BLM are between 108-115 most of the time and the exhaust is black at WOT. I have a question about were to start tuning?
I have datamaster and tunercats.
Should I adjust the VE tables or the MAF calibation to get the BLM closer to 128? I have a datamaster file if someone is willing to look at it but I'm not sure how to go about posting it.

My car seems to drive decent other then the black smoke when I open it up. This is the first time I datalogged it since I put the cam in. I have put about 1500-1800 miles on it since the cam has been in. (about 6-8 weeks)

Car mods LT headers, true duals w bullets, Moroso CAI, CC306, descreened MAF, stock injectors, stock throttle body

 

My % chang to fuel/air ratio vs RPM at WOT table is
5200 -3.1
5600 -7
6000 -7
6400 -7
6800 -7

This is what leads me to beleave the MAF calibration is off. The wires have been cleaned and the calibations are still the factory tables.

 

It's hard to explain in writing, so I hope you can follow this. This technique will get your LT BLM's all to be very close to 128. You adjust your MAF tables to do this.

You need to do a nice long log of closed loop partial throttle driving, and capture as many long term BLM's as you can for all of the different BLM Cells. (mainly 1-16). Now, lets say at idle, your BLM's are average 110 or so. This means that you are running 14% rich most of the time at idle, and the PCM has to always take out 14% at idle. This you know.

Now, find out what your MAF is reading @ idle, probably somewhere between 6-10 AFGS. Find that AFGS in your MAF table (and all the lower AFGS) and lower all of them by 14%. Then, find another BLM that has fairly low AFGS 15-25 AFGS(probably a low rpm cruising BLM). For me, that is cell 5 or 6. Find the BLM for that one and adjust your MAF AFGS for this area just like you did for idle, but only cover the AFGS that this cell covers. You repeat this for as much of the MAF table as you can find in your datalog, based on the long term BLMS that you see. This calibrates your MAF tables to how your MAF is reading. Try to make the areas between MAF transitions relatively smooth.

All of my BLM's are now averaging 128. In some areas, I have 5 BLM split between the left and right bank, but this is normal. The average is still within a point or two of 128.

Dan

 

Are those numbers negative, or are the dashes there for clarification?
Is it
5200= -3.1
5600= -7
6000= -7
6400= -7
6800= -7
or
5200= 3.1
5600= 7
6000= 7
6400= 7
6800= 7

If the car is running perfectly, the stock power enrichment numbers are super rich. Personally, I zeroed out my PE vs RPM table, and also take out close to 5 more in the PE coollant table.

If your PE vs coolant temp numbers haven't been changed, then the numbers you posted look close to where they should be, maybe a little lean.

A/F = ((100-(# in PE vs Coolant Temp)-(# in PE vs RPM))/100)*14.7

Based on the numbers you posted, the target a/f is 13.3 for WOT. A little lean, but not bad. This would need to be verified with a wideband O2 though. What are your O2 mv readings at WOT?

Dan

 

The numbers posted are negative numbers.

The 02 mv are from 860 950 at WOT

 

I've read that many people target 880-890 mv. Higher is richer, lower is leaner. I don't have a wideband to compare mine (910-920mv) A WOT. Mine stay +/- 10mv from 3000-6000 rpm though.

Your number suggest that you might be seeing a decent swing in a/f at WOT rpm's

Dan

 

Well I scaled the maf calibraton tables by .85 and drove the car for a half hour before datalogging it. Now it is about 130 thru most of the cells except the afgs below 30 which are now lean I will raise those area's and log the car again.


Thanks for the help stereomandan.



Well my datamaster trial just ran out. So I'm done until I get it registered.

 

Well I have the BLM's at about 126-128. Thru most of the cells. It was a little lean in one cell. Do I need to do anything to the VE tables or are the factory numbers close enough? I zeroed out the PE vs RPM table and the o2's are running around 880-900 At WOT.

If I don't have to do anything to the VE tables I may get it on a dyno in a week or two for a few pulls with the wideband.

Also a question about timing. Do the majority of people run the max amout of timing that is possible without knock? Or adjust and make a pull on the dyno until numbers peak?

 

There is no need to mess with the VE tables.

Most people run a couple of degrees of timing back from where knock sets in. For me, I'm set at 34-36 degrees @ WOT, and always use 93 octane. On top of that, the mysterious 2-3 extra degrees of timing show up in my datamaster logs, but that's normal.

Dan