Keeps dying

[poncho62]

Have a puzzling problem.....Every now and then, my 97 K1500 (350 engine) will just up and die on me....I then try and restart and I can crank, crank, crank and no start...Then a couple of minutes later it will start and run fine again. It first did this a couple of months ago. It has spark while it wont start, shot a bit of gas down the throttle body and it fired for a few seconds. Hooked up a pressure gauge and no fuel pressure....so one would think fuel pump, right?

Strange thing is.....it did this and then was OK for 2 months....It did it again the other day....quit on me about 5 times by the time I got it home. Called my friend who has a lift and took it over to his place, quit 2 more times on the way. He has had it running off and on for 2 days now, drove it all over and of course it wont quit again now. Starts and runs like normal....

We are thinking fuel pump still, but am wondering if it may be something else...maybe something in the wiring?......have changed the relay, didnt make any difference. I would think the fuel pump would either work or not......not be sparatic like this

Any thoughts on this?

 

[kennythewelder]

When I had my 93 WT it did the same thing. I dropped the tank, and it had about 1 quart of water in the tank. I dried it up and it never did it again. Also what does the filter look like, could it be plugging up on you? This would explain the no fuel pressure, where the water wouldn't. If you are putting fuel in the throttle body and it starts, then it is starving for fuel, no doubt. It could be a short in the wiring, or the pump itself also. I know that when I had issues with my 97, it made all the difference in the world when I changed out the pump with a good quality pump. These engines 1996 up are very sensitive to fuel pressure. The fuel pumps on these trucks do get week and don't put out the pressure that they need to, (60 plus PSI on start up) and the truck will still run, but will be hard to start after it sits for a day or more, and it will have a loss of power at WOT above about 3200 RPM, or that what mine did anyway. When I did my 93, I got the water out of the tank, (after I dropped the tank) with a wire hanger and several rags to mop it up. It worked good for me anyway.

 

[poncho62]

Thanks Kenny.....The fuel filter was changed in the fall, so should be good......

I put a fuel pressure gauge on it the other day.....60+ on start up.....running it is consistently at 53 lbs

We are probably going to throw a new pump on it, but will be POd if it keeps doing this even with a new pump.....lol

 

[glfirefighter144]

My 98 did similar, usually wouldn't start in the morning, but give it some ether or even hooking jumper cables would start it, fuel pump fixed all problems, no issues since, low quality fuel could clog filter, never hurt to change it again, most pumps only warranty with new filter anyways, hope you get it sorted out

EDIT: also check all grounds and connections are tight and clean

Sent from my DROID RAZR M using Tapatalk 2

 

[1996*GMC*SHORTBED]

Did you know about the GM Technical Service Bulletin, with regards to all our year trucks? It is about the great wiring pigtail harness that plugs into the top of our fuel pumps, that GM used. They short out & burn. Inexperienced mechanics replace fuel pump after fuel pump after fuel pump & can't figure out the problem. They replace the fuel pump relays, in the power center, under the hood. They can't figure out whats going on? This is why all new good replacement in-tank electric fuel pumps come with a new pigtail wire harness these days. GM did'nt issue the Service Bulletin for years after the fact.

 

[kennythewelder]

Did you know about the GM Technical Service Bulletin, with regards to all our year trucks? It is about the great wiring pigtail harness that plugs into the top of our fuel pumps, that GM used. They short out & burn. Inexperienced mechanics replace fuel pump after fuel pump after fuel pump & can't figure out the problem. They replace the fuel pump relays, in the power center, under the hood. They can't figure out whats going on? This is why all new good replacement in-tank electric fuel pumps come with a new pigtail wire harness these days. GM did'nt issue the Service Bulletin for years after the fact.

Your fuel pressure sounds good Poncho62. It is normal for the pressure to fall to the 50s after start up. I want to say my pressure is 62 or 63 at start up and 53 or 54 at idle with the new pimp. Like 1996*GMC*SHORTBED said it may be in the wires at the pump. LOL I guess if you change the pump and it has new wires, and that is the issue, than that will fix the problem. Send us a post and let us know what you find.

 

[poncho62]

My mechanic friend told me about replacing the wiring harness if we put a new pump on....Its just strange that its good fora while then suddenly acts up, then is back to good again....Going to check the grounds this weekend

 

[1996*GMC*SHORTBED]

Any update?