My LB7 fuel economy way down

[cmwilga]

I have a 2002 LB7 with 80,000 that is only getting around 13 mpg now. When it was new I was getting around 19 mpg. I noticed the economy going down about a year ago. I just recently had 8 new injectors installed due to diesel leakage into my crankcase. I thought that the bad injectors may have been the cause but it wasn't. You guys have any clues as to what may be causing this costly problem?
Thanks,

[Mark Rinker]

Yours would not be the first LB7 to receive new injectors, and have a significant drop in mileage.

However, make sure you first rule out the following:

Dirty or collapsed air filter or intake tube
Underinflated tires
Dragging brake(s)
Inoperable or low boost turbo (exhaust leak, WG stuck partially open)

[cmwilga]

Air filter is good,tire PSI good and brake is good. No exhaulst leaking. I have no idea how to check if the WG is stuck open or where it is. Thanks for the info though.

[Mark Rinker]

If your power/acceleration is normal, and little to no black smoke in the rearview under acceleration - you can safely assume your turbo and wastegate are operating normally.

[gmdieseldan]

Hi Do you still have the cat. in the exhaust? may be pluged? May not enough timing, reflash the computer? DAN

[StrangeEngine]

I have a 2002 LB7 with 80,000 that is only getting around 13 mpg now.

That's about what my '02 has gotten from Day 1. 13-14 around town and 16 or so on the highway at 70-75mph. 72K miles on it at the moment.

Sounds normal to me.

- Mark

[SoTxPollock]

Doesn't sound normal to me. Look at the fuel mileage poll on the early LB7's.
Of course your right boot may be heavy, and if you do a lot of stop and go. My lifetime average for 100,000 miles is probably 18. I'll have to check the log book and verify that, but its probably real close.

[cmwilga]

Appreiciate the info guys. I had 245-75-16 tires when I was getting 19 mpg. I am running 265-75-16 tires now. I don't think that would make that much of a difference. I may just have to jump on one of them 2007 new body style 4 door 4x4 Duramax diesels :D and trade the guzzler in. I got the fever real bad right now.:rolleyes:

[JohnC]

I had 245-75-16 tires when I was getting 19 mpg. I am running 265-75-16 tires now.

Did you correct the odometer? Your mileage may be better than you think...