Ok so i have a custom turbo swap with a vulcan intake mani and blow through maf with a precision 50 trim turbo. I have been having a problem with the car breaking up around 5500 rpms and throwing a p0103 maf high code. I cant log it but i have the freeze frame from the code.

throttle: 80%
rpm: 6049
load: 100%
airflow: 351 gr/sec
map: 254 kpa
iat1: 87 degrees
iat2: 110 degrees
ignition timing advance: 9 degrees
short term fuel trim: 0%
long term fuel trim: -18.8%

let me know what you guys think is the problem

 

That should be tuned out.

 

ok so what exactly do you think the problem is with the tune. the crazy fuel trims or maf settings

 

You correct the trims by tuning the maf/map. How much boost you running depending on how you are fueling? What is your IDC above 5k? What is the AFR?

 

Why would the car be calculating a LTFT at full throttle? That's my question.

And your MAP sensor looks maxed out.

 

not really sure like i said i have no hpt. boost is around 22psi but it does the same problem at 18. and when it was dyno'd originally afr was about 11.8 and i dont think i am running out of 60lb injectors plus meth

 

No way at 22 psi it is maxed. The tables in the tune sure, but not the sensor.

Well what did you dyno? 60's may be too small. I am not sure though.

Also the MAF high frequency is an easy fix with HPT. They just need to change the frequency it cel's at.

You need to fix the code so the MAF is taking care of the fueling. When the code pops up I believe it will start fueling from the MAP, and if that is not tuned you may have problems.

 

hey man if you want to give it a shot, i can send you a copy of my tune, it's for a blow through, with 60#s , conservative timing

it is not setup for meth though, so you would need to disable the meth until you get to tune it. give me a day or two to find the tune file, i switched laptops and have no idea where anything was backed up at the moment

 

he said he doesn have hpt.. how is he going to load it?

 

i just read the first post, not the rest of the thread.

first issue for the OP is that you need to get hpt having a turbo'd lsj it's a necessity.

 

I second that. Mainly because the code yoou are throwing is easily fixed and could solve your problem.

 

Ltft are the average over a longer time frame. They help correct the wear of 02 sensors. Thats just what I read somewhere.

And I agree that any highly modded lsj should invest in hptuners. I dont know where I would be with out it.

 

ha yea i have thought about buying hpt especially since my girlfriend has an lnf also which needs a tune. so maybe i can convince her i need to get it. we'll see though. only reason i never bought it is i dont really know enough about tunning

like i said i dont know much about tunning. i doubt i'm maxing out the map sensor as well. all i know is the turbo flows around 48lb/min i think. i see about 46lb/min across the maf regularly so i assume i'm somewhere around 350whp and 380whp with a good tune. and i dont have dyno number from before cause the car was breaking up on the dyno and the tuner said he couldnt figure out why and blamed my boost controller which wasnt the problem cause boost was holding a solid 22psi.

 

you're not actually maxing it out, there's a calculation wrong in the tune somewhere causing it to falsely say it's maxed out

 

yeah get hpt asap. its not hard to learn. i been reading alot lately and learning. should be fun when i get my new set up on and start tunning it. what are ur spark plugs gapped at? what could be part of your breaking up.

 

9 degrees of timing advance??? seriously? that is way too retarded

 

i have tried every gap possible and every spark plug. i had autolites 3923 3922 ngk bkr7e ngk bkr7eix. and tried gaps from .36 to .28. i definately think its a tune issue. if the car thinks the map is maxing out it would run out of fuel causing it to break up correct or no

no idea i didnt do the tunning. i talked to a buddy of mine and he wasnt sure if the low timming might have something to do with it

 

don't stress about it, just go get hptuners and let me know, then i'll send you a copy of my tune to start from. you can spend 500 hours of work trying to resolve this issue, but in the end, it's going to still require you to have hptuners to fix it.

 

The map sensor is maxed at 22.1psi

 

alright thanks a lot man i'll let you know when i get it

oh really so thats why i only see 22.1 through my interceptor. so i might be boosting over that cause i only have an interceptor and stock boost gauge

 

dude get a boost gauge on that ASAP.

 

yea i will i was originally only planning on running 20psi anyway so i figured the stock would be fine. but it does the same thing on 18lbs so i guess i have to get the code to throw on 18 and see what the map says

 

you are getting a MAF code, not a MAP code. it happens on pretty much all turbo LSJ's. you just have to set the MAF Hz fail high and turn off the codes. the issue with the car breaking up is odd though

 

yea thats what i've been told that i need to raise the fail frequency. the code really isnt my concern its why is it breaking up. and when it doesnt miss and pop it just feels like it has zero power

 

Well if the VE is not tuned then when the MAF fails due to high HZ it could feel like it hit a wall(so to speak)? I just got a maf code in my car and the car jerked hard, I looked at my ltfts+stfts and they were in the 20%'s... I have not tuned that high of RPM on E85 yet, so I suspect that is it.

OP I think you need to get a HPT log and see whats going on as a whole. That would help diagnose a little better.

Also the 0% STFT's are a little odd. Your car is going into closed loop right?