so i have a mk2 scirocco with a vr6 turbo in it. fuel pump primed properly when i parked it in december. i have a 167 relay in the original rocco (CE1?) fuse box and added ecu pin 6 (OBD2) into the back of the fuse box as per rubjonnys instruction and it worked perfectly. anyway. i haven't tried to start it since dec until the other day. no fuel prime and wouldn't start. will start and run if i jump the big pins where the relay goes. i have continuity between ecu pin 6 and the little relay pin 85 so my wiring is still ok. just not sure what to test next. or should i just get a new relay as its most likely failed even though its only 6 months old! i know pin 85 is an earth trigger so assume it would have continuity to earth when i turn ignition? so that mean pin 86 must be live. is it all the time, or on ignition, does the power come from the fuse as fuse no5 did not have 12v at it. any advice? thanks
i have feeling pin 86 is on a 15 so is only live when ign on and cranking. and the fudse feeds the positive on the big pins, i think i'm just going to get another relay and see if it fixes it! i am getting too confused
ok, now realise 15 is live with ign on even if cranking, makes sense, so pin 86 should have 12v to it with ign on. which it doesn't . hmm. what next?
i just tested the relay and it clicks when 85/86 connected to battery. but not when plugged into car, so it looks like the issue is 12v supply to pin 86 within the fusebox. any ideas?
quick n dirty test to see if the relay socket pins are ok is swap the 17/18 relay in slot 2 and fuel pump should always be on with the ignition. If it is that leaves relay fault or the ecu isnt triggering the relay for whatever reason. If the pump still does nothing with this relay fitted then this tells you the fusebox is faulty or a problem with the ignition supply, though if everything else works perfectly fine then it wont be ignition issue. Any signs of corrosion on the fusebox?
is that a relay with 17 or 18 written on it? that would make life easier. will try tonight. corrosion wise it looks fine as car is garaged. All the other ignition stuff works too. I was thinking that although the relay clicks when done on the battery, doesn't necessarily mean its working....
yep, its the X-contact relay you already have one on your fusebox just swap it over and see if the pump comes on with ignition
john, relay 17 tested and fuel pump runs on ignition. also although i can't hear the fuel pump relay click i can feel it which i didn't test before. so that tells me it the fuel pump relay as its being triggered, just isn't connecting and i know the other bits work due to 17 relay. your a genius mate. thanks again.
so i stuck a new relay in and nothing. any ideas? works on ignition with relay 17 in slot works if i bridge the two large spades i have continuity between ecu trigger and relay. how can i test ecu is sending trigger? or could it just be another duff relay?
i have just checked and relay wasn't clicking. it was the one below misleading me. so does that mean its not getting a signal from the ecu?
so the fuel pump definitly runs with the 17 relay fitted, but not when relay removed? If so you know the 67/80/167 fuel relay has all the feeds it needs, except the trigger signal from the ECU. However the late OBD2 ecu will not prime the pump on ignition, only when you're cranking it over. I assuemed you were trying to get it to fire and had no pump at all? Does engine start and run with 17 relay in? the ecu needs ignition live trigger top switch on, this may be fed from fuse 17 or 18 on the fusebox depending on how the loom was made. Check you havent got any spades fallen off the back from ECU loom that went to G spade 2 or 5 for your ignition live feed (1 and 3 are no good for ecu feeds as they go dead while cranking)
