Power loss at WOT

[sjl2725]

I run the Spartan 250 all the time. I am a pretty mellow driver, looking for mileage mostly, but on a rare occasion like to put the heel to the steel. I noticed the other day (and several times prior) that once I floor it, it runs badass for a bit, and then has this noticable loss in power for half a second, then usually takes off again. It is defueling? Is the HPFP not feeding it enough? I used to have a Bullydog PMT while I still had the DPF and CAT, and its a similar feeling to when it was Defueling (Bullydog had a message that said "DEFUELING" when it was actually happening)

I was under the impression that the 250 tune didn't have any safety parameters built in. If so, that's OK I guess, but I just want to know if something is F-ed up with the truck.

Should I make a log file or something to see what's happening with fuel commands and hpfp pressure?

[08stroker250]

There are no safety parameters set in to the 250 tune. Is this something you are feeling on top end, or going through the gears?

[sjl2725]

Going through the gears I think. Surely not at top speed. But it doesn't feel like transmission. It definetly feels like I let off the accelerator slightly, then resume. I'd call it a hiccup, or a stutter.

[TripleE44]

Mine does the exact same thing, but only within the first few minutes of being on the road. Once it does it once, it won't do it again till I turn the truck off and start it back up again. Very strange, and I'm only running a smaller street tune from Innovative...

[KTMotoRider1]

Is it just the defuel on the shift? how long does it last? Ive never tried my 250 tune before but ill go try and see if mine does the same thing...

[sjl2725]

Nah, its for sure between shifts. After TripleE44's post, I got to wondering if maybe it was still cold when I was hogging on it. That may have something to do with it.

I drove the Harley today (getting a bit cold for that..) but I think next time I have the truck out, I'm going to set up a log file, crank it up a time or two and see if I can catch a fluxuation in any of the parameters. Maybe that will explain what I'm feeling.

[wontonrunner]

My rcd 485 was doing this as well. It would pull like a raped ape then all of a sudden it would feel like it lost all power, the tranny would shift to top gear and it will keep going. I was told that my tranny was slipping 5th gear because of too much torque and i needed a new tranny. The first time it happend i though I blew up my motor.

It was the easist fix ever....pull the cover off your airbox and try again. Turns out that even with my AFE drop in air filter I was still starving the truck. Even though the filterminder would never move it still wasnt enough air.

Give it a go. I run without my cover on now and it is like driving a whole new truck!!! Turbo spools quicker, and the whistle is pretty bad *** and it sounds like i have a blowoff valve when i let off the throttle now or when the truck shifts and the boost drops.

[TripleE44]

That's an interesting thought, my truck came with an air raid intake, and I always wondered if it was even doing it's job.... Wondering if it's time to clean or just get new intake all together....?

[wontonrunner]

its worth a try. My filter has 10,000kms on it all highway and it still does it...but it was the box not the filter restricting me. Hope you figure it out.