ok, so i just put my longtube headers and high flow cats on my truck. now it is just killing me on gas mileage for some reason. its like dumping fuel hardcore. my friends say when following behind me i blow some smoke out when i get on it, not like thick black like a diesel or anything, just a light shade of black and only a little bit. i think the truck is running way rich, but i dont know how to tell and im not in the best of area to get it tuned yet up and jlp, all i have is my diablo tuner that came with my pulley and stuff. any ideas on what could be goin on? maf sensor goin bad to throw the air fuel out?

 

if u have a tuner it will dump in more fuel under wide open throttle. if there is no DTCs i wouldnt worry about it.

 

I would think that adding the LT headers has changed your O2 sensor location, and that could be part of the problem. The O2's are programmed for a certain time delay from the exhaust port to the sensor, and adding LT's makes the delay longer, which requires adjusting in the tune.
Maybe some one with LT's will chime in here.

 

The only way to accurately tell if you are running rich is with an air/fuel ratio meter.

The addition of long tube headers moves the O2 sensors further from the engine and requires an adjustment in the tune to compensate for the added distance.

You have an excellent tuner less than an hour away from you at woodbine motorsports in Woodbine, MD

 

yea i know bout down there in woodbine, but he said he wont tune with diablo, i have to pay for the sct tuner and then the tunes, with gas prices and bills from just regular cost of living, i dont have 700-1000 bucks to just shell out for stuff like that...how can i adjust for the sensors bein further away?

 

Unfortunately, that is not one of the user adjustable parameters and would require one of the professional tuners with the software to make that adjustment.

You might be able to find a used XCal 2 for sale for a reasonable price on the different forums but however you do it, it will require a professional tuner to make the adjustment.

 

alright, thanks for all the info guys...much appreciated, im probably goin to set something up with jlp to get it all tuned up nice here this winter

 

what if i turn off all the sensors on the truck, my tuner has that option...will that do anything to help in the mean time before i get it tuned?

 

ideas....

 

you cant turn off your front o2 sensors. even if u could.. u shouldn't.

 

mine does that and i have long tubes and high flows. It's more likely the cats then running rich. I have a wide band.

I had sal do some tuning for me. I was data logging and sending him the info and he sent me some adjustments. Everything seems to be dead on . Under load in the lower rpm if i'm pulling up onto the highway, it does bang right down to 11-11.5 if it just starts to hit boost. Just a little quirk that i never got around to having him tweek but under acceleration into boost, i get black smoke. Even when i was running custom dyno tunes by Jim. I wouldn't sweat it too much.

 

awesome, thats the kinda info i was hopin to hear. im plannin on gettin it tuned soon, hopefully with the right tune it will get better mileage than 7-8 mpg, i use to get like 12 before the longtubes, ever since i got them ive had nothin but issues it seems...

 

if your milage is that bad, then something isn't right.

I had quite a bit of problems after putting the long tubes on. Truck wouldn't idle worth spit. Wide band was showing it dropping bottom out lean, then would come back.

I dyno'd to get some numbers and my af dropped off the map at 10. I drove down to JDM and Jim did some magic .

You are probably having the same issues i had.

What year truck and what mods?

 

03 with 55k. 4lb pulley, plugs, cai, upper plentum, single blade throttle body, 160 thermostat, diablo tuner, obx longtubes, pypes high flow cats, flowmaster 50series muffler.