I replaced the fuel pump relay on my Golf 2 due to not starting, car ran for a day, but the next morning same problem, fuel pump not starting (no noise on key turn as before). So I kicked the relay panel and it worked again. Ahaa, stripped down the relay panel but looks like new, so cleaned up all the cables for the hell of it, plugged everything back in, car still doesnt start, still no noise from fuel pump as before. :( What now? TIA
It would help if you provided more specific information on your car. Different fuel injection systems controlled the relay differently, but fundamentally, the following can be to blame:
ignition switch, relay, fuse, wiring, fuel pump, controller
In the case of CIS-E w/ Knock Sensing, the controller is the "knock box", if its straight CIS or CIS-E its probably the ignition coil. If its Digifant or CIS-E Motronic its probably in primary control unit.
It sounds like a loose connection in the relay box or a potentially faulty ignition switch. I'd turn the ignition on and if you don't hear the pump come on, start jiggling everything. It doesn't sound like the fuse, but if the fuse blows and you have a 3-wire oxygen sensor the heater is wired in parallel to the fuel pump so it may be a short in the oxygen sensor. I doubt its the controller or the pump either, but you might try pulling the relay and putting in a jumper and seeing what happens what happens. If you dont hear the main pump come on have someone tap on it with a mallet.
dan
fundamentally,
thanks, it's a Digifant system, the problem had been solved once or twice by kicking the relay/fuse panel, but all the connections are clean and tight, all except one tarnished main positive wire that I cleaned with grit paper back top the copper.
I already tried the jumper trick, a brand new relay, hitting the fuel pump, I'll have a look at the ignition switch later, I did also bash that a few times, but was really wondering if the panel or wiring loom have any known weak spots, I thought about a hair line crack in the brass rails inside the relay panel? I'm tempted to go out and buy a new one, but I never have any luck solving problems that way, always end up with duplicate good parts, as per the relay.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.