I ran of b20 diesel through my truck a couple of months ago. Up unitl that point my overhead matched my hand calc.
Right after running the tank the overhead said 19.5 and hand calc was 16.3

Still that way.

Truck has 130000 miles on it.

Figured one of you might have an idea as to the problem.

I cleaned the IAT/MAP sensor.
I replaced the LP a long time ago with a holley blue.
I usually run an additive in the fuel.

Could my injectors be shot ?

I don't really trust the dodge folks in this part of the country and would like to have an idea what it might be before I let them touch my baby.

 

Nothing.
Winter fuel.

 

Did you change the fuel filter? Running bio tends to clean the crud from the fuel system and the filter catches it. Change the filter and see if it makes a difference.

MikeyB

 

Changed air filter, fuel filter, dumped 1/2 bottle of injector cleaner.

All last winter my overhead was close to my actual.

Have plenty of boost and fuel pressure.

 

My overhead has never been the same as calc. I'm at 68500 mi. Overhead says 20 - 24.0 and calc tells me 18+.
Also, after dumping cleaner in, you will need to replace the filter after that tank. In fact, I replace mine every oil change (6-7500 mi). Before I installed a pusher pump, my truck would start crapping out on me if I didn't change the filter.
Mine is stacked, so it may just me more touchy. Although it did run crappy w/o filter the change, before the toys were added.
I never paid attention to winter fuel being different in CO. I really have no idea if they change it like gasser fuel. I always figure I get to where I'm going in more style and using less fuel than I did in my gasser truck. So I don't worry anymore.
Greg

 

In order to match the overhead, you have to reset it after you fill up. If you never reset the AVERAGE over 130,000 miles, having 500 miles at a lower MPG will not affect the overall average. Its a math thing.

If your average covers only 500 miles, then the next 500 miles will have a large affect. If you have 130,000 miles the next 500 miles could be zero mpg and it wouldn't affect the average.

I hope I'm not making this worse.

 

Sorry, let me clarify that.
I reset it after each fill, I have been doing that for 68k miles and have never had the numbers be the same.
The computer is doing a perfect world average, I assume.
I did notice that the two are closer after I put on a tonneau cover and bombed the truck. The pusher pump helped too.
Hope that's a bit clearer than mud now......
asta

Greg

 

May have found problem.
Temperature got up to mid-50's and the overhead was close to what I would expect after resetting it.
Temp dropped to 20's next day and overhead creeped off again.

I think it is the IAT/MAP sensor on the manifold. Will go to dodge and
buy a new one.

I reset the overhead for every tank.

 

Is there a test procedure for the MAP sensor on these?
I would be interested in the differance between yours, mine and someone that is getting good readings. Maybe test yours before you change it and then with the new one installed.
It would be nice to have some standards to go by..... I would like to trust my overhead #s. Long trips would be a little less hairy to plan.

Greg
PS, does your truck run better with Bio in it? I don't think they sell it here in CO. I had a chance to run it when I was in Kentucky, but was afraid of mixing it w/ regular.

 

Now this just got interesting.
I went to a dodge dealer to get a new IAT/MAP sensor.
The part costs $77 but it is "restricted".
When I asked what that meant I just got a smile and "could mean several things"

Anyone know what "restricted" means ?