Just as it says guys. I'm sure this is a stupid question to some of you. I know its the Power Enrichment tables. I have Tunercat and there is nothing labled PE. I am assuming however they are the VE tables and the % change to A/F ratio tables. If this is true what are the #'s in the table itself. For example in the VE table RPM vs MAP, at 6000 RPM with a MAP value of 100 the cell reads 92.2, what does the 92.2 equate to? Fuel? If so. If I make that value say 95, would that add more fuel. or am I all jacked up. Basically I need to richen up my car on the top end because its running way to lean. I hope this makes sence to someone, and If it does can you help me out. Thanks alot, and yes I did a search but didn't find wht I was looking for, hence the new post. Happy hunting.

 

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92.2 means your engine is running at 92.2% volumetric efficiency at that RPM/MAP. If you increase that number, you will make the fuel mixture richer because the PCM will believe the engine is more efficient at that RPM/MAP.

So called "PE tables" are % change to Fuel/Air Ratio Vs. RPM at WOT and % change to Fuel/Air Ratio Vs. Coolant Temp at WOT.

I've read if you are tuning for WOT only, in general, you should leave the VE tables alone, and adjust the % change to Fuel/Air Ratio Vs. RPM table to get your fuel mixture correct. When I dyno-tuned my '94 Impala I only played with the % change to Fuel/Air Ratio Vs. RPM table, and did so until the AFR was correct at WOT.

 

The VE tables are used as a transition between values in the MAF calibration tables. The only way you are going to make any changes to a/f by messing with the VE tables, is to run the car in Speed Density mode. Otherwise, just use the PE tables to make WOT adjustments. Some people zero out the % change to a/f vs. coolant temp at WOT table and just use the other table to get the a/f correct at WOT.

 

While the above information is not relevant to the original question, I want to note for future readers of this thread that it is presenting as fact something that is highly questionable.

I've read just about everything that's available about the use of SD tables in MAF mode over the last ~3 years, and I have never seen input from someone who actually has seen the code and thus knows for a fact when the SD tables are used.

Some people have effected changes to AFR by changing only VE table on a MAF car. Other people have found that changing VE tables had no effect.

Sweetred95ta, I know from your posts that you have only been tuning for a short time, so I seriously doubt that you have personal knowledge that the statement you made is fact.

If you have in fact disassembled the code and can show us definitively when the SD tables are used, please do so - that would be a huge contribution.

Otherwise, please don't present incomplete and secondhand information as if it was fact. It's hard enough to find good tuning information as it is.

 

For one, I know it wasn't relevant, but he did bring up the VE tables in his original post. I am a beginning tuner and have not had much experience in this particular subject. I have, however, read many documents myself and came to the conclusion that this was the only viable use the VE tables could have. The only other thing that I have seen is that they are just there in case the MAF sensor (or circuit) fails or if you need to run the car in SD mode (for whatever reason). The latter of the two wouldn't explain why some people were able to make a/f changes by adjusting the VE tables though. Either way you go about it, they're just theories. No one has a for sure answer. I apologize, and I should have posted that this was the theory that I have chosen to accept as true. I'm not trying to present incomplete or false information. When you tune, do you put the car in SD mode and use VEMaster to get the VE tables in check BEFORE you make adjustments to the MAF Calibration Tables? I do, because I believe that they need to be in check, just to make sure (in case the theory that I believe is true). I would recommend doing this no matter what, because no one can prove that VE table usage is incorrect. If he did searches, he'd be able to come to his own conclusion, but presenting mine is not going to harm anything. Plus, there most likely would be no break through at all if someone did figure out why the VE tables are there. It would be neat information to know, but I surely wouldn't change my method of tuning. We all know their basic function or what we can do with them. Like I said, I apologize if I mislead the OP. I'll retract my previous statement for not being truthful and full of cold hard facts, and I'll keep my theories to myself. Also, there is no need to be dickish about it. You know that I didn't disassemble the code. All you had to do was say that I presented something that was questionable. You then could have expanded, or I would have came in and done it.

 

I think the VE table calibration is super crucial at idle, cruise and deceleration throttle positions because the MAF isn't going to pick up much airflow. I have spent a lot of time over the last week fine-tuning my VE tables to get rid of a stumble at cruise with some positive effect. But at part throttle it is fine, I suspect because corrections via the MAF can be much more accurate.