I have been looking for over an hour for a post regarding fuel curve adj. by locking BLM at 128. Was the VE change .2 or something like that per INT change from 128?? And in wich direction?? I went out and took the readings when locked at 128 but now I cant remember what next. Thanks
Smitty

 

NEW PROBLEM! Just what I need. After locking the BLM value at 128 Iran the car thru the RPM range up to @ 3200 while sitting in the driveway. I recorded the INT values wich were all high. I increased the MAP 30, 25 and 20 VE tables .2 for every point the INT was greater than 128 and burned a new chip. Guess What? Didn't change a thing! Now I'm no rocket scientist but correct me if I'm wrong, something should have changed. I can't figure out what I'm doing wrong. I burn the chip and double check twice!(Quadruple Check?) O2 sensor is new, heck the whole thing is new! Is there anything anyone can think of that would cause this besides an operator's malfunction? Suggestions would be great.
Smitty

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'92 RS 350 Big Mouth TPI 5spd 2.73 lmtd slp Daily Driver with "ISSUES"

 

I just thought of one minor detail ... I didn't unpower the computer when I changed the chip. Correct me if I'm wrong but this shouldnt matter because the BLM was locked at 128. Right? With the BLM locked its not utilizing what it learned anyhow, or so it would seem. Does this sound correct?

 

It may be so far out you will have to make bigger changes than that. When I am lost I make big changes to see what will happen. It then helps to see which way I need to go.



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Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
Cam change:TRW 198/210 ,450/.460 114 LSA
Stock TBI manifolds
'85 IROC Ex.
14.94-92.00 mph
SPDC base and "350" Vortec coming soon!
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

 

Its not a .2 change. Its (INT-128)*.23 So if you INT at 2400 RPM and 40 MAP is 134, then its (134-128)*.23 = 1.38. You need many points on your curve to get it close. I use Diacom and record about 15 min. of data driving around and then translate it to Dbase, open it in excel and then sort the data to figure out what I need to change. There is a description of this procedure by Glenn91GTA under the popular P730 post. Read that and then contact me off the list if you have any further questions.

 

Do a search on P730 and look for Part Throttle Fuel tuning part 1. I presented a way that does NOT lock the BLMs. Glenn then presented a way of locking the BLMs. Mine is a coarse adjustment, Glenn's is a fine adjustment.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
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Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

"Its not a .2 change. Its (INT-128)*.23"

That is basically what I did. (INT-128)*.2 but it did not do a thing.


Do a search on P730 and look for Part Throttle Fuel tuning part 1. I presented a way that does NOT lock the BLMs. Glenn then presented a way of locking the BLMs. Mine is a coarse adjustment, Glenn's is a fine adjustment.

Dont get me wrong, I HAVE been searching and printing and studying and on and on and on. I tried your way first TRAXION and the BLM was all over the place. I would think I had it nailed down, but I would check once more to be sure and I would get totally different readings. That is why I tried locking the BLM at 128, so the **** thing wouldn't move all over the place. Ever try to catch a pig? A shotgun would be verry handy. I am verry humbled by this whole situation, I will start over with the BLM unlocked but suggestions are welcome. Thanks for the continued help!
Smitty

 

If you are just "revving the motor" in neutral, that will do virtually nothing. You need a load on the engine.

Even recording the BLM/INTs in lower gears has a different effect than at a higher gears. That is why we try to use the highest gear possible when deriving our test data with the heaviest load possible.

Lastly, if a car is just sitting there and idling, the ECM may not go into Closed Loop. All of these "tests" should be done on a fully warmed engine while driving with a significant amount of data. There are "transition errors" where the ECM is gives an "initial value" at a particular load/rpm and then settles down to a more realistic reading.

I found the best way to gather information was to take a nice long drive with as much differing driving conditions as possible. This is a case where "more is better".

 

"If you are just "revving the motor" in neutral, that will do virtually nothing."

Yep! Thats it! Thats what I was doing!

I guess I need to do some more reading but I could of swore I read somewhere on here that this practice would be a good starting point just to get idle and the unloaded ranges where they need to be.(shouldnt this method at least correct these ranges?) And yes, I was in closed loop per the scan tool. In my defense, I did drive around for an hour once before while recording, I seperated the info by RPM, then again by MAP, and took averages, did the (xxx\128)*(VE for that RPM and MAP), burned the image and my numbers were still crazy. Thats why I started over with the BLM locked.

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'92 RS 350 Big Mouth TPI 5spd 2.73 lmtd slp Daily Driver with "ISSUES"