I've been doing some logging using datamaster on my 94.. it is running quite rich according to to logs.. if I run the logs and the current bin through VEMaster to alter the VE tables, then use Tunerpro to smooth the tables is it actually doing any good since I'm still using the MAF and not SD mode? I've seen many discussions before on the subject but no clear answer.

 

im not sure either, but it cant hurt

 

That's all you're going to find.

Some people claim they have made dramatic changes in VE tables and it makes no difference at all in MAF mode.

Others say tuning the VE tables has made significant changes when in MAF mode.

 

what I don't quite understand unless the DIY ECM crowd has had it wrong all of this time, the MAF tables are just a calibration for the specific MAF sensor used in the system.. there still must be some other table such as the VE used to calculate fueling given a specific airflow from the MAF with the dynamics of the engines components.. am I making sense here? I just hate to modify the MAF tables unless there is no other way.. VEMaster apperas to be making the correct adjustments to my VE tables but unless something is just that far out of tune it still shows I'm running rich

 

The VE Tables have absolutely no effect on my MAF car. I have experimented with this alot.

If I check the block in my programming for Speed Density then the VE Tables are very effective. Mine is OBD2 though.

 

From what I've read, the VE tables are just helping the MAF tables when they are transitioning from one value to another. The VE tables, IMO, are there for SD operation, which is what I run.

 

from my reading I have come to the same conclusion.. used for quick airflow transitions and open loop unless in SD mode. I still dont understand why when tuning for use with the MAF that we must "lie" to the ecm about the MAFs calibration.. am I wrong in asuming that in theory you could change any aspect of the engine "heads, exhaust, etc" and as long as you used a stock MAF and intake system and MAF calibration the car should run fine for normal driving? apart from tuning idle and WOT where the system is in open loop?

 

Does anyone have a VE table for a supercharged car they can post? I want to go speed density because im running too much boost for both my maf/bypass valve and im upgrading to an atmospheric venting bypass

 

I have had good luck altering the MAF tables to bring my BLM's down to under 128. I think of this as calibrating the MAF to my specific intake setup (K&N FIPK, 1LE elbow, no AIR) as opposed to a viable way to tune AFR. I have seen BLM's go from all over the place to staying within 124-128 after tuning the MAF tables. I think I'm going to play with the VE tables in SD mode next.

 

well I've been tuning my MAF and timing tables past few days and all I can say is wow.. there was alot left on the table from my mail order tune along with better all around drivability.. about the VE tables though.. I ran across a formula somewhere to calculate VE based on known airflow, MAP, and AIT readings..

 

I had some stumbling around 2000 RPM with my tune and I've gotten very close to eliminating them by playing with the VE tables. The fuel trims were WAY off (in some cases 10-12% too rich). By massaging the VE tables, the fuel trims got much closer and the stumbling isn't as bad. I still need to do some work. My point is, they *do* affect the operation of the vehicle, even if you have a MAF.

 

Please list what year pcm you are talking about as well as obd 1 or 2. It is not the same for all cars which is why there is confusion in the first place!

 

This is for my 1994 Impala SS, and it applies to both OBD1 and OBD2 PCMs. My car is capable of running either and I use OBD2 PCM for tuning because i have datalogging software for OBD2. Then I copy the VE tables back to my OBD1 PCM and run them (because OBD1 has the transmission perform feature).

 

I'm searching for an answer on this as well. I figured that I need to get the VE tables in line 1st, then adjust the MAF calibration and PE tables.

To do this do I:
Run it in SD then use VE Master to get to 128, then after getting them in line, switch back to MAF and work on the rest?

 

That is the preferred method of tuning (work out SD mode first, then tune MAF mode).