looked last night). I won't do any (more) damage plugging a 32 into position 1 will I?? Does the voltage across the injector lead with the ignition on mean anything (se previous post #20)? Sorry- so many questions!! Thanks for the wiring diagram, I'll have a look at it this evening as I can't get to my emails at work (page blocked) Cheers
nah all ecus are interchangable, just make sure it has 'digifant II' on it! The injectors should get a constant 12v, and are earthed by the ECU. If you get 12v across the pins with ign on but engine off, you have a blown ECU or the earth wire is shorted or incorrectly wired to ground somewhere along the way. The ECUs blow if the gearbox earth is poor, so check this out. On later MK2s there is a stud on the rear gearbox -> engine mounting bolt fit one of these from a late MK2 or MK3 and wire this direct to batty -ve with chunky battery cable.
