MPG Dropped Since Accident??? HELP!!

[Papa Rick]

My avg prior to accident was 5.2, and since the accident it has been 4.4. I changed the Air Filters, and noticed a slight change, but not like it used to be, and the pyrometer shows alot hotter than it prior to accident.

It use to run 10 on a steep climb, but now a smaller climb it goes up to 10 alot quicker.

My water temp is the same, but the drop in mpg is eating my profits up quick. I still get fuel at the same 2 places as before; have checked my fuel filters and no water or trash in them.

I did get new rubber all the way around, but it shouldn't drop it that much, same tread design as before.

Any suggestions or advice would be greatly appreciated.

[Dejanh]

5.2.... :shock:



WOW !!!

[dieselmanic]

did the accident damage the front end? this sounds like a classic charge cooler leak. lack of turbo pressure and no change in fueling will raise combustion temps. also lack of power and mileage. have the charge cooler system pressure tested from turbo to inlet manifold. this will at least eliminate one possible cause of trouble. :wink:

[Papa Rick]

Just talked to the KW Dealership in Chatt TN, and told them what it was doing, and they said it sounded like the Charge Air Cooler and it wouldn't take much time to check it out.

He asked me what it was doing and I told him what I posted on here, and then he asked me if it was losing boost power and I said yes and he said it sounded like that would be the problem and to bring it by for a pressure test.

This is where I had the truck repaired at from the wreck so if this is the problem, hopefully the other guys insurance will pay for it.

Man I cannot keep paying for diesel at this rate, and with the insurance company not wanting to pay me for my downtime wages it is not easy hanging in there!

[Rev.Vassago]

Man I cannot keep paying for diesel at this rate,

How could you pay for it when you were getting 5.2? :shock:

[Papa Rick]

It has not been easy with the diesel prices going up. In the logging business you don't have a voice as in other aspects of trucking. I have been avg $3.60 per mile but it is only one way so it is really $1.80 per mile.

At 5.2 mpg, it came out ok, but at the rate it is now, man it won't last long that is for sure.

[Walking Eagle]

Charge air cooler but also have them check all other hoses and connections on the HP side

[NotSteve]

What is a charge air cooler, where is it, what is it for and why would it effect MPG?

[usedup]

Charge Air Cooler......(CAC)
What....Lowers air temp after passing through the turbocharger before entering engine.
Where...Usually sandwiched with your radiator and looks like a radiator.
What for...cools air for more density and prevent overheating.
If it leaks...Low boost pressure under load causing high fuel useage.
plugged...High fuel ratio and high combustion temp.
Hope this helps.

[NotSteve]

Yup, that did the trick! Thank you!

[Doghouse]

Steve did you have yours replaced, cleaned or at least tested for leaks when they did your radiator?

[NotSteve]

Steve did you have yours replaced, cleaned or at least tested for leaks when they did your radiator?

They replaced it. When I asked to have it replaced they said it was already in the price they quoted me. They said it would be dumb not to. I should have asked what the hell it was for.

[Papa Rick]

Took it to the KW Dealership in Chatt TN, and they put the air pressure to it and found no leaks, checked the front and back of the turbo no problem.

From there I went to Southeast Diesel and the put it on the Dyno Diagnostic Test and checked fuel pressure holding good, turbo psi good, pwr hp good, rail psi good.

393 hp to the ground
29 PSI of Boost
88 PSI Of Fuel

They could find nothing wrong and no Boost Leak.

Neither place could find anything and were left with me and them scratching our heads.

KW Dealership told me to run it a couple of weeks and if the mpg does not return, then bring it back.

When I first bought the Truck it did this, and I bought locking fuel caps and it came back up, but am not sure if it was something on the Truck now. That was back in Oct of 07.

Any suggestions anyone???

[allan5oh]

New tread will account for some, tires need 50,000 miles of break in.

[Papa Rick]

I would agree that it will cost some on mpg, but never heard of it doing this much damage.

Heck I figured it up and for the past 2 weeks it has cost me $700.00 more in fuel??????

ANY SUGGESTIONS ANYONE????

[Orangetxguy]

Silly question I know...BUT...Did they check out your ECM and make sure the accident did not cause damage there? Did they run the rack??

[Papa Rick]

They told me the ecm was fine, and I wanted them to run the overhead, but after the dyno test they told me this wouldn't help any since it was showing everything doing fine.

[Orangetxguy]

Ok...how about the alignment? Is the truck pulling left or right hard?? Are the drivers tracking properly?

[dieselmanic]

In your original post you stated the pyro was reading differently. since the charge cooler passed the pressure test, something else is amiss. Is the exhaust system free from kinks or obstruction? or maybe an injector is misfiring (bad spray pattern) under cruise conditions. things like this are hard to diagnose but worth the effort. :wink:

[dieselmanic]

another item to check would be fuel injector timing. the injector timing solenoid on my isx stuck in full retard mode causing poor fuel mileage and excessive smoke from the stacks. :idea: