Truck won't start....

[logikfive]

Truck is a '98 K1500 with the 5.7L.

When I got the truck I couldn't get it to start either, it would crank over all day long but not even a hint of combustion. I thought for some reason it was a bad connection at the battery. I eventually got it to run after about 20 minutes worth of messing with the battery terminals and nothing else. Shut the truck off, restarted it several times no issues.

Yesterday it did the same thing, it could crank until the battery is dead (which is a very long time considering I put an Optima Red Top in it) I played with the battery terminals again, this time however I could not get it to run. I then decided to pour a little fuel down into the throttlebody. She fired right up, ran a little rough for a second or two and cleared up. Shut the truck off and restarted 3 or 4 times again and it never gave an issue. Let it sit overnight, it wouldn't start again. Pour some fuel down in it and she fires right up again.

I haven't checked the fuel pressure yet, but I'm leaning to possibly a bad fuel pump. However, the pump doesn't sound abnormal. Just the typical whirring noise. I have tried cycling the key 5-6 times to get some fuel pressure before trying to start the truck, however it makes no difference. It still would not start.

It could use a set of plugs, cap and rotor look acceptable. I also know that it will not rev past 3,000-4,000RPM in park or neutral (Cannot put it in gear and drive it because it needs an axle) which also leads me to it being a fuel starvation problem.

Previous owner said they put a new fuel tank in it, but who knows if they replaced the fuel pump.

Does anyone have any other suggestions?

 

[Z Fury]

Fuel pump or fuel filter is my guess. I do agree that it sounds like a fuel starvation issue.

 

[TruckinAin4Sissies]

I'm 99.9% sure its the fuel pump. Always replace the filter afterwards.
Get the whole assembly, not just a pump (If you can afford to), if not be sure to get a new pick-up screen (looks like a sock).

 

[logikfive]

I finally picked up a fuel pressure gauge, and at the rail at the schroeder valve, I only see 48psi when I prime the pump to start the truck and I can watch it bleed down if leave the key off. I can cycle the key several times and the pressure never goes above 48psi. Since I'm at the rail itself, that rules out the fuel regulator, correct?

I priced out a fuel pump and $260 makes me want to be certain that the pump is the problem.

Thanks
Joe

 

[TruckinAin4Sissies]

AutoZone:
Replacement pump $80
Whole assembly $230

You must be registered for see images attach

 

[logikfive]

Yeah, I priced it out through Rockauto after getting the part # from Advance for it. Same pump from Advance is $260, and it's $150 from Rockauto. I'll definitely be going that route.

Would you still agree it's a fuel pump issue?

Also, Advance gave me a different model and said there was a difference in wiring, some are two wire and some are single wire? Not really sure what he meant but the # of the pump they gave me was Airtex E3947M which is diferent from the one you posted? Also according to the # you gave, even Autozone says that part # will not fit a '98.

Which do I have/need?

 

[hiredgun8]

If you're gonna do the pump.. seriously consider getting a Delco pump.
In my experience the aftermarkets last no more than a couple years. ( 1 lasted 2 weeks)
I'd rather spend a little extra and only do it once.

 

[SAATR]

Yeah, I priced it out through Rockauto after getting the part # from Advance for it. Same pump from Advance is $260, and it's $150 from Rockauto. I'll definitely be going that route.

Would you still agree it's a fuel pump issue?

Also, Advance gave me a different model and said there was a difference in wiring, some are two wire and some are single wire? Not really sure what he meant but the # of the pump they gave me was Airtex E3947M which is diferent from the one you posted? Also according to the # you gave, even Autozone says that part # will not fit a '98.

Which do I have/need?

What Truckin listed is the hanger for a '96/early '97 model that is metal with a replaceable fuel pump. Late '97's and '98's use a plastic, modular style assembly whose pump is not SUPPOSED to be replaceable, but can be if you are very lucky/careful. The difference between the two pumps is going to be the three letter code on top of the pump assembly, with one having two wiring harness plugins and the other having only one. No easy way to tell which one you have until you drop the tank. Like hiredgun said, I usually recommend Delco/Delphi for pumps. I always had better luck and fewer comebacks using those than airtex/carter pumps.

Get deadhead pressure on the system by pinching the braided/rubber portion of the fuel line at the back of the motor, and see if it comes up into proper range and doesn't leak back down. If so, it's a regulator. If it still leaks, deadhead both after getting it up to pressure. If it leaks down then, it's probably an injector poppet. Just more diagnostics to make sure you have the culprit.

 

[logikfive]

That's exactly the info I was hoping to find.

I'll give it a shot tomorrow!

Joe

 

[TruckinAin4Sissies]

Whoops, mine's a early '97.

SAATR knows his $h¡T