lean after intake - what to tune?
08-24-2004 | 01:11 AM
#1
lean after intake - what to tune? I swapped from the ls1 intake manifold to the ls6 manifold yesterday evening. After all was said and done, i started the car up and started logging. Right away, i noticed that my LTFTs were 25+%. If i reset, they would climb right back up. I tried changine my VE table and IFR to see if i could get any change and i wasnt able to.
My car was running pretty clean before the intake swap, i had all the fuel trims slightly negative w/ no KR across the board although i have yet to touch PE. I had used a few spreadsheets from hptuners and the idle how-to from this site.
After reading all the posts, i get that everyone says no tuning is needed after an intake swap. I thought i had an intake leak so i sprayed brake cleaner around it but the idle didnt raise at all. Just to be sure, i pulled it back off, checked all the seals and connections, put it back on and the same thing.
Ive read of a few other having similar issues but no resolutions. Any guidance is appreciated.
BTW mods should be in sig and im using HPTuners
My car was running pretty clean before the intake swap, i had all the fuel trims slightly negative w/ no KR across the board although i have yet to touch PE. I had used a few spreadsheets from hptuners and the idle how-to from this site.
After reading all the posts, i get that everyone says no tuning is needed after an intake swap. I thought i had an intake leak so i sprayed brake cleaner around it but the idle didnt raise at all. Just to be sure, i pulled it back off, checked all the seals and connections, put it back on and the same thing.
Ive read of a few other having similar issues but no resolutions. Any guidance is appreciated.
BTW mods should be in sig and im using HPTuners
08-24-2004 | 06:23 AM
#2
Teching In
Joined: Jul 2004
Posts: 47
Likes: 0
From: Ohio
Sounds like you might have a vacuum leak, check the back on the intake that is where most of them leak.
If you can't change the LTFT by IFR then you have a leak somewhere.
If you can't change the LTFT by IFR then you have a leak somewhere.
Originally Posted by my2kTA
I swapped from the ls1 intake manifold to the ls6 manifold yesterday evening. After all was said and done, i started the car up and started logging. Right away, i noticed that my LTFTs were 25+%. If i reset, they would climb right back up. I tried changine my VE table and IFR to see if i could get any change and i wasnt able to.
My car was running pretty clean before the intake swap, i had all the fuel trims slightly negative w/ no KR across the board although i have yet to touch PE. I had used a few spreadsheets from hptuners and the idle how-to from this site.
After reading all the posts, i get that everyone says no tuning is needed after an intake swap. I thought i had an intake leak so i sprayed brake cleaner around it but the idle didnt raise at all. Just to be sure, i pulled it back off, checked all the seals and connections, put it back on and the same thing.
Ive read of a few other having similar issues but no resolutions. Any guidance is appreciated.
BTW mods should be in sig and im using HPTuners
My car was running pretty clean before the intake swap, i had all the fuel trims slightly negative w/ no KR across the board although i have yet to touch PE. I had used a few spreadsheets from hptuners and the idle how-to from this site.
After reading all the posts, i get that everyone says no tuning is needed after an intake swap. I thought i had an intake leak so i sprayed brake cleaner around it but the idle didnt raise at all. Just to be sure, i pulled it back off, checked all the seals and connections, put it back on and the same thing.
Ive read of a few other having similar issues but no resolutions. Any guidance is appreciated.
BTW mods should be in sig and im using HPTuners
08-24-2004 | 12:46 PM
#5
i removed my egr when i did the headers the new intake doesnt have the provisions for it. ive been logging all my trips and its consistent that as soon as my foot comes off the gas, they ltfts climb. for a vaccuum leak, i would think the same symptoms would be the same across the board since even when the engine is in higher rpm it would just suck more air through the leak
08-24-2004 | 04:06 PM
#6
LTFTs @ +25% means there is an air leak somewhere after the MAF, making the PCM dump max fuel to compensate. The little gasket on the EGR is one culprit, but you don't have that anymore. I had my MAP sensor leak when I changed intakes, and it caused that. Threw a code when it fell out. I assume you've made sure the coolant bypass tube isn't holding the front of the intake up ever so slightly. Mine did....
