Is This The Fuel Pump?

[lt1transam]

This is on a 2000 Silverado, 4.3, auto, only 32,000 miles. I bought the truck about 3 weeks ago from an old guy that obviously never drove it. So on my way to work this morning I noticed my speed dropping no matter if I was pressing the gas or not. So I pulled over and turned the truck off and started it again, idled fine, but as soon as I push the gas it was start stumbling, spitting, and spuddering real bad. So I get to a gas station and get my friend to tow me to work. When we get there we check a couple things. Changed the fuel filter, scanned it and a few other things. The truck would start after turning over a few times, seem to idle fine for a little while but would eventually die, especially if you even thought about opening up the throttle at all. You can here the pump rpime up when you turn the key on but I realize it could still be messed up. Any ideas?

[bill190]

If he SERIOUSLY never drove it... As in the gas could be several years old, then drain the gas and put in fresh gas.

 

I have some small engines which will NOT run on gas 1 year old.

 

So might want to ask the guy how old the gas is.

[grose67]

This doesn't really sound like the fuel pump to me. I would check the regulator to se if gas is leaking through the diaphram. Usually when the fuel pump goes, it goes quick and the engine won't start.

[lt1transam]

I have ran about a tank and a half through it at least. I topped it off with about 6-7 gallons of fresh gas when I first got it. It is strange what it is doing. Where is the FPR on the 4.3?

[Zembonez]

You need to check for fuel pressure. These trucks are notorious for fuel pumps going out. I've seen several that had similar symptoms to yours. Did the filter seem clogged when you pulled it? Did the gas smell old?

[bill190]

Where is the FPR on the 4.3?

 

If you want to work on your truck yourself, you will save a lot of money in the long run by ordering a GM factory service manual set (order at helminc.com or from a GM dealer).

 

This will give you procedures to test various things like the fuel pump, fuel pressure regulator, etc. Will tell you what the test results should be. Will tell you how to replace the parts if bad. And will tell you other things to test for a particular problem if those things test good.

 

This is the *new* way to repair vehicles. Test things before replacing. Then you don't go guessing and replacing a bunch of parts which are working perfectly fine.

 

So far as the fuel system, here is a fairly complete service/check...

http://www.asashop.org/autoinc/june98/techtotech.htm

[lt1transam]

You need to check for fuel pressure. These trucks are notorious for fuel pumps going out. I've seen several that had similar symptoms to yours. Did the filter seem clogged when you pulled it? Did the gas smell old?

The fuel filter wasn't clogged at all. Gas smelled normal as well.

[txab]

You still need to check fuel pressure

[rodz66]

I had this same problem with a GMC Jimmy with a 4.3. Definently check fuel pressure, injectors need a certain pressure to pop off. Just a little lower than recommended pressure will cause a problem. I would bet it's the fuel pump. Hope this helps.

[lt1transam]

I had this same problem with a GMC Jimmy with a 4.3. Definently check fuel pressure, injectors need a certain pressure to pop off. Just a little lower than recommended pressure will cause a problem. I would bet it's the fuel pump. Hope this helps.

 

 

I am in the process of checking everything out. I will post an update soon. Thanks for the help guys!

[lt1transam]

You still need to check fuel pressure

It won't even start now. I put a new fuel pump in there, that was easy and reasonably priced. It just spins over and won't fire at all. It was doing that before I changed the pump out. It's seemingly getting fuel. I need to check for spark, but how do you check for fuel pressure when it won't run?

[txab]

The pump will pressure up when you turn on the key. Engine doesn't need to run

[2COR517]

Will it run on ether?

[lt1transam]

I'll check those out.

[lt1transam]

I'll check those out.

Got the intake off to where I can see regulator. There is a puddle of rusty looking fuel under it and no vaccum line attached to it. Strange.