Low fuel mileage
 

Ok guys so my truck has turned into a dieselholic:td: here lately it has been drinking diesel like its going out of style:argh:. Ive checked for fuel leaks and have found none the fuel filter has been replaced an air filter has been cleaned also. I just recently pulled the injectors an cleaned them an installed new copper washer an orings on the injectors an also replaced the orings on the connector tubes. What would be causing this thing to drink the fuel??? Also would a boost leak cause a dramatic drop in fuel mileage? Reason Im asking is bc Ive got what seems like a preaty good leak at were the turbo mounts to the exhaust manifold. Thanks for any help or advice:tu:

That leak could cause bad mileage for sure.

Unless your oil level is going up, the connector tube O-Rings are fine.

Ok so I got a new gasket for the turbo to manifold connection and got it installed an everything an there seems to be leaks. Is there anything else that I should look into or go over?

A bad torque converter. My 94 was getting 15-16 @ 60 mph. I replaced injectors, rebuilt the pump. A friend noted that the rpms moved more than he thought in lockup when he tramped on the pedal. we backed the tranny out for a look at the converter. It was discolored and he said a new converter would likely fix it. It did. Mileage on the next tank was 21. Make sure the valves are adjusted, new air filter . I assume it's not smoking and has good compression?

The OPs truck is a 5spd. How many miles are on it? When did you last adjust your valves? Check all the boots for rips/holes and make sure all the boot clamps are tight. :c:

we had a customer that had a cracked manifold. almost didnt see it and really couldnt hear it. check around there and make sure. replaced with a 3 piece and bumped mileage up some for him. also see you have a edge, pull up tps percentage and set cruise, his also had a bad spot in the tps and it was constintly jumping up and down trying to maintain speed but couldnt fix on the spot it needed to so that killed mileage.

The truck just ticked over 200,000 miles and I adjusted the valve lash probably a month or two ago and set them at .06 intake an .16 exhaust iirc. Ive also replaced the tps with one from genos garage an set the voltage to .670, could the voltage be set to high causes fuel loss???

Depends on what the voltage said on it. Should set .02 or less under what it says if I remember right.

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Also did you relearn it after replacing?

Yeah I relearned the apps after install and adjustment. I also redone my valve lash an set it back to .10 and .20. I talked to my uncle an he told me that having them set at .08 an .18 the valves probably wasnt closing all the way which he said would cause the motor to use more fuel. So I figured what the heck its free an all so I readjusted them to cummins specs. So we'll see how it does:tu: Thanks for all the replies an info guys:c:

Well guys I thought I had this mileage problem fixed but turns out I dont:argh: I just put $70 in it Thursday an it put it right above 7/8 of a tank. Well now its setting right below 3/4 of a tank an Ive only put 88 miles on it:scare2:. Does the mileage an fuel usage sound bout right??? It seems to me that it should do better than that. I dont run it hard an Ive got the smarty on the mileage setting. What would be causing this bastard to drink diesel. Im to the point Im tried of it nickeling an diming me to death. I really need help here guys I cant afford to keep putting $80/week in fuel:ouch:

Ok fellas I need some help, info, or something. This truck is literally drinking diesel like Ive never seen it do before. Like my last post I had 7/8 of a tank of fuel and right now it setting right above 3/8 of a tank and I've only went 245 miles:argh: Now is it just me or does that sound really low?? I've checked for fuel leaks found that #6 injector nut was alittle loose so tightened it back up. Other than that no leaks at all. Ive checked the oil level to make sure its not leaking fuel and making more oil, oil level is still the same as it was when I changed it. Could it be possible that my fuel gauge is crapping out on me??? When I first bought the truck the fuel gauge didnt work an it ended up being that the float had literally fell apart an was floating in the tank. Also a guy I work with said it could possibly be that Ive got a failed ring/rings but the truck doesnt seem to blow a crap ton of oil from the breather. It actually has just alittle bit oil residue at the end of the tube. Also when the motor is up to operating temp theres some steam that comes out of the breather tube, its a steady stream of steam its not like its puffing out like a frake train. So I need any kind of info/help that anyone would know of PLEASE help me out. The truck used to get 500 to 600 miles on a tank now Im lucky if I get 350:argh::argh:

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BTW while going down the road I can literally set an watch the fuel hand drop. Like today when I left work it was setting on or just alittle above 3/8 of a tank an I looked at it when I was coming home an it was setting under 3/8 of a tank. I dont live probably 10-12 miles from where I work.

Why dont you fill it up , drive it a day or two, then check the milage? Thats the only way your going to know if you have a problem or not. Until then it seems like your just pissin in the wind.

Yes I realize I would be better off to fill the bastard up but I do not have the money to fill it all the way up. All I wanted to know would cause it to drink fuel. I should not be able to set an watch the fuel drop from 7/8 of a tank all the way down to a 1/2 or alittle below 1/2 of a tank just driving 12-13 miles. Anyways from 7/8 to a full tank of fuel wouldnt make that big of a difference maybe 6-7 gallons more Im not really sure though. I dont mean to sound like an ass but Im sick an tired of putting all of my hard earned money into the tank just to set an see the fuel gauge drop like its just pissing it away

My trucks guage acts like im pissing away my diesel after the first quarter of the tank and then the last quarter LASTS FOREVER!!! it freaked me out but I filled her up and hand callculated and walla 19MPG so im happy.. But can you hear excessive valetrain rattle? if you do maybe you should have Valve Lash done that helps with milage to..

Yeah now see thats something else that gets me. My guage does the same thing as urs Ranchhand. From about full to 1/4 of a tank it drops like crazy, but thing is when its at 1/4 of a tank it seems to take forever to drop any. Do you think it could possibly be the float in the tank fixin to take a crap on me??

Well you might want to save a few dollars to fill it up then. Because until you put a pencil to paper and figure out what kind of milage you are getting your not going to know what kind of problem you could be having. You mightfind out its a fuel gauge and then it might not be. But until then you are asking what someone "thinks" might be wrong with it, and if you start throwing parts at it thats ginna be way more exspensive than filling the truck up.

See thats the thing Mike Ive already throwed parts at it an no difference. Im to the point of selling the pissen thing. It seems like everytime I think Ive got it figured out something goes wrong with it. I replaced the vp thinking that was the problem but it seems like it wasnt an I also replaced the apps.

This is the ONLY way you will know for sure if you have low fuel mileage. Without fill up at the same pump the same way and hand calculating your mileage anything else is a complete wast of time and money. From what I see and my own experience none of the overheads are reliable and neither is watching the fuel gauge drop. Or not. You very well could be in a tizzy over nothing.