I have a 98 GMC Sonoma 2.2L that seems to start only when it wants to for no particular reason. It was in a flood about 2 years ago, up to the headlights. No problems until now. Half the time, the fuel pump will audibly kick on with ignition, the other half, it won't. Obviously doesn't start without fuel. BUT. If the pump won't start, all I have to do is jump it to another vehicle or put it on a starter and the pump starts EVERY TIME. Otherwise, there is no factor that will change when it starts or not; cold nor hot engine, cold nor warm weather. I have checked most connections from the battery to grounds, and to the starter, etc. As well as chassis grounds to electrical componenets such as the pump. Recently haven't tried anything else because it ran fine with no problems for three days, until today. Please HELP.
Check the relay and it's contacts, they might be coroded.
February, 8, 2006 AT 5:40 PM
That was the first thing I checked. We took the bed off to look at the fuel pump, checked that the pump itself worked, and continuity from the relay center to the pump-all good. We also checked the relay and coil itself, even switched it with the smae number from neighbor relays. Anything else you can think of? I've now stumped the mechanic from my neighborhood Autozone, from AAMCO, and my friend's dad - A master mechanic for Ford, Chrysler, and Chevrolet. Please reply.