Loosing Miliage $$$$

[subway]

got my truck timed by a good member of this board, thanks Mel and it ran much better after and my miliage seemed to signifacantly improve but now its dropping again. right after it was timed i avaraged out around 16mpg running only about 1/3 of the tank properly timed. figured i should really see an increase in the next tank since it is timed and i could get a good reading on miliage. filled it up and it showed i got about 16.5mpg . ok maybee i was enjoying the new power to much so i took it easy on the next tank 13.5mpg

so my question is what could be causing this, it feels good power wise just loosing milage. it does smoke more then it used to? i suspect it could be injectors seeing as i think them and the pump are original with 165k on them. i cant just throw parts at it though, i just stretched a couple of weeks ago on it with all new front breaks and glow plugs. anyone close have a pop tester

 

[Squirreltow]

Mel has a pop tester in his possession. Might be time to arrange for another group meeting as I am sure PaFixitman would love to have some help completing his truck.
Not sure about the drop in mileage, but I know that the timing being tested and fixed was a very good move.

 

[adrianspeeder]

Well ya better tighten that mileage back up... Wouldn't want a loose mileage to fall off and hurt someone.

 

[subway]

Well ya better tighten that mileage back up... Wouldn't want a loose mileage to fall off and hurt someone.

would hate to have miliage fall off and hit you while you are trying to catch up to me

 

[subway]

so are the copper washers under the injectors re-usable? is there a recommended place to get them. i found an old thread a while back about making a pop tester out of a bottle jack and got me to thinking. i have half the stuff lying around.......

i would just like to get this fixed as soon as possible because it is costing me allot extra with how much i drive. i went the diesel route for the better miliage, power and reliability. so far not so good

 

[93turbo_animal]

is that only one tank if so you need to run atleast a couple tanks to take out any chance that it was a fluke

 

[SKimballC]

Yeah, you're jumping the gun. Watch it for at least a couple tanks and see how it does. A third of a tank ain't gonna tell you much.
And hey man, keep your newly timed foot out of it.
You didn't mention what kind of mileage you were getting BEFORE the timing job by Mr Moose. That would help for comparisons sake. Mileage on these beasts is a finniky affair, each truck seems to go its own way, and don't forget, low RPM's are crucial for cruising empty and getting good mileage.

 

[Diesel JD]

No, you don't want to reuse the copper washers, they take a seat and then won't seal properly. I will look and see, I might have an extra set I can let you have for the cost of postage. Heck I'd be happy if I could get 16-16.5 on my truck all the time. Is there any chance you guys are getting the new ULSD and/or winter blended fuel in PA?? If so that could account for some fuel mileage loss. I doubt it would take off 3mpg though.

 

[Agnem]

Jred, this was a contingency I was hoping wouldn't crop up, but since it appears to be emerging, I'm afraid it's new pump time for you. Considering the amount we had to turn your pump (the way his pump is laying, reminded me of the infamous Dodge slant six of the 60's ) I feel that your advance ring is worn well beyond normal operational parameters. It is quite possible that it has already become retarded again. I'd recommend you throw a few hundred dollars at it, and renew that fuel system. I'd be glad to help you with it if you want. You can get a good rebuilt pump from Conestoga Diesel over in Lancaster county, or I understand the outfit in Glen Rock on the York County side is good too.

 

[subway]

man i was hoping i wouldent hear that, i am sorry if i was a little confusing in the beginning. the first miliage number was only for the tank partially timed. the other numbers listed are fillup numbers after that. i am on my forth tank and it is looking like it is down in the low teens again.

before i got it timed i was getting around 13-14 down from 16-18 six months or so ago when i first got the truck. aaarrrgghh this isent good timing for me (no pun intended).

maybee i should let it like this for a little to try running bio. i would hate to somehow ruin a new system by accident.

 

[subway]

No, you don't want to reuse the copper washers, they take a seat and then won't seal properly. I will look and see, I might have an extra set I can let you have for the cost of postage. Heck I'd be happy if I could get 16-16.5 on my truck all the time. Is there any chance you guys are getting the new ULSD and/or winter blended fuel in PA?? If so that could account for some fuel mileage loss. I doubt it would take off 3mpg though.

let me know i would be interested, as far as i know we have been running the ULSD up here for at least 3-4 months. i had a bunch of my injector caps start to leak when they first switched over. think i could send them a bill for my pump?

 

[FULL FORCE]

Winter diesel fuel,happens every year,mileage goes down after September.

 

[160k87F250]

DieselPro in Glen Rock is where I got my IP for my 87. Good outfit to deal with.
John