6.2 injection pump

[chester247]

6.2 injection pump
what does the return line check valve in the top cover of the injection pump do??

 

[Westech]

what check valve? The line in the top of the pump is for the cold start timing advance. post a pic and I can tell you 100%

 

[chester247]

thanks
the fitting that the return line connects to on top of the injection pump .

 

[chester247]

also can i replace the orings on the ip without removing the pump ?
i see some fuel is leaking from the pump into the valley on top

thanks

 

[Westech]

what o rings? you mean the sleeves on the Throttle shaft?

 

[acmunro]

check valve

It plugs up and then the truck will not run, at least that is the case on my M1010. I need to get around to changing that injector pump.

 

[Westech]

plugs up? with what? If you have a good fuel filter it should just be clean fuel in there and nothing to plug up.

 

[acmunro]

Better check the text book teach

Better check the text book teach, I have clean fuel to the IP. On 1985 and older 6.2's the Governor weight retainer ring breaks down when subjected to water in fuel or alcohol. I thought I could get by by cleaning the check valve and pulling the top of the injector pump and cleaning, but no dice in my case. I don't know how large the retaining ring is, but it sure makes a lot of crap.

 

[Westech]

Ah I never herd of that before. Well there will be a point when that ring just goes south and its all over. I would just replace the pump. you only have to take off the intake and the oil filler tube to do it (done it). I see them on egay all day cheap. I don't know if its worth the hassle to rebuild it rather then replace due to the low cost of the pumps.

 

[acmunro]

I learned the hard way, truck lost power and stopped running completely. First thought was replace the fuel filter. I did and it almost started, but did not. I did some research and found out about the retainer break down problem. I removed the check valve and used carb cleaner got some crud out. I put the check valve back in and it started right up. It then stopped running. I pulled the top off and cleaned a lot of junk out of the IP. Ran good for a while, but again it stopped. To get it home once I put a barbed fitting in and an old style fuel filter to catch the debris. Made it home, but long story short. I need to replace that pump.

 

[Westech]

That really stinks. Something so small like a little water will take out that pump. The military replaced my filter this year but now I kinda want to replace it just to know I have done it.

 

[chester247]

I think i will replace the injection pump
rather than try to repair it

i cleaned the check valve ,engine started right up ran for about 3 min stalled
did this about 4 times

so i removed the check valve and removed the glass or what ever was inside
engine starts and runs fine
but i notice fuel is still leaking

thanks

 

[acmunro]

Sounds like a good idea to replace the IP. I noticed my M1010 surged and didn't run too good without the restriction of the check valve. I think the check valve controls the ignition timing. I heard when the check valve plugs off completely the timing is advanced too far to the point the engine will not run. I would then think if there is not any restriction the timing would be slow. Not sure about that. Anyone else know ?

 

[dilvoy]

I think your check valve was sticking. It controls IP timing via the amount of fuel returning via the Fuel return hoses from the Injectors.

 

[scottc]

GM originally used fiber parts in the pump. Not sure what parts. They break down and clog the check valve. If it gets rebuilt they will not reinstall fiber parts. If you buy another pump that has not been rebuilt it will do the same thing in time. Had the same problem about four years ago. At that time having the pump rebuilt was considerably cheaper. Good luck.