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?

mistaake

Things I can think of off the top of my head... fuel pump, fuel filter, fuel pressure regulator, fuel injector spider assembly, ECU/ECM/PCM/whatever you call it?

And I'm assuming you mean the 350 V8? Not aware of a 250

poncho62

Yes...350....thanks

Fuel filter was changed in the fall......no codes, so I would think computer is OK.....

Puzzling thing is, all is fine for months then all of a sudden it dies a few times, then is OK again.....frustrating

mistaake

Fuel pump issues probably won't set codes. So... I guess it kinda points to that? Does your fuel pump whine loudly? Was it ever replaced, and if so do you know with what type? Most cheap or even not-that-cheap aftermarket ones won't last nearly as long as the original OEM units for some reason.

tech2

fuel pump won't set codes but the fuel trim will be adding fuel...so do a hard accell and watch the fuel trim. If the fuel pressure is under 40psi the poppet injectors won't open at all.


I have a labscope so it allows me to view the current draw of the fuel pump and the waveform of the motor; helpful info which can be useful for hard to diag problems.

poncho62

As far as I know, the pump has never been changed. I cant even hear the pump run when its working good, but I am hard of hearing. The other day when it wouldnt start, I tapped the tank around a bit, but taht didnt start pump either....then all of a sudden after a few minutes, it goes and it starts.