I have a 94 7.3 idi turbo. I am getting about 11mpg on the highway or in town. I pulled a empty car hauler out of town and got about 6-7mph and it was hard to pull. I am getting about 8.5 psi of boost. Any help would be appreciated. The truck says it has 103,000 miles on it.

 

how long has it been since you changed fuel filter & air filter?

 

Start with the basics. Make sure you are getting air and clean unaireated fuel to the pump. Start there first.

 

all the basics are fine.

 

Do you know if the injectors and injector pump are original?

Are you getting any smoke? If so, what color, and under what conditions?

Have you checked for any exhaust leaks?

 

Mine is an 86 with 126,000, just by changing the o-rings & return lines my power went up & so did my mileage.

 

I believe pump and injecters are original
I get the normal black smoke from diesels but i get lots of whitish blueish smoke at very low throttle conditions.
I havent checked for exhaust leaks. I will check

What o-rings did you change?
I was planning on blowing out my return lines. Should I just replace them?

 

i would replace my lines and caps with a kit, they are around for about $30

basic mantanance is good to do but has the truck been timed at all? that can help big time. as the pumps wear they wear to the retarded side. when i had mine timed it went from being down in 3rd (5 sp) on a good hill at 45 to holding in the 70's and no shifting.

 

Unless you are seeing high oil consumption, I would tend to agree about timing being a possibility.

If, however, you are seeing oil consumption, then I would clean the CDR valve by removing it, and soaking it in gasoline for a while.

From what I have heard about the turbo IDIs, there really shouldn't be much black smoke once the turbo spools, so I would check for leaks in the turbo plumbing and intake as well. It doesn't take much, to blead off boost pressure, and the waste gate could be compensating, but overall, the amount of air getting into the engine may not be enough for the amount of fuel, even if you are seeing 8.5 psi.

 

what is the correct method for checking the pump timing?

 

Yes, by all means replace them. Under the plastic snap on connecters are two o-rings that harden up & lose their seal. If you are going through all the trouble to take them apart, in a few more minutes time you'll be brand new.

You'll need a pick with a hook to get under them to get them off

 

thanks i will give them a try

 

sds2000,
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