Fuel Mileage in my 92

[Johnny]

When traveling on the freeway I used to get a little over 20 mpg (22-24).
Last trip was only 16. What should I look for to improve it?
Truck has about 210,000 miles on it. Auto, 4x4.

[RoadWarrior222]

Check your plug gap... just kidding... but maintenance? Air filter, Fuel filter(s) etc?

[440dart]

just like meantiond above filters ect and try to drive around 1750-1850 rpms

[trannybuster]

Id hit up one of the diesel forums...

[Johnny]

Fuel filter changed. Air is K&N, but guess I had better check it and clean it.

[RoadWarrior222]

Didn't you have construction and gravel road detours a few months back? Could be caked with dust.

[Johnny]

Yes, I'll check it of course. But I do not drive it daily, only to haul something or to tow something. So it never saw that construction.

[turbovanman²]

Could be a bad tank of fuel.

Of course, these older ones are pretty choked up, nice exhaust helps, the fuel injection pump mods also help with mileage. Do you have the killer dowel pin fix done?

[Johnny]

Have large exhaust

Fuel injection pump mods, but not dowel pin fixed that I know of.
Dont know if the original owner did it.

[turbovanman²]

So could be bad fuel or maybe the injectors are worn out, pump worn out.

[Johnny]

How would I know if the injectors were worn enough to need changing?

[chryguy]

Hey Johnny,

The only way to know for sure is to pull them and take them to a Diesel shop. They'll check them for flow and pop-off pressure.

CG

[Johnny]

....or just get new ones anyway as it has been enough miles?

[RoadWarrior222]

If it had fuel sitting around in it for months at a time, I'd figure it was something a bit gummy and go through my "chemicals" cabinet, quart of mineral spirits, quart of kerosene, 5 gallons of fresh good brand diesel on top, possibly a quart of converted bio-diesel (Search Dr Pepper method) if I could be arsed, cup of ATF, half a cup of TCW3 (Marine ashless 2 stroke oil) and run that out at high revs, italian tuneup style.

[turbovanman²]

....or just get new ones anyway as it has been enough miles?

I would say its time to check them or replace them. Now what to use is a whole new can of worms, If your looking for more oomph, I would get a "stage1" per say, some offer better fuel atomization etc but who to use, no idea.

[Subliminal]

Hey Johnny,

Could be a million things, as listed above. Also, and I'm sure you know this, but taking your time filling up can be the difference of several gallons in your tank...they tend to foam a lot and when the pump clicks off sometimes you can cramp 3 or 4 more gallons in the tank. Have you checked your mileage again, over several tanks, or just that one?

I replaced my injectors a while back. Went with 'Bosch 190's. So called 190s because they're supposed to give you 30 hp over the stockers. They are actually smaller, but they atomize the fuel better. I think I paid under $300 for all 6 of them and then made myself a homemade puller with some pipe, all-thread, a few nuts and a welder.

But, I wouldn't discount fluke before you measure over a few tanks.

[Johnny]

Did the new injectors help mileage or power?

[Subliminal]

Ha...Honestly, hard to say. Back when I changed them out I changed out my injectors, turbo housing, transmission and tuned the fuel pump in close proximity.

In retrospect, I wish I would have done it a little more scientifically. Durp.

[MOPAR2YA]

Johnny, you can get some 50 h.p. injectors which will make it run better, but as with any larger injector, if you put your foot in it it WILL use more fuel. I put well over 500,000 on the stock injectors, but always changed filters and ran additives (Howes)...