I just bought a '97 SLS wil 89k miles knowing the fuel pump needed replacement. The car was hard starting (cranking for 10 to 20 seconds to start when it was cold). I changed the pump today and everything was peachy and I had so much power I nearly wet myself. Parked it in the garage a few hours later and now it doesn't start. I can't hear the fuel pump even charge up. When I was shopping for a pump I noticed that there is a new wiring harness that is 'recommended' by a manufacturer that should replace the stock harness because of significant power demands of the fuel pump. Does anyone think that this wiring harness could be the problem or might it be more severe such as a bad fuel pressure sensor? I tried to jiggle the connector to the pump but it didn't do any good. I have also checked the fuse and the relay but with no luck. I even went so far as to ohm out thethe fuel pump from the relay itself and there is still a good connection.For it to just stop workingafter running flawlesslyis currently beyond me. I REALLY don't want to drain all of my gas again. Also, my dash comes up with 'Service Fuel System' but there is no trouble code in the computer, so I have no idea what it wants me to service. Help... anyone?? Bueller? Bueller?

 

I should also ask: There were three lines on the fuel pump, main fuel line, return line, and canister line. Does anyone know the order of the return and canister lines? And supposing they were erroneously placed would it lead to this current problem. Thanks.

 

If fuel line are crossed car would not start. Since you were able to start car, they should be ok. "SERVICE FUEL SYSTEM" message should have code tied to it. If you still have old pump assembly do any of the terminals appear corroded or burnt? Check jumper harness to sender for the same. It can be removed with out dropping tank completely out of car. Does fuel gauge work?

 

Yes, the fuel gauge does work now with the new pump assembly installed. I also checked the old pump and the termialslook normal. There isn't any melting or charring or even anything that resemblings arcing.
Today I had been taking the fuses and relays out to clean the terminals because some of them were corroded (which leads me to think the car was in water). Anyhow, I put them back in and turned the ignition on and the pump whirred itself to life. I thought that maybe I had found the issue, so in my haste I turned off the ignition and opened the garage door. When I returned to turn it on again, the pump didn't do anything. I returned to the hood and while I was looking at it, I heard a relay click off. I'm not sure which is was, though. I went to the ignition again and turned it on and the pump started again and so did the car. Whether or not the relay I heard and the fuel system are related is yet unknown. After doing some more investigation, I found out that the camshaft position sensor tells the PCM to turn on the pump, but that the oil pressure switch can turn it off again should the pressure get too low. This tells me that the pump itself is probably good (because it appears to run fine when told to do so), but it's more likely to be one of the sensors up in the engine compartment.What are your thoughts now?

 

Recheck for codes and post even if not P code. Check grounds. There are several on engine, transmission, core support, and in trunk behind trim / liner.