Tuning Problems

[TurboAWDKID]

Oops! i accidently deleted the whole thread! O well, anyways, i have turned my fuel pressure up to 42psi and managed to get rid of most of my knock, only 0-3 counts up to 5k, but i seem to be running rich down low, 3-4.4k. it stutters through those rpms, then pulls really hard. correction: -15 from 1-4.4k, +7 at 5k, +11 from 5.4-7k. my logger showed 2 errors: air temp sensor and barometric pressure sensor. time for a new 2g mas i guess.

 

[Dream On]

What's the question here?

 

[TurboAWDKID]

sry, im not sure where my head was on that one how lean can i go with my correction, assuming i dont get knock at -20, without having bad timing problems (how much is too much)? also, would those errors be causing problems with tuning?

 

[spyderturbo007]

Yes, you need to fix your IAT and Baro sensors first. The MAS uses air mass to determine fuel delivery. Without knowing the barometric pressure and temperature of the air, it can't accurately calulate the mass.

 

[TurboAWDKID]

well, after i reset the ecu, the code went away and hasnt come back. so, im not sure whats going on with that. thanks.

 

[spyderturbo007]

The ECU doesn't throw the codes right away. Every sensor has a different drive cycle that is required before the ECU trips the CEL. Chances are that you haven't satisfied the drive cycle for those sensors yet.

Do you have a logger?

 

[TurboAWDKID]

yes, i have POCKETLogger. thats where i saw the codes. we had a record high of 84 this week, now its snowing and its like 30 outside, so my tuning has come to a hault. so im thinking of going to a GM MAFT setup. any quams with that setup?

 

[Dream On]

MAFT's are harder to tune it seems. I would just get an evo or 2g mas.

 

[TurboAWDKID]

i just put in the gm maf/t i bought and got it running well. i started tuning today, and wow what a difference! 15psi now seems way faster than it did before, plus when i make adj. they actually work (before my 1g mas was messed up). i still hit fuel cut with psi 18 or over. any way to fix this without a FCD program? I was under the impression that 20 psi was possible. either way, changing the mas was what i neededto do.

 

[ChltDSM]

I am pretty sure the GM MAFT has a dip switch you can flip to disable the factory fuel cut. ( basically a built in FCD feature) Read over your instructions, it should be in the initial set up primer.

If your only running 510's I'd leave the FC active unless you have a way to verify your Injector Duty cycles. If you think you are running a little rich or can stand to lean it out a % or 2 that may offset your fuel cut some @ higher boost lvls.. but keep your eye out for knock! Until you get bigger injectors and remove some of that airflow your kinda stuck in that FC cycle. My point is you probably wouldn't have this problem if you were running 550's and wouldn't have to use the FCD feature.

Ever consider a Chip tune?

 

[TurboAWDKID]

thanks, ill look into that. the only thing wrong with what you said is that i have 510's... but i have 550's, its right in my profile. today i did a run from 2nd to 3rd, and hit fuel cut in 3rd, not 2nd. i dont understand that, unless load has something to do with it. i also have a logger and safc II which im using to tune, not tuning with the maft. btw, i hit 92% idc's today at 15 psi, that seems really high for 550's to me. is this normal or no?

 

[ChltDSM]

My bad, i could have swore I read 510's. How much boost? If between 18-20 then yeah 92% IDC sounds poosible w/ 550's. Can you increase fp? I say if you can get some more headroom in your IDC's and are confident your not going to lean out,then go ahead and fkip the swith for the FC disablement.

 

[TurboAWDKID]

well, i kept messing with it, and found out that with the translator settings for 550cc and 3.5" mas (i have the 3"), i actually need to lean things out to get fuel trims at 100%. my lo settings are 1k +13, 2k +4, 2.4k +3, 3k 0, then 3.4k-7k -5. i set my highs to -5 across the board, did a run in 2nd just to see if there was any bucking or anything else, no knock, but up top it cut out around 5.5-6k. not fuel cut, but like i was so rich that the fuel surpressed the spark. there was no bucking or anything, a lot like when your cruising at idle and you turn the car off. ill do some pulls within the next few days and post the results.