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1997 Grand Prix GT fuel pump help needed

K

kaylas97gp

New member
My girlfriend has a 97 Grand Prix GT with the 3.8 non-supercharged. Auto trans. The other day, she was running it to warm it up before going to work and out of nowhere, it just died. I went to work on it, it does have spark and air. What it's missing is fuel. The fuel rail is bone dry. I did the usual; checked all fuses related to the fuel pump and all were OK. Put in a fuel pump relay and that didn't cure it.

Today I did some more work on it and am really confused as to what is going on. When the key is turned on, the relay energizes for a few seconds as it should, and shuts off. While cranking, the relay is energized. But I get nothing at the fuel pump itself voltage wise. I hooked up my Snap-On scanner and used it to command the relay on, and still nothing at the pump. I admit I need to double check that my scanner is actually turning the relay on when I tell it to.

I'm thinking the obvious answer here is the power wire (grey I think it is) that supplies power to the pump has an open in it. I'm not sure where exactly that would be which is why I'm here. I admit I'm spoiled and have the factory service manuals for all my vehicles but she doesn't have one for hers; all we have is a poopy Haynes book. Also of note here is that the car has a few trouble codes; misfires and a transmission component slipping code I haven't gotten to yet. It does have a crankshaft position sensor code but the number escapes me at the moment...plus I have spark so I don't think that's it but figured I'd throw it out there in case it does.

Can anyone tell me where GM ran the wiring for the fuel pump back to the pump so I know where to look? Also is this a common problem on these cars and is there a common area where a break may have occurred? I know it doesn't have that fuel pump resistor because it isn't supercharged. Thanks!
 


well just for kick, take a big rubber mallet and have her start cranking it over and you smack the bottom of the fuel tank, see if it turns back on.
 


i agree that the pump may be going out. what the problem is power isn't getting TO the pump. i disconnected the connector at it and tried every possible combination of relays, scan tool, jumping the relay terminals i could think of to get power back there, and there is none. the sending unit still works as if connected it shows half a tank and if unplugged it shows full. but there is NO voltage getting TO the pump. once i can figure that out i can go further in diagnosing the pump.
 
Ignore the speed relay and resistor since you don't have the SC motor. All else is the same.
99FuelPump.gif


99FuelPump2.gif
 
thanks for posting that diagram. so then, am i correct to think that the PCM controls the fuel pump relay, and the grey wire runs from the relay to the fuel pump on a NA 3.8? If I don't get any voltage on that wire, as long as the feed side of the relay has power to go to the pump (but isn't probably due to a broken wire), then I'll probably end up just running a new wire back to the pump in place of the grey one, since it vanishes into the main harness and I don't have time to find the break.
 


I took the pump out and hooked it directly to the battery it just makes a click sound .. Pump is bad .. That's just my luck .
 
I have a gas tank and pump from a 2007 model , I'm thinking highly about trying to get that under it . Funds are low right now so I have to try anything at this point . I also should have listened to the guys that were telling me the trans from the 07 would not work in the 97 , however my brother in law is a mechanic and said oh it'll work , everything's the same . Last time I listen to him again !
 
The '07 is a returnless style system, that pump won't work. You can give it a shot, though, best way to learn is do it and see why for yourself, just like with the trans. Cheapest option would be either junkyard, or get a replacement pump for $50ish off ebay and pull the canister apart. Whole delphi unit runs about $180 shipped on amazon.
 
Trying to just sell this stupid thing .. I am kicking myself in the rear for ever trading my jeep for these cars .
 


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