ISX fuel pressure control harness

I purchased a power harness of ebay a week ago and put it on my truck yesterday. I was very happy with the results. First off, I have a 2005 volvo vnl with a 450 hp cummins isx. Have not been very happy with the stock power on this truck. Been researching different alternatives to increase power for a while. I seen this harness on ebay for 160.00 claiming to increase power and mpgs. For that price, a guy cant go wrong right? Anyways, put this thing on my truck and cranked it up. I couldnt beleive the results... Climbing hills with a 75000 pounds gross at 68 mph and not loosing any speed. I felt like a super trucker (just kidding). At the end of my 600 mile run. I ended up getting an 7.2mpg average compared to running 65 mph with the same weight, without the harness, and only getting a 6mpg average. I would highly recommend this mod compared to buying one of those expensive power boxes that leave imprints on your ecm and do the same thing. Only bad thing about this harness is the idle. Does NOT idle well with the harness on, but, all you got to do is turn the dang thing off and idles fine. I love it so far, and hope this helps.....

 

Hi I was wondering how its going

 

So far, have not had any issues but, found that the mpgs was not as good as I though they were thanks to trusting my onboard ecm. I tracked the mpgs the good old fashioned way and found that it was 6.3mpg average and not the 7.2 I quoted earlier. Now I only use the extra power on heavy loads and helps on the hills here in Kansas. Thanks for the input...

 

Its an old thread but was wondering how it looks nowadays, does this :

CUMMINS ISX ADJUSTABLE FUEL PRESSURE SENSOR harness we can find on ebay

really works and increases HP and fuel mileage?

I have non egr isx 400HP with slow rears and am already averaging 6.5 city up to 7.8 mpg highway PA/NJ going up to 65 mph.. would mpg's get any better? does this harness work at all?