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93 Chevy 6.5 turbo diesel Manual injection pump problem

Diesel Nut

Diesel Nut

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Messages
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Location
Fond Du Lac, WI
The injection pump was rebuilt just over a year ago and I put new injectors in not the cheep Chinese crap injectors. The truck starts great and has power. When I'm going down a hill or on flat land, cruising the truck sometimes surges. If you snap the throttle it stops and will run fine and do it again in a little bit. Never does it going up a hill. There are no fuel leaks at this time. Has anyone else had this issue?
 
Leaking metering valve, or air in the fuel. Sometimes more internal timing advance helps .
 
There is a timing retard cam on the pass side of the pump. Somebody may have adjusted it to far onto the retard ramp.
 
Unsure of psi when this this is going on. I'm planning on putting in a fuel pressure gauge this winter. I'll see when the weather breaks what the psi is, I dont drive this truck in the winter due to the condition of the truck and salted roads.

Is the retard cam the one that moves with the throttle? How should you adjust the cam?
 
Yes, it has a pinch bolt holding it to the throttle shaft. This will adjust idle and part throttle advance. There is also adjustment at the bottom of the arm,got to be careful with that one , it changes timing everywhere.
 
I have two 6.5 mechanical injection pump engines. Both 1993 the one fired up at -5 last week without being plugged in and purred like a kitten. My dually which im having issues with you have to snap the throttle even when it is 60-70 degrees out so it will idle but runs fine after a minutes. It has a lot of unburned fuel at start up. I'll have to check the cams on both trucks. I know my dually I've had to move the injection pump to the passenger side to make it run as good as it does. Timing chain and gears are correct I've pulled the water pump to check.
 
Diesel Nut said:
My dually which im having issues with you have to snap the throttle even when it is 60-70 degrees out so it will idle but runs fine after a minutes. It has a lot of unburned fuel at start up. I'll have to check the cams on both trucks. I know my dually I've had to move the injection pump to the passenger side to make it run as good as it does. Timing chain and gears are correct I've pulled the water pump to check.
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This sounds similar too the situation I have with my 94 that I have just grafted a DB2 onto. Some here have put forth the idea of lift pump pressure being too high as I was running a Cummins lift.
I've replaced with a stock E3158 Airtex lift, and in process of adding fuel pressure gauge. Have to pull pan and reconfigure tranny cooler so will be another couple days before I'm ready to fire it up. Will let you know what happens then. Currently the pump is advanced all the way to the driver side (you mentioned yours is retarded)to run. Smokes white heavy at startup, clears up after 10-15 seconds of keeping foot lightly snapping throttle or will stall. After that will idle fine all day long. If the lower lift pressure doesn't correct the problem, I'll be taking the truck over to my local Stanadyne shop to have them time it. Hopefully they will be able to get to the bottom of the problem. Either way, I'll report what happens.
 
When I snap the throttle it is to set the high idle. I noticed that if I try to advance the throttle the engine has a harder time starting. I'll be interested to hear how yours turns out. I wounded if there is a issue in the injection pump. Thanks for the info.
 
It is customary on mech inj stanadynes to at least bump the throttle during a cold start. Usually while the glows are cycling before the engine fires. This helps the energized fast idle solenoid to engage.
 
I found some information on the DB2 4911 injection pump. Looks like from what Stanadyne says it looks to be a stuck metering valve. I'm going to see if I can replace the metering valve and where I can get a metering valve.
 
Pulled the injection pump and put another injection pump on and the truck starts and runs great now. It was the injection pump with my truck. Still interested to hear what you find out on your injection pump Yachtcare.
 
Diesel Nut said:
Pulled the injection pump and put another injection pump on and the truck starts and runs great now. It was the injection pump with my truck. Still interested to hear what you find out on your injection pump Yachtcare.
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I'll post results in my thread "Fuel system bypass filtering".
 
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