I replaced my vp-44 a couple years ago, and had my ecm rebuilt .Since then my mileage has dropped over 2 M.P.G. ,I had never had my ecm reflashed until last month. I was hopping my mileage would improve but it didn't. I don't have any issues with starting or the way it runs. I was thinking about getting a Edge Comp box.I already have a  B.D. pump cover with the tap wire, but never did get  a performance box. Here's my mileage # city now 12.5   M.P.G.  highway 16.8 M.P.G.. Previously I got 14.5 M.P.G. city and over 20 on the highway .I've got 20# of boost at wide open throttle and no  or very little black smoke  . Exhaust temps never get above 1200 deg. I  was considering getting a Edge comp to improve my mileage and even though diesel prices are way down. Mike seems to swear by his. Do you think a Edge comp would improve my milage?

                                                                 

 

While the edge will help with mpg I would source the root of the issue first.  

 

Something had to change.    Have you read codes? Tested for boost leaks?  different tires?  lift?  anything different?  

 

I don't see any fueling mods, if that is truck I would think 1200*f would be pretty high for a stock truck.  I don't think mine ever ran above 1000-maybe 1100 back when it was stock.  I would look for boost leaks

11 minutes ago, Me78569 said:

I don't see any fueling mods, if that is truck I would think 1200*f would be pretty high for a stock truck.

Actually, a fully stock truck can reach over 1,400*F. That was my first shocker towing here in Idaho with my brand new DiPricol gauges back in 2004. No other mods.

No codes .I haven't checked for boost leaks, My exhaust temps normally are 800- 1000 deg ., unless I 'm pulling hard on steep hills and than I back off right away, what I meant was that I never let them go any higher.I Just got the parts to build a boost leak teste" let you know if I find any.

1400*f?  really?  wow my truck struggled to top 900*

 

yea I would start with boost leaks and go from there.

I would say there is something different going on. In stock form I was getting 19mpg highway and over 20mpg with the comp and other upgrades. If your mileage is down since replacing parts, something is off. I've heard of guys running the stock lift pump and getting good mileage and then put a fass or airdog on and have the mpgs fall off. 

8 hours ago, Mopar1973Man said:

8 hours ago, Me78569 said:

8 hours ago, hodag56 said:

8 hours ago, Mopar1973Man said:

Actually, a fully stock truck can reach over 1,400*F. That was my first shocker towing here in Idaho with my brand new DiPricol gauges back in 2004. No other mods.

No codes .I haven't checked for boost leaks, My exhaust temps normally are 800- 1000 deg ., unless I 'm pulling hard on steep hills and than I back off right away, what I meant was that I never let them go any higher.I Just got the parts to build a boost leak teste" let you know if I find any.

 

8 hours ago, hodag56 said:

No codes .I haven't checked for boost leaks, My exhaust temps normally are 800- 1000 deg ., unless I 'm pulling hard on steep hills and than I back off right away, what I meant was that I never let them go any higher.I Just got the parts to build a boost leak teste" let you know if I find any.

1400*f?  really?  wow my truck struggled to top 900*

 

yea I would start with boost leaks and go from there.

Actually, a fully stock truck can reach over 1,400*F. That was my first shocker towing here in Idaho with my brand new DiPricol gauges back in 2004. No other mods.

 

Just did a boost test .found 2 small leaks 1 on outlet of turbo and 1 on intake horn boot.very small leaks,just need  to tighten the clamps just a bit to stopthem.I don' really think those little leaks would cause 2 mpg difference ,but I guess I'll find out  .Thanks for all the suggestion. This truck runs better now than it did when it was new, but I've only got 90k on it, just doesn't get the mileage it used to.

Edited March 26, 20169 yr by hodag56

7 hours ago, CTcummins24V said:

I would say there is something different going on. In stock form I was getting 19mpg highway and over 20mpg with the comp and other upgrades. If your mileage is down since replacing parts, something is off. I've heard of guys running the stock lift pump and getting good mileage and then put a fass or airdog on and have the mpgs fall off. 

 

Hmm what was the reasoning for loosing MPGs after upgrades like those?

16 hours ago, CTcummins24V said:

I've heard of guys running the stock lift pump and getting good mileage and then put a fass or airdog on and have the mpgs fall off. 

 

This is most likely because of suction leaks. If the air bubbles are too plentiful the air bubbles can pass through the filter still and be fed to the engine. Air in the fuel will retard injection timing. Airdog's are known for this problem and testing solution is to use thick axle grease on all the suction fittings when hooking up the quick connects. If the MPG comes back you know you need to convert back to Parker Push-Loc fittings.

Edited March 26, 20169 yr by Mopar1973Man

1 hour ago, Mopar1973Man said:

 

This is most likely because of suction leaks. If the air bubbles are too plentiful the air bubbles can pass through the filter still and be fed to the engine. Air in the fuel will retard injection timing. Airdog's are known for this problem and testing solution is to use thick axle grease on all the suction fittings when hooking up the quick connects. If the MPG comes back you know you need to convert back to Parker Push-Loc fittings.

Any way to test for small suction leaks on fuel supply, like if there is no visable leakage by looking at them? 

Just wondering becouse I've lost about 2 mpg lately but just passed it off as the quality of diesel fuel and winter blend fuel.

usualy in the summer I used to get 19 on the highway but last summer I had to baby the truck just to see 17.5. With this fuel were getting now I'm lucky to see 16 mpg

11 hours ago, 01cummins4ever said:

Any way to test for small suction leaks on fuel supply, like if there is no visable leakage by looking at them? 

 

Run the truck. Quick after shutting down pressurize the fuel tank. If there is any leaks a second person should find a wet spot then with the air pressure.

On ‎3‎/‎25‎/‎2016 at 0:39 PM, Mopar1973Man said:

13 hours ago, Mopar1973Man said:

 

This is most likely because of suction leaks. If the air bubbles are too plentiful the air bubbles can pass through the filter still and be fed to the engine. Air in the fuel will retard injection timing. Airdog's are known for this problem and testing solution is to use thick axle grease on all the suction fittings when hooking up the quick connects. If the MPG comes back you know you need to convert back to Parker Push-Loc fittings.

Actually, a fully stock truck can reach over 1,400*F. That was my first shocker towing here in Idaho with my brand new DiPricol gauges back in 2004. No other mods.

 

On ‎3‎/‎25‎/‎2016 at 0:45 PM, Me78569 said:

1400*f?  really?  wow my truck struggled to top 900*

 

yea I would start with boost leaks and go from there.

I have all push-loc or JIC fittings on my fuel lines, all way to VP-44 thru the stock  filter canister. Basically it's the ..same as yours Mike only my gauge line is a 3 ft. piece of1/4 in .s.s. aircraft hydralic line.

If he was getting any suction leaks there would be less fuel pressure. Hodag have you seen that? If so a bucket test could point you in the right direction to start looking for leaks.

I'm  sure I don't have any fuel leaks, but I'll do that air test again, I did it 6 months ago, cause

I had a leak on top of tank and used that air test to find it,  It was the gasket on the tank modual  and I fixed it.

My truck fires the first time I turn the key.  Fuel pressure comes up to 19 # immediately It is parked in a

garage with a epoxy coated floor if there were leaks I would have seen them.I'll keep playing with this MPG problem.Thanks for you guys and you suggestion.

OK if you're seeing solid pressures then I would personally rule a fuel leak out.

 

I think the hardest part with this being an MPG drop is you have to fix or tweak on thing, then drive for a bit and see if the MPGs are better/worse/same and go from there. Definitely not something you can just fix and see the immediate effects of it.

 

Anyways, hope you start getting better MPGs and let us know what you find out!

Will do.