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Lost my MPG

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Clutch Master Cylinder Pushrod Play

Ag injector pump

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Lost MPG after VE injector pump rebuild. I’ve had good experiences at NTG Racing up till now. Time to rebuild the injector pump so I took it to NTG Racing, it was leaking bad. I just ask for good mileage and no performance up grades. I was hoping that it might improve my MPG of 16. They sent the pump out to Omega for the rebuild. Got the truck back it seemed OK until I filled the tank and checked the mileage. Holy crap 12 MPG. I have never got that bad a mileage before. It was always around 16 MPG . Well took it back so they could figure it out. They gave it back to me after some adjustments to drive, wow now I could watch the fuel gauge move, 9 MPG. I took it back, they were stumped. They checked other components. “Everything checks out fine. “ Its got to be the injectors,” OK if that fixes it I’ll pay, if not I won’t pay for them. They didn’t change the injectors. They drove it and adjusted the fuel screw on the pump (per the rebuilder Omega) that brought it up to 10.5 MPG we’re not even back the 12 MPG I got at the first try. So is it the pump or is it the injectors? I removed the injectors and had then tested (Advanced Diesel) they tested OK, not the problem. As they had a little over 100,000 miles on them I had them rebuilt. Reinstall them and no change. NTG took the pump out and had it tested (Express diesel) a Bosch Certified center. The pump was taken apart and inspected. Not all the worn parts had been replaced. But still OK . Reassembled and ran on their test machine and readjusted to factory specs 1.25 then advanced to 1.45. Reinstalled ( with a dial indicator) in the truck and now I have it back. It seems ok, a little less power. Put some freeway mile on it and I got 12.65 MPG. Not the decent MPG I had before the rebuild All I want is my 16 MPG back. I’m losing 4 to 5 miles per gallon that adds up quick. What have they done to my truck? And they are still stumped. I still think it’s the timing. Joe said he doesn’t want to see the truck again. Now what?
1992 w250 auto, gauges, 16cm 4" exhaust the rest stock 103,000 m
 
I not sure, the pump was taken apart and inspected put back together and tested and set to factory spec. I'll ask them.
 
My guess you got crap parts like the pump I got from DCP on E-bay id go to Cummins dealer in your area if it was me
 
I went back to Express diesel who had taken the pump apart and ask them. Everything was Bosch no crap parts.
Still searching for the answer. What did they do to my truck ???????????????
 
Ask them if when they pulled the pump off and reinstaled the pump if they did it with the timing cover off or on ? if they didnt lock the pin
they might have the timing retarted too much and if you have it off you can fix the KDP while in it
 
All I want is my MPG back
I don't think the cover was off, I ask them about doing the KDP and was told it wasn't exposed. As far as timing, I don't have any smoke so I think its OK.

Bill
SOCAL
 
New or not if the fuel pin is rotated to the wrong spot it will change how the pump and the whole engine performs, same if the star wheel is miss adjusted
 
The the pump was disassembled and inspected at the Bosch service center. Reassembled and adjusted to stock spec. and tested on their machine. It checked out fine. Still looking for the answer.

Bill
SOCAL
 
I bet your timing is off , timing wont affect the smoke , im not talking pump timing but the gears if its not were it was supposed to be in some cases it will smoke if its fireing way wrong my guess your a notch off at the gear
 
yes because that timing is just for the pump, if the engine wasn't locked with timing pin or they moved the engine some how it could have moved, lok up some of the kdp stuff it will show how it could move
 
yes because that timing is just for the pump, if the engine wasn't locked with timing pin or they moved the engine some how it could have moved, lok up some of the kdp stuff it will show how it could move

I was told that if that happened it would smoke and I don't have smoke. So I don't know what to think.
 
I think its time to go to another shop and if its a screw up on there end get the proof via photos and written statement then have them pay . Is there a cummins dealer there id go there,
yes it would smoke depending if it was way off , but ifits the other way I say no unless your injectors are bad
 
I think its time to go to another shop and if its a screw up on there end get the proof via photos and written statement then have them pay . Is there a cummins dealer there id go there,
yes it would smoke depending if it was way off , but ifits the other way I say no unless your injectors are bad

I have talked to several other shops and they don't know what it could be. Try this try that. The mech. that installed the pump had worked at the Cummins shop & is very good. The injectors have been rebilt & retested. I don't want to start adjusting the pump and voiding any warranty on it. The pump was stock before the rebuild so I don't know what to think. Thanks for all the impute.
 
The only other thing i can think of is 2 more things ; Did you ask the intial shop that did the work if the timing pin on the engine was locked with the pin and the engine didnt turn and there a 100% sure of it . The other thing that could be going on is may be its sucking a tad bit of air some place are all the injector lines good and snug ? Even though they never touched the actual fuel line from the tank maybe the " O" rings in the fittings are getting bad , i cut mine off and just slipped good deisel grade fuel line over the plastic hose now it starts way better than before . Also maybe your lift pump is going bad . Did they change your fuel filter ? also how is your air filter ?
Id also try a few bottels of howes or lucas fuel conditioner in it , also a few ounces of 2 stroke oil wouldnt hurt . You might try getting your fuel from a diffrent station and see what that does .
 
I was told that the engine was locked in place, they checked for air leaks, none. The truck starts right up. Lift pump, maybe ? Air filter new, fuel filters just changed before the pump rebuild. I am trying a fuel additive in this tank, got the fuel at another station. Haven't tried the 2 stroke oil. What would that do? I drove my 93 d250 Cummins today what a differents, way more great up and go. Its got twice mile on it and is stock but a 4" exhaust. I know 1 a w250 and the other is a d250 but what a differents. I'll keep trying. Thanks
 
When I changed the VE on my 91.5 a few years back, I got a set of instructions off this site that covered it real well. Thinking back, I pulled the timing cover to do the KDP fix at the same time, so I could see the gears and timing marks. Seems like the was a little gear lash and you had to rotate the pump housing to set the preloaded on the timing gears. Once at this was done and the pump bolted down, you unlocked the pump. Instinct says Donovan is right, timing is off. If you are getting air in the lines, you will see bubbles when you bleed it off at the pump. What does you fuel pressure read? How much boost is it making at WOT? Did you check other things like a brake dragging, that will drop mpg a couple numbers but not that much. If it were mine, I would verify it is getting good fuel pressure, then pull the timing cover, fix the KDP, pull the pump and have it timed and locked, then reinstall it, verifying the timing. What was the reason for rebuilding the pump, was it leaking or something else?
 
Question : If the pump is set with a dial indicator can the timing be off. I don't have smoke.
Brakes not dragging, boost about 18, I'll check again, not sure on fuel pressure, I don't have that gauge
 
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