Need Help Diagnosing Fuel Delivery Issue

huskerfan said:

Well I tried again last night - got it fired up and still the same problem. Installed the clear hose like mentioned, and there was not an air bubble when it was running. Only after shutting it off did a small bubble form.
View attachment 948910Next i tried cracking injector lines while it was running and had about 20% throttle. It would idle down each time i cracked an injector line, and spurt from the hose under pressure, then would idle back up once i tightened the nut (understandable i am thinking since then there would be pressure back in the system again):

IMG_0982.MOV

drive.google.com

You can see below that there is a bit of rust inside the governor housing, not sure that that matters since the fuel looks clean? Fuel Wouldn't be too old or anything. Within the last year easy

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It just seems to me like the IP is running and working but there is some other small issue causing the timing to be off? Or maybe i am wrong and this is a key symptom of an injector pump going out?

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Does that governor sleeve even move?? That is very rusted shut. It would make sense why it shuts off now.

WWRD99 said:

Does that governor sleeve even move?? That is very rusted shut. It would make sense why it shuts off now.

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Yes it does, it just doesn't go back after hitting full throttle - video below:


I thought the metering valve was sticking, but after pulling off the injection pump and then looking at my buddy's injection pump on his 6.2, i am not sure what causes the metering valve to close after you let off the throttle because his does not seem to close either after letting off of the throttle? Video of his IP below that is a lot cleaner than mine:


I thought there would be a spring around the metering valve that would cause it to pull back shut when you lift off the throttle, but after pulling out the governor allen head bolt, there was no spring around the metering valve once i removed it. Does anyone know what causes the metering valve to close when you let off the throttle? I was just going to swap this IP from my buddy's 6.2 into mine, but if the linkage on it moves the same as mine, it seems i would have the same issue....

Well guys finally got the other IP swapped over that came off my buddy's donor 6.2

Was able to get it to fire up right away after swapping it over and now it will stay running and not die after letting off the throttle.

Only weird thing was the first time i got it to fire off, it acted like it wanted to run away, but i turned the key off and it shut down. I was cautious to get the fuel shutoff solenoid on the correct way so as to not have a runaway engine, pulled the cover off to double check and it was on correctly. So i fired it back up again and it seemed better, chalked it up to excess fuel in the motor. It would still sometimes die after letting off the throttle though.

Anyways i had the IP kicked about a matchbook cover to the drivers side initially per the recommendation on this site from the gent that did the forum writeup about swapping an IP. It idled rough though, so i kicked it about 1/8th of an inch to the passenger side:

Now it doesn't die when you let off the throttle, but it still is idling rough. It almost seems like it is "hunting" for the sweet spot when it is at idle. Revs up and down a bit trying to find a happy place. Video below, hard to tell that it is idling rough though, more so proof that it is not dying once i let off the throttle anymore:



Do i need to kick it more to the passenger side? Or back to the drivers just a bit?

Try lining the marks up straight across and see how it does. Here is a video about different ways to check the timing:

Your friends IP marks are for his car, not yours.

Morning Gents! Well i have been stumped on this, i was gone for a week over the 4th, and am back troubleshooting this puppy.

I had it about 1/4" retarded and thought i would take it for a test drive. It seemed to be going great and was not dying once you let off the throttle, but it would die whenever i came to a stop. Would fire right back up though no problem.

My buddy mentioned to me that the 6.2 he bought that he gave me the IP from had a turbo on it, so he was assuming the fuel was turned up on the IP. That being said, last night i backed off the fuel screw via the side inspection port a little less than 1/4 of a turn thinking maybe that would help.

I am not sure how much they had it turned up when they added the turbo (boy was that a PIA doing it via the side inspection port and a dentist mirror LOL)

I cracked all the injectors and cranked it til i had fuel at each one, then tightened them all and it fired right up, but was idling rough still. Tried advancing it about 1/8" past the mark on the housing, not much better. Tried retarding it 1/8" past the mark on the housing, not much better.

I am going to mess with it some more tonight as i have a river trip this weekend i need it operational for. Worse case scenario i spose i can get the fuel turned back up and retard the pump just to get it operational for the weekend as it will be mostly low slow cruising and if it dies every now and then that is manageable.

I guess i am not sure if i should try turning the fuel up or down a bit more and then mess with the timing? I feel like i am getting close here, but not sure if this is normal trial and error or not?

Also, am i able to adjust the fuel screw via the top of the IP and fire it up with the cover off? or would fuel go everywhere? Seems like adjusting the fuel screw from the top would be a lot easier than via the side inspection cover if i have to do it multiple times....

Are your glow plugs functioning? A cold 6.2 will not start without them. Just a thought. From what I read you have fuel to all the right places. Second issue in my mind is injector pump bad or check valve stuck.

Little update for everyone on this for some closure. Went to adjust the fuel screw back up 1/4 of a turn, but this time i did it via the top of the IP just so I knew how to do it for future reference. Pulled out the governor, made the mistake of bumping the starter to rotate the IP to get access to the fuel screw instead of barring the engine over by hand as i wasn't thinking correctly and was just going through the same steps as i did when adjusting it via the side inspection port and boy that was not fun. It fired off and ran away on me. Took about 95 rags stuffed into the intake before it finally idled down but still wouldn't completely stop, so then i cut the fuel supply line by the fuel pump and it finally stopped running. Whole debacle probably lasted about 5 minutes. Came out of the garage coughing looking like Willie Nelson coming out of the closet after hotboxing it.

That was scary. Lesson learned. After all the smoke cleared out of the garage, i adjusted the fuel feed screw back up 1/4 turn and found out it was indeed bottomed out, so then i backed it off 1/8 of a turn and made DAM sure the governor was in before i fired it back up again. Low and behold it all of a sudden ran perfectly. Timing was about 1 width of the line advanced. Drove it around and no more dying when i let off the throttle. Phew. Thought the problem was solved just in time for the river trip that weekend. Ran fine in the river, but then at night it died and couldn't get it to stay running in order to make it back to camp. Had to have a buddy tow me all the way back to camp. Started trouble shooting in the morning, after about an hour i realized i hadn't pulled off the return line check valve on this new IP to see if there was any debris in there. Sure as shit, it had some black bits in there that was preventing fuel from passing through. Cleaned it out as best i could and then it fired right up and ran like a top for about an hour, then same problem again. So then i pulled off the fitting and broke the glass ball inside with a hammer and an allen key. Then it ran absolutely flawlessly the rest of the weekend.

Only issue i am having now is when it first fires up, the first time i give it some gas, it almost sticks at that throttle position even after letting off the throttle. But then i shut it off and fire it back up and the problem goes away. So i need to look into that now.... always somethin. Appreciate everyone's help on this issue!

Please post a picture of the fuel feed screw with the screw circled, I have a smoking issue under acceleration also on a newly rebuilt pump.

deank said:

Please post a picture of the fuel feed screw with the screw circled, I have a smoking issue under acceleration also on a newly rebuilt pump.

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Check this link:


You can see the fuel feed screw here via the side inspection port on the injection pump