mrmint69

I just did a datalog and the right long term fuel trims vs airflow are perfect white on every single cell. Now when I go and check the left there are 20% very lean, 25% just lean and 50% are within ideal mixture with 5% slightly rich. What am I looking for to try and fix this? I checked just last night and have no exhaust leaks what so ever and the track just opened today after 1 year and will only be open for 4 weeks. Injectors are new, valves adjusted correctly & all plugs look the same for both sides.

mrmint69

From doing a search it might be a vacuum leak but with it only doing it on the drivers side what might be the cause of the vacuum leak?

Injuneer

Sounds like you are looking at the graphic presentation from DataMaster. Rather than talk about white cells, just post the left and right long term fuel corrections (BLM's) for as many cells as you possibly can.

mrmint69

Here they are. These are the averages
Cell 1 LBLM 131.0 RBLM 128.1
Cell 2 LBLM 131.3 RBLM 132.7
Cell 3 both at 128
Cell 5 both at 130
Cell 6 both at 128
Cell 7 both at 128
Cell 10 both at 128
Cell 11 LBLM 126.6 RBLM 127.4
Cell 14 both 129
Cell 15 both 128
Cell 16 LBLM 139 RBLM 128.1
Cell 17 LBLM 137 RBLM 128
Cell 18 LBLM 139 RBLM 129.2
Unlisted cells never got hits. There is obiviously a problem on the left.

Injuneer

The only cell with a "problem" is the idle cell (16). The others are basically the same on both sides, and actually look pretty good (less than 4% correction). You have to focus on things that only affect the idle. Check for a vacuum leak on that side, exhaust leak before the O2 sensor, uneven idle air distribution as a function of the blower setup, etc.

Rather than take "averages", simply look at the later frames in the data log. They will have the most fully developed numbers. If the PCM has been reset, in the early frames, the BLM's are all going to be starting out at 128. The engine has to operate in each cell for a period of time before the values stabilize.