Any 1 know.. If looking at the screen while in datamaster you have the long and short term BLMS which side is for the drivers side and passenger side Is the onscreen left= drivers side or odd fire bank fo engine. Ive tried to find info in the help section to no avail.

Also Finally got my BLMs to 129 on both sides at WOT now when i ax th throttle at the finish i get a major split usually 150/137 or something like that and the car dont want to idle very good. I noticed my IAC pos is at 120-130 or so. This usually clears up if a few 1-2 minutes cruisin back to the pits. Any help would be greatly appreciated thanks in advance.

 

first off your IAC counts are to high, you need to shoot for 35to45.
check your TB an dmake sure the bldes are closing all the way. and if its dirty cleans.

and the blms at wot are not what you need to be concerned with. what seeing there is the last blm that the pcm saw before WOT, and it takes that number and mutiplies it into the formula for wot A/F ratio. the blms dont not matter any more once you go into WOT becuase they are ignored.


oh and a list of your mods will help us help you figure this out, paticularly the split blm part.

 

The car is a 95 TA with a 383 11.1 short block
Stock ported heads that flowed 275 w/matched an ported upper
C 306 cam =230/244 @.050 w/1.6 roller rkrs
58mm holly tb and aftermarket mass?? size?? thinkin 75mm
Hooker long tubes w/3-4" collecter4" borla
CSI water pump low mount alternater
EGR blocked

We have had problems with the tb stickin and it gets cleaned all the time, tryin to keep it closed all the way makes it bind up/ hang open a bit causing a split BLM.

I thought the CPU only ignored the O2's at WOT
Cause just before i stage the I look at the screen and i usually have a split BLM like 133/145 or so then when i read the info after I see it changes to 129 when I go WOT.

 

Generally, if the PCM was adding fuel, it will use the Cell 15 BLM's at WOT. If it was cutting fuel, it will indicate "Cell 18" and lock the BLM's at 128.

Bank 1 = drivers side = left side = 1/3/5/7

Bank 2 = passenger side = right side = 2/4/6/8

 

I have a Holley but not installed yet. I have had a guy post me and say that he knotched the......dunnon what the name is one the side to allow the blades to close all the way.

 

Injuneer: You mean before It goes into PE mode correct?

So if it showing lean 130+ BLM's before i go WOT then it will LOCK the BLM's at 128

And if its showing rich 125 - then it will go and USE fuel trim cell 15 BLM's correct?

I hope i'm not confusing this cause it makes sense to me now.

Is there a best way to correct fueling meaning tuning the MAF calibrations or playing with the % to change fuel vs RPM table

Or should i work them both

 

Blms will often split on decel.. thats what i got from his post anyway. it's fine all the way up to the end of the run?.

 

Yes... if it was "adding" fuel (BLM's above 128) before you went into PE mode, it will continue to add fuel in PE mode using Cell 15.

You've got it backwards. A BLM of 128 means the PCM is calculating the required fuel, and based on the O2 sensor feedback, does not need to "add" or "subtract" fuel from the calculations. If it sees it is running lean repeatedly with the standard calculation, and a 128 BLM, it will increase the BLM's above 128 to "add" fuel to the calculation. So, it the PCM has to add fuel to keep it from running lean in closed loop, it continues to "add" fuel in PE mode to protect the engine from running lean at WOT (I think it might not consider it to be "adding" fuel until the BLM's go above 130... somebody who actually runs a stock PCM might wanna help out here).

If the PCM sees that it is overfueling the engine in closed loop, it will start to reduce the BLM's below 128, "subtracting" fuel. But the logic is to play it "safe" when it goes into PE mode, and it stops "subtracting" fuel and uses Cell 18 with the BLM's at 128.