RK4332

Hi,
My 92 Jimmy has 200k on it. It runs good when its cold, but after driving it for a longer trip, it will stall. After it stalls, it will usually start back up, sometimes it needs a shot of starting fluid, and its fine for about a couple minutes, then cuts out again. Yesterday, it left me stranded and i had to get it towed. It wouldnt start back up. The starting fluid would fire it, but it would die right away. When the tow truck driver unhooked it, i tried it again, and it started right up, and ran fine. I've replaced the fuel filter, and the fuel pressure regulator. A mechanic looked at it, he said my fuel pressure is fine, but i'm wondering if i should have it checked again. i figured before i do, i'd see if anyone else might have had this problem, or knows about it first.

MT-2500

What engine?
Any check engine lights or codes?
Re check the fuel filter and fuel pressure?
Put or tape a fuel pressure gauge on outside of outside mirrow or outside of windshield it and drive it till it stalls or acts up and watch the fuel pressure.
Post back engine and fuel pressure.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

RK4332

Ok, First, its a 4.3 Vortec CPI. I just checked the fuel pressure, and it read about 52 PSI at an idle. When i gave it gas, it went up to about 64, and back down. I tried holding it at about 3.5k RPM, and the fuel pressure stayed at 64 PSI, but it acted like it had a governor in it, sputtering and trying to stay at the high RPM. I should note that my fuel pressure regulator was broken, and i screwed a guage from a tire regulator on it. I dont know how accurate that is, but i guess PSI is PSI.

Also, there is no check engine light on, or any codes.

MT-2500

Revving the engine up sitting still does not tell us much.
You need to catch it in the act of acting up.
Make sure you gauge is reading right.
Then hook the gauge up and drive it until it acts up and then watch and check the.fuel pressure.

__________________
Remember proper testing gives us the answer to many problems.
MT

RK4332

Thats not easy to do with a hood in the way.

MT-2500

No but where there is a will there is a way.
There is usually a spot you can get the hose under the hood or you can tap in at fuel filter and come up the side of it.
Just tape or tie it down good.
I do it all of the time.
Good luck
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

RK4332

Ok, I decided that with 200k on it, it wouldnt hurt to put a new fuel pump on it anyway. That seemed to be the stalling issue. It idles nice and smooth, and the fuel pressure is good now. I also installed the T after the fuel filter, and drove it, and it stayed around 65-67 psi. I think i'm good there, but it still boggs down when i give it gas. At first, i thought maybe a bad TPS, but i think that would throw a code. At this point, i've replaced the fuel pump, fuel filter, and pressure regulator. I hope the next part is a cheap one. lol

MT-2500

Fuel pressure specs is 54/64 on it.
The only time you should see up to 64 is starting or no vacuum or full load.
Running on the road you should see around 58-62 lbs.
Have you checked the cat back pressure.
A plugged cat can raise fuel pressure to max from no/low engine vacuum.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

RK4332

I havent even thought about that, but i'd be willing to bet its got the original one on it. I'll try that tomorrow.

RK4332

Hi,
First of all, thanks for the help MT. I just wanted to post because i found the problem incase anyone else comes across this. The PCV valve was bad.

MT-2500

You are welcome and thanks for posting back how it went and what you found.
Glad all is well now.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT