Fuel Economy

[Tom Hallock]

I have a 96 Chevy 3/4 ton pickup and I'm getting lousey mileage. Last year I would get about 300 miles to the top half of the tank with a little more added carrying it over the top, an by the time I had to fill up again, when it was about 4 -6 gal from being empty, I'd had about 416 mile per gal. Now I'm lucky if I get 300 miles to the tank. Lift gate works fine, fuel filter, new, new K&N air filter, #2 diesel. So what gives. I am driving in extremely hilly area, Jefferson City MO. And have stalled many times as stated in previous articales, though engine strarts right up again, usuallyan haven't been stranded anywhere, ( hope I didn't just jinx myself) yet. And, yeah its cooold here, 10 degrees last night. Hut , hell I wasn't getting very good mileage in El Paso Tx an its pretty flat there.
So, what gives?

Tom Hallock

[Tom Hallock]

Sorry that should read 416 miles per tank

Tom

[DILLIGAFRI]

I have been running about 16mpg in the city and 20 on a long highway run. Stock 6.5 98 K1500 ex cab

[DmaxMaverick]

Is this just one tank you are talking about, or has this been happening over several tankfuls?

If you got fuel in MO, it may be winterized blend. If so, expect a mileage drop anywhere from 5% to 20%.

[Marty Lau]

Originally posted by Tom Hallock:
I have a 96 Chevy 3/4 ton pickup and I'm getting lousey mileage. Last year I would get about 300 miles to the top half of the tank with a little more added carrying it over the top, an by the time I had to fill up again, when it was about 4 -6 gal from being empty, I'd had about 416 mile per gal. Now I'm lucky if I get 300 miles to the tank. Lift gate works fine, fuel filter, new, new K&N air filter, #2 diesel. So what gives. I am driving in extremely hilly area, Jefferson City MO. And have stalled many times as stated in previous articales, though engine strarts right up again, usuallyan haven't been stranded anywhere, ( hope I didn't just jinx myself) yet. And, yeah its cooold here, 10 degrees last night. Hut , hell I wasn't getting very good mileage in El Paso Tx an its pretty flat there.
So, what gives?

Tom Hallock If it's PMD it will get worse on the stalling. Better fix it. As far as MPG, how many miles, do you have a soot trap, changed the injectors? How about your timing chain and gears? L56 or L65 engine? 34 gallon or 26 gallon tank?

[Tom Hallock]

In the three years I've owned it, I've had I think 3 injectors changed, fuel pump changed, harmonic balancer changed, 1 piston changed and all the bearings replaced. Was told that when the upper piston broke, the bearing in that cylinder (?) had to be replaced, it was suggested that I might consider replacing all the bearings in the engine and with what little I know about engines of any kind, I agreed. Have been in an out of shop numerous times for stalling though nothing ever shows up as checking engine. OK, its been suggested that I change fuel pump and also that I have ignition fuse checked.
At present time, I am unemployed, actually retired but injured from a fall and at the present unable to work. My wife does work so that helps an awful lot. And hopefully we will be moving to one of the southern states with much warmer climate.
Miles on truck are about 193,000 and its a 96, 6.5 diesel pickup with extra cab, two doors. Have no idea what an L56 or an L65 is, sorry but a mecanic I ain't. I was lucky to put in my K&N filter without help.
I do know that the previous owner had the engine changed out after 20,000 miles an the mileage was at 49,500 when I got it, why it was changed I have no idea.
Tom
PS -- While I was having bearings changed, I figured it was a real good time to replace the Glow Plugs too for as far as I know they had never been changed.

[Marty Lau]

Tom;
Injectors are recomended to be changed after 100,000 miles. If you have had 3 injectors changed that is an indication that they have exceeded their efficant life. Most Diesel mechanics suggest to change the whole set rather than peice meal unless the rest are low miles and you have a "bad" injector. When did you have your Injection pump changed? (new PMD)
The reason I asked about the L56 is that engine has a soot trap and they get plugged and create extra back pressure which reduces power and MPG. If you have 6 bolt wheels you may have a soot trap which has a expected life of 80-100,000 miles. So replacing the soot trap.......can help some folks have removed them, and I would never suggest that. ;) If your stalling is the PMD/FSD some have tighed the 4 nuts on the back of the PMD and have regained usablity, that has only been a short term fix for me. (like 7-10 days) The problem if you PMD is on the pump they are a pain to remove to tighten the nuts.
Hope this helps.
In reading your post again I notice you have not changed IP but it's been suggested. I'd bet you lunch that you PMD is dieing it's slow death. So if the IP was changed at 20k with the engine then you have about 175K on the IP not too shabby. Call Bill Heath and chat with him and see what he thinks and what he will do for you on a PMD issolator kit. It easy to install about as reasonable of a PMD fix with a 7 year warrentee. If that don't fix it I owe ya lunch(within reason).