I dont understand this???

[SuperDuty99&01]

OK so here's the thing. I have a 99xlt crew cab short box, and a 01 xlt supercab long box. I have outfitted both trucks the same. Diablo sport predator tuners magnaflow Turbo back 4" exhaust, arm bruteforce cold air, Jasper trannys, triple disc converters, and 120hp injectors. My issue is there is a day and night difference in the way these two trucks run. Oh and the have identical axle ratios. The only difference between the two trucks is cab and bed configuration and the crew cab has a smaller fuel tank. Any ideas?

 

[rammertide07]

Different gearing? Tire size? Edit your signature so we know exactly what apples we are comparing. Go to the "User CP" uo top and then "Edit Signature" on the left column".

My dad's 01 F250 will out run my truck (with the chip on stock setting). And his truck has about 50,000 more miles. I suspect it's the different shifting between the F350 and F250 or the gearing.

 

[SuperDuty99&01]

Both trucks have 4.11 gears both have 285-75-16 Cooper ATR 8ply radial both. Are F-250 the crew cab just feels bulkier and doesn't seem the have the same zip. The crew cab has considerable more mileage but I made compression test on both trucks at time of injector swap.

 

[JRJ04]

well, since you said they have the same axle ratios, we can rule that out.

how are all the filters? oil level? fuel pressure?

Someone correct me if im wrong, but im pretty sure the 01's had more ponies out of the factory than the 99's did.

is the 01 the one thats running faster?

 

[dpantazis]

in 99.5 they changed a bunch of stuff on the motor. turbo and intakes come to mind

i would also look at the tuner. if its the same program for both trucks, its not optimal because of those model year differences.

 

[SuperDuty99&01]

Yep the 01 long bed supercab has a lot more snap to it. Fuel and oil pressure are the same.I swap all filters and change oil ever 3500 miles due to extended idle while waiting to be unloaded.

 

[SuperDuty99&01]

The 99 crewcab also falls in the after changes build date

 

[BIG JOE]

There are different programming (flashes) in the PCM's , from Build dates to Build dates.

Sounds like one truck could be responding differently, than the other, to the Diablo's ?

Also.. Try replaceing the fuel pump inlet fitting on the 99, with a piece of fuel hose, w/two band clamps. (air in the fuel issues).

Joe

 

[SuperDuty99&01]

OK I will have to check the fuel inlet. I have even went as far as to swap pcm,s between trucks.

 

[SuperDuty99&01]

Could this be a weight difference issue? I have yet to scale the 99 but for some odd reasony 01srw supercab. Long bed weighs 300 more pounds than my aunts dew of same trim.Just thinking maybe full crew cab with short bed could be heavier.