Need a little info please!!

[ccoyle]

I signed up on the forum a short time ago. This is my first diesel, and I have already done a few things to her. Replaced a few glow plugs and the glow plug relay. My next endeavor is to replace the clutch fan. Don't know what happened to it, but i can see a few ball bearings sticking out. I'm thinking it was like this when we bought it.

My biggest concern though is the fuel mileage. I am only averaging 10-12 MPG with it. Is this normal for a lifted truck and what should I check otherwise?? I have also noticed that when you are driving down the highway that the truck seems to let loose. It only does it for a second. It seems like the turbo spools and then drops off. I have never seen the turbo go above 10psi. At cruising speeds it stays steady at 5-8....I know that IDI's can be tempermental and if I could have had my choice I would have had a Powerstroke... I traded a motorcycle for it and the wife loves it and drives it more than I do. She has had one before.....

I guess what I need to know is what do i start looking for and did I get myself in over my head?? Any input would be wonderful guys...

[TurboDiesel94]

With 37's I could definitely see them affecting your mileage. What are your axles geared to? 10psi is fine, somebody has adjusted the wastegate to achieve that. If the injection pump has been turned up that can also take your mileage down. How many miles on the truck, and pump?

[ccoyle]

Originally Posted by TurboDiesel94

With 37's I could definitely see them affecting your mileage. What are your axles geared to? 10psi is fine, somebody has adjusted the wastegate to achieve that. If the injection pump has been turned up that can also take your mileage down. How many miles on the truck, and pump?

I'm not real sure what it is geared at. I know that it is about 8mph slower than what I am actually going. The truck has 205k on it as well as the pump I believe. The trans was a 5spd swap and the front axle was swapped for a solid front as well. At highway speeds in 5th gear it cruises between 18-2k rpm. Thats at what the speedo says is around 55-60 mph tho. The only way to really tell what it is I guess is use a GPS to see...

[ccoyle]

TTT....No one else has anything that they can ad???

[TurboDiesel94]

If thats the original IP then its probably time for a rebuild soon, but it doesn't seem like its giving you problems yet. You also mentioned the fan clutch, if that is not working and is running locked up that can also take your mpg down a bit too. Axle gearing can be found on a tag on the rear axle or on the sticker inside the driver side door jamb using the axle code and google.