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Discussion Starter #1
6.2L Dies Intermittently - Please Help

Hi everyone - I'm getting really frustrated with my 92' GMC Sierra 4x4 6.2L w/Banks..Here's the background.

I bought the truck NOT RUNNING from the PO for a great price. He described the "problem" as "When you're driving down the road, it will just (unexpectedly) start to slow down and loose power like fuel gel, or the fuel filter is plugging up".

PO thought that the IP was bad (don't we all when we're having a problem:) ) because he had plenty of fuel pressure ahead of the pump but nothing after it.

After I had it home, I decided to replace the frame-rail fuel pump because it looked original, and the fuel flow & psi was weak at the pump...My easy fix didn't solve the problem!

Changed the primary fuel filter...My easy fix didn't solve the problem!

Pulled the bed to remove the sending unit from the fuel tank and do a screen/tank inspection. The fuel looked old and the screen had some crapola on it. Dumped the fuel, cleaned the tank & screen...Still same problem..

Changed the Injection Pump with a nice reman from USDiesel. Still have the same problem.

Just a recap of the symptoms: Normally, the engine fires right up and idles well. I have idled it as long as 25 minutes w/ no problems. When you drive down the road, everything seems fine as you're moving through the gears (NV4500) and there is plenty of power. Eventually (when you least expect it) It WILL BEGIN TO DIE, and start loosing power like it's just not getting enough fuel. This problem has happened at 1,000 rpm, 2,500 rpm, and everywhere in between.

Because when the "problem" starts, the engine looses power gradually - I have kind of ruled out the fuel shut off solenoid being bad (I would think if that closed - the engine wouldn't run very long after that?)

I haven't spent a tremendous amount of time looking for air leaks (shame on me). Could the problem I'm having be caused by an air leak? If so - is there any particular place you would suspect? I have read the detailed Air Leak "Sticky" here.

Any other ideas? I would really like to get this truck running! One difficulty I have right now is the COLD weather here. It's not been very easy to work on my truck in below freezing conditions (10-17F).

Thanks for any help
 

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Yes, an air leak could cause the problem. It doesn't quite sound like an air leak, but that would be my first guess at this point. Some air leaks are very difficult to spot and are easily overlooked.

You can check to see if there is an air leak by replacing the rubber return line that comes out of the injection pump with a piece of clear tubing. Run the engine and look at that piece of tubing. Watch for air bubbles or foam passing through the hose.

The other thing would be an electrical problem causing the engine to shut off. This sounds more like it to me... Since you do have a manual transmission, if the engine dies it won't stop spinning until the truck stops. Next time it happens, push the clutch in and see if the engine dies (make sure you are in a place where you can get the truck back home if it doesn't restart when you do it). The other thing you could do is run a jumper directly from the + battery terminal to the injection pump shut off solenoid on the injection pump and see if the problem goes away.

Hope this helps! :)
 

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I would install a fuel pressure gauge between the fuel filter and the injection pump. You will need to make it so you can read the gauge from in the cab while driving, your choice how you do that, could be with a tee in fuel line and some fuel hose to a mechanical gauge in the cab. Take it for a drive and watch your fuel pressure under load. My guess is that you might have a rubber fuel line that is colapsing inside blocking the flow of fuel. If your fuel pressure does drop at the same time the engine dies, replace all of your rubber fuel lines. I would also check your return lines to tank, a plugged return line or defective fuel cap could also cause the problem.;)
 

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What Mr. Camilleri sounds like good advice. Keep in mind, that if fuel is not getting out of your pump, it will act just the same as when fuel is not getting too it.
Getting air in the system should be giving you different symptoms than you described. Subtle, but different. With air, it would not start well - later. Also, since the major controls inside the inj. pump are hydraulic, once they get some air, they stop working correctly or smoothly.
They symptoms you describe - were very common with older - pre-1985 injection pumps when the return-fuel fitting on the pump got plugged. You'd drive down the road, the pump would run great at first, then slowly overpressurize - and power would fade slowly. Often, if you let off the gas - the engine would sit there and idle perfectly , all day long.
 

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Discussion Starter #5
Excellent suggestions men. I'll get back on it as soon as it warms up a bit. I'm really getting tired of the cold and blowing snow.

I guess the good news is that my problem still seems to be relatively minor in nature - just difficult to pinpoint and fix so far.

I'll report back after I find the "Culprit".

Thank You
 

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Good luck! :)
 

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I'm having same problem what did you ever find out???
Exact same issue?
Id look into the suggestions above, one I did not see was the tank sock being plugged, I believe sean1k7 was chasing his tail for awhile with that
ch
 

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This thread is 8 years old. I doubt the guy is going to respond.

If you are having the same issue start a new thread, but I would guess at air in he fuel. Try searching in the FAQ's for that and then start thread if you want
 
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The story goes he gave up and sold the truck to...:whistle:

Is it overheating?
 

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Let's take the Truck!
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Install a clear line on the ip return and pull your fuel cap and try again. Small stuff first. Sender rusted? Sock plugged? Filters plugged? Return plugged up? Idk. Well props for using the search feature and welcome. I would go over the fuel system a bit.
 
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