its a 97 chev 2500 4.3. crapped out on me at the gnf a few years ago. had it towed to an atlanta shop where they replaced the fuel pump and mass af sensor. started great, but as i was pulling out of the shop it quit. the fuel pump wasent working again, so they pulled it back in and found that the harness connector to the fuel pump had deformed(overheated?). they installed a jumper from one side of the harness to the other and i was on my way, which makes me think that the connector have been problem the whole time. since then ive replaced the fuel pump again(2 years ago?) and its having the same symtoms again, fuel pump intermittently cuts out. banging the tank with a rubber mallet doesnt seem to help although it has worked after trying that maybe once. i think its soemthing other than the fuel pump as its only been about 30k since the first replacement. so it could be something to do with the connector again but why would it be deformed in the first place? should i ditch the submerged fuel pump a fit some sort of inline pump? this is my bike hauler and still runs great and gets 18 miles per gallon and the most important part is its paid for. Any help would be great.
Maybe check to see the voltage that is going thru that connector and into the pump.. sounds like it may be too much voltage and its frying the pump. May be a inline resistor/relay or something that has gone bad causing too much voltage to go to the pump ????
i worked my way through college as an auto mechanic so it's been a while, but a couple of things come to mind. 1. fitting an inline pump would be difficult (i've never done it), because i'm pretty sure the fuel pump is integrated with the fuel level sending unit and shares the connector. also, on FI vehicles the fuel system is under pressure, so you need hoses and special fittings that will deal with the pressure. in other words, regular hose and hose clamps won't work (not for long, at least). 2. is the replacement pump an OEM unit? i've seen aftermarket replacements go bad quite a few times. some of the aftermarket units i've seen require that you strip the ends of the wires, wrap them around and then screw down (kind of like a light switch at home). the connections also weren't insulated. for submerged fuel pumps i was never comfortable using one of these. 3. if the connector is bad, you could always get a new connector and solder it in. i forget where it is but there is a place online that you can match OEM connectors. 4. look in a chilton manual or something like that and check the voltage going to the pump. if it's an intermittent problem you may not diagnose the problem here, so check, or have somebody check, for a possible short. as a last resort, if it is a voltage issue and you don't have a short in the system, it could be your computer. as i said, it's been a while since i've done any real work on anything other than a bike, so somebody else may have some other ideas.
Or maybe some type of obstruction in the intake line, causing the pump to do more work than it should and wear out????? Good luck
It's the connector, with most Chevy fuel pumps you need to replace the connector. It usually comes with the fuel pump. Or get the the replacement pig tail from the auto parts store. Hope this helps.
i should have added - ALWAYS start with the basic things first. in this case, then you can get into the harder stuff.
Are you sure it's the fuel pump that's intemittently cutting out? My friend and myself both have 97 S-10s with the 4.3L. Both of us had trouble, both of us more than once with the trucks cutting out. Sometimes while driving (can feel a quick loss of power than comes back immediately) but sometimes when sitting and that sucks becuase then you're stuck. Between us it has been a relay, the ECU, the plug leads.
wow. i had the same problem before, had to replace the computer. this one when it happens you cant here the fuel pump when you turn the key on. and which relay went bad?
the 90's chevy truck fuel pumps are notoriously garbage, and the harnesses regularly crap out too. Even the best OEM pumps usually die around 125k miles. Some don't make it half-way there. Aftermarket fuel pumps sometimes literally only last a day or a week also. I dont know what pump you put in there when it was replaced, but the way to go is AC DELCO. since the pump doesnt spin up when the key is turned to ON, its not getting power so check the relays and fuses first. If none of the easy stuff fixes it, follow the wires back looking for shorts. If you are getting low fuel pressure at the test port, or zero, and the fuses/relay are good, the pump is prob dead. After that and no luck, pull the tank and check the pump itself. It may be dead. Replace the harness and pump with AC DELCO... dont forget to replace the fuel filter too, you never know if it is fubar'd and full of crap.
Remove the ground wire from the frame and clean it with sandpaper, the wire comes off of the tank sending unit. Clean the contact point on the frame as well. There is a fuel pump relay on the firewall, it can cause a long crank time, but does not usually stop the pump because the oil pressure unit overides the relay when pressure is acheived.
The connector is disfigured because of heat, yes, but... the load was way to much for the circuit ! Hence the first bad pump, or bad ground. It is only a 12 volt system, although I have seen voltage regulators stick and produce as much as 21 volts. That will pop the fuseable link from the alt. to the body and starter.
There is a tan W/ white stripe wire coming off the relay, connect it to 12 volts, pump should run, if not remove the pump, re jump wire and check voltage at pump. "DO NOT" I mean "DO NOT" , try to run the pump outside of the tank, it is a BOMB !!!
Not 100% sure. It was on the firewall, I wanna say like opposite the glove box? I think there were 3 of them there that looked very much alike all right next to each other if I remember right, and it was one of them.
Team is Right Yes your right. I have owned a repair shop for over 15 yrs. Many fuel pumps (GM) come w/ the new connector. If they bought a cheap after market, It may not come with it. This is why so many times i buy OEM. The fit, the parts, are just perfect. Team is right in what he said.
