terrible fuel mileage

[lukecline]

I already posted this over at tds, but refuse to post over there anymore. Cant take the over moderation, this last go round of events over there pizzed me off...im done with them. Fuel mileage is somewhere in the 12's now, gee i wanted to get my crewcab in the 12's but that was on the strip and not with fuel mileage lol. Truck is still running excellent, you mash the go peddle and next thing you know your at 120+ and still pullin. Anyway here's my post and another from bean...

Ok im not the one that usually bitches about fuel mileage but this thing is killin me. With 1500 or so miles on rebuild i went on a 400 mile rnd trip all hwy, 5 ppl in cab, grill and 3 big loaded coolers in back i got 16.3 mpg driving 80 mph for majority of trip, needless to say i was extremely happy with that. Also at that time i was getting nearly 11 mpg towing what ever i could hook to. Now with a touch over 5k miles on build, im struggling to make 10 mpg towing less than 20k gross and the last 2 fillups have been 90% hwy (cruise set on 75mph) and 10% city all unloaded w/o trailer avgd 13.4 mpg. Truck runs great, no misses, odd smoke, etc... Just changed oil and probably clean the AFE sometime before this weekend. Any ideas on why i dropped 3mpg?

Keep in mind i have about 5200 miles since engine build completion on 6-17-06 and at 3.38/gal fuel mileage is becoming very serious issue.

TIA

luke

also forgot to mention ive been running power service additive in last few tanks.

Beans post:

You got low sulfer fuel out there yet? Just wandering if a change in local fuel could of coincided with your build.

On edit, pump the intake system up with shop air and find if you have any charge leaks, that will kill mileage, the intakes are the most prone to coming loose at the heads, may even still make close the same max boost but cruising boost will fall off. also check upipes.

 

[jvencius]

Do you always get your fuel from the same place? I'm asking 'cuz yesterday morning I filled up at a station I don't normally use and only went ~80 miles on 1/4 tank (cruising at 75-80) but when I topped off at a different station, last night I went ~240 miles on the same 1/4 tank. Perhaps if you always use the same fuel station, they got a bad tanker (or several) of diesel and you're seeing the effects of that lousy fuel?

 

[JOAT]

Double check the wiring at the EOT sensor. If it comes loose, some PCM codes default to a low temp setting that will cause increased fuel consumption, tho you should get a CEL. If the connection has high resistance, you wouldn't get the CEL but you'd definitely lose fuel economy.

 

[lukecline]

Yes i get 90% of my fuel at the same place, they move alot of diesel through there too. ive never had a bad tank of fuel through them.

where's the EOT sensor at?

 

[94f450sd]

the EOT sensor is on the back of the HPOP reservoir on the drivers side of it.

 

[lukecline]

thanks rich!

I'll go check it real quick.

On edit: checked as many wiring harness connections that i could see. EOT looked good, but i had the front VC harness on the driver side was popped out a bit (broke clip awhile back) so i pushed it in all the way, maybe it was making an intermitant connection. Going on roadtrip this weekend so i'll be able to check fm and see if it changes.

luke

 

[highfive]

Luke,

did you get hammered on TDS for the meat spin thing? that was freakin hilarious one I send it to everyone that p*sses me off now.
Barring a ring not seating right since the build(which I would think you would have some odd smoke from that) or an o-ring poppin on an injector I would lean toward a change in fuel also but don't forget the silly stuff like air pressure or a draggin brake/bearing somewhere.

 

[lukecline]

nope, not even a pm about it lmao!


Well i think its odd that i was getting 16+mpg with only 1000-1500 miles on engine, now with almost 6k im getting 12-13mpg. I would think the rings would be much better seated. I guess i'll get the forklift and raise the truck up to check for any extra drag in the wheels/ bearings. Air pressure is 65psi in all tires so i dont think thats the problem. Wouldnt an injector o ring problem also create a smoke issue?

thanks for all the suggestions!

luke

 

[highfive]

How long was the truck sitting during the rebuild? how's your fuel filtration could have dislodged some crap in the tank to plug stuff up?

BTW-you spin me right round LOL JK everyone thinks you are a sick SOB now.

 

[Tbar]

You break a tip off one of those fire hose size injectors Luke................???


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