Cammed ls1/t56: sudden lean and high idle conditions
03-26-2013, 08:52 AM
#1
Cammed ls1/t56: sudden lean and high idle conditions Car was checked for vacuum leaks with no luck but I haven't ruled it out completely.
I was not the one who tuned it, so I don't know what the LTFTs were like before, but they look horrible now (+6-9% for idle and lots of cruise conditions). The car idles a couple hundred RPM over desired at a stop and once in gear will cruise control at 1500rpm.
When the clutch is engaged while rolling it drops idle quick (but not severe) then the idle rebounds and hangs at 1500 rpm. Car ran fine a few days ago (even though I think it would be better with a more thorough tune).
MAF sensor has been cleaned, O2s are switching, no codes. MAP is working.
I'm having a hard time diagnosing based on logs because the car was tuned by someone hacking the IFR table and using a stock MAF and VE table.
Aside from a more thorough check for vacuum leaks, are there any other common problems that would make this condition appear suddenly? We did have a weather temp drop from 40-50s to 20s-30s.
I was not the one who tuned it, so I don't know what the LTFTs were like before, but they look horrible now (+6-9% for idle and lots of cruise conditions). The car idles a couple hundred RPM over desired at a stop and once in gear will cruise control at 1500rpm.
When the clutch is engaged while rolling it drops idle quick (but not severe) then the idle rebounds and hangs at 1500 rpm. Car ran fine a few days ago (even though I think it would be better with a more thorough tune).
MAF sensor has been cleaned, O2s are switching, no codes. MAP is working.
I'm having a hard time diagnosing based on logs because the car was tuned by someone hacking the IFR table and using a stock MAF and VE table.
Aside from a more thorough check for vacuum leaks, are there any other common problems that would make this condition appear suddenly? We did have a weather temp drop from 40-50s to 20s-30s.
03-26-2013, 03:21 PM
#2
UPDATE
The IAC was replaced within the last year but a new one was put in just to be sure and the car is now working perfectly.
Car can now be scanned to see if the lean condition was related or just the way the previous tuner let it leave his shop.
The IAC was working when I scanned it yesterday...apparently just not hitting the numbers the car wanted.
The IAC was replaced within the last year but a new one was put in just to be sure and the car is now working perfectly.
Car can now be scanned to see if the lean condition was related or just the way the previous tuner let it leave his shop.
The IAC was working when I scanned it yesterday...apparently just not hitting the numbers the car wanted.
Last edited by thunderstruck507; 03-26-2013 at 03:50 PM.
