I have a '97 4wd 2500 6.5 Suburban with 190,000 miles on it. I'm the 2nd owner, I've had it for 5 years and use it mostly to drive from the city (Atlanta) to the mountains (Mineral Bluff, GA) and to tow a small trailerable sailboat. I have an exhaust kit, a reprogrammed chip for fuel economy, injectors, and a turbo governor (maxetorq) all from Heath. When I first got the truck I took it to a local diesel place and asked them to give it a "once over" and they told me that the turbo would be far more effective with a working solenoid (!!). I thought they gave me compression figures on each cylinder but I can't locate them. I get a fair amount of blow by, using the old fashioned test of loosening the oil filler cap while the engine is running, it hops up 3 - 6".

I get about 10mpg no matter what I'm doing - towing, not towing, driving on the highway, driving in town. Based on results in other posts I feel like I should be getting more in the 15 - 19mpg area. I don't remember what my rear end gear ratio is, I can check the code sticker in the glove box. My mileage has been consistent through different tires too (I'm currently running Yoko Geolander ATs on a stock wheel, normal size).

How much of a difference does the injection pump make to fuel economy (I would imagine it could be a lot) and how would I be able to tell if it's time for a new or reman injection pump?

What should my cylinder compression generally be before I start thinking that it's time for a rebuilt motor?

 

Your not the only one, My 1995 K2500 truck (6.5 Turbo) with 3.73 gears get 10.8 MPG. On that tank I drove city, highway, and pulled trailer. I realize that 2/3 things I did cause bad MPG's, but I didnt think it would be that bad.

 

i read on another thread someone posted that cylinder pressure should be at least 400 psi.. i'm not sure, just throwing around 2 cents