ok .. ive looked around and it looks like the only way to tune the ve table on my 91 camaro is to datalog with tunerpro rt .. then slowly go threw frame by frame and calculate new ve's .. now i read in the stickies that the method one of yall use is to get the datalogged blm (say 108) .. and divide it by the ideal blm (128) .. then multiply the ve for that certain rpm / map by that number .. (.84375) is there an easier way to tune the ve tables, and if not .. is that the correct technique .. do i need to do anything else beside calculating new #'s .. such as smoothing out the ve table .. or should i just put the new number in then datalog untill i get to 128 blm's right now ive noticed im sitting at 108 blm's and a 120-130 on the INT .. is this fully rich or what .. some have said that is lean, and some told me that is rich and the computer is trying to pull fuel .. thanks .. adrian

The 108 is rich and the ECM is pulling fuel out. Will need to lower the VE% in those areas. I use the ratio of 128 to the current BLM for this. But not the full correction. I reduce the correction to keep from constantly overshooting.

RBob.

ok .. now im really confused ..

went threw a datalog with 4500 points / logs .. and made my own table in excel of all the ve blocks below 1600rpm ..

then i corrected the .bin file by doing this equation ..

datalog blm value / 128 = X

x * current ve table value = new ve table value ..

i did all this .. then went out to do another datalog .. but this time kept it below 1600 rpm the whole time ..

RAN LIKE JUNK ..and looking at the datalog .. i went backwards .. there all at 108 except one block at 900rpm ..

any ideas what might be going on ..

im using tunerpro rt and all the o2 sensor does is flick between lean/rich every couple seconds ..

right now im using the stock tune with a 2.5* added to the spark table .. seems to work the best so far ..

thanks

There are two ways to tune that I know of. First is the method most use here using the BLM/INT. What I do is use TPRT to datalog, then convert to CSV, use Excel with auto filter, use custom feature to sort a specific RPM vs MAP. Then I use a chart I made to multiply the old VE to get the new VE, plug in new value to table. After I have made all changes, I will "Smooth" the table with a .9 on TPRT, emulate new bin, test drive, datalog...go back to step 1.

BLM=Long Term Fuel Trim; INT=Short Term Fuel Trim. The BLM/INT relationship is as such: say BLM is 108, INT is 96. The BLM says you're rich for that particular cell. The integrator states rich also and is pulling an additional 32 units of fuel and is pushing your BLM to indicate richer at a fast rate. If your INT read 128, it means the BLM has "locked" in and you need to change your VE value for that particular RPM/MAP exactly by 108. If the INT was reading 126, it means it is only pulling two additional units of fuel out and is affecting the BLM at a very slow rate. As the INT moves from 128, either direction, the more influence (rate of change) it has on the BLM. The same is true for Lean. The INT will change the BLM value, rate depends on how far from 128 INT is and if it stays in the affected cell long enough.


The other method is locking the BLM's to 128 and using the INT to adjust, a little easier to decipher. I prefer that method, after I have the BLM's close, like 120-136 range. Do a search for that method. PM me if you want to use some of my tuning charts, they'll help.

ok .. today i did a little searching and found a few "vortec spark tables" that other thirdgen.org users were using on their cars ..

burned a couple chips real quick and took my laptop to see which idled better, cruised better, wot, etc ..

put the first one in .. and idled at 50 kpa (stock tune is 60kpa), but when i start to move (just off idle) it tends to stumble a little ..

then if i stomp it .. its stumbles for a second or two .. then all hell brakes loose and i have no clue what hit me ..

seriously, i only did it twice .. scared the hell out of me b/c the car snapped sideways REALLY quick and was burning the hell out of the tires before i knew what happened ..

and i looked at the laptop afterwards .. no knock was detected, then again im only running around 18-20* in those rpms / kpa's ..

lol .. so i guess i found a sweet spot on that spark table where i get my max power .. and if that isnt max power at that point then im gonna be on happy person when i get this car tuned all the way ..

neways ..

did a little datalogging and it looks a bit better than stock tune .. the timing is alot less than the stock tune .. but now my blms are getting away from 108 with the new table .. some are exactly on 128 around 1400rpm / 70kpa ..

i made a table on excel and noticed a "V" pattern when i put the values that werent 108 .. im assuming that is the acceleration / decelerationg paths i took ..

for my 108 blm's .. should i keep taking out fuel .. or do a little tweaking to the spark table first .. i just found it on a post here ..

also ..what causes a stumble on acceleration before around 2400 rpm ..

thanks ..

adrian

adjusted the ve tables with the datalog ..

again .. now its WAY worse .. not even driveable in open loop .. is it b/c my spark value's are wrong for those rpm's ..

any ideas?

starting to get frustrated .. spent almost a week on this, and havent gotten anywhere except my top end likes less spark advance ..

Before you go too much longer with this problem, do you have the correct reach spark plugs for the Vortec heads. They take an extended reach plug, longer than the normal SBC plugs. R43LTS or equivalent. I am running R42LTS in my Van with 059 305 heads.

i am running summit racing vortec heads ..

when i clicked on the "other parts" thing on their website it recommended .460"

i know for a fact they dont reach into the cylinder, there set back in the hole a little ..

got the accel shorty's right now b/c they clear the hooker headers really nicely .. tried e3's but kept flooding / getting gummed up and barely fit on a couple cylinders...

do i need to go buy a set of longer plugs?

would that explain while almost always (untill around 2400 rpm) the computer reads 108 blm even though i get a lean pop ..

thanks

http://store.summitracing.com/partde...5&autoview=sku

theres the heads i got ..

after thinking about it, it would make sense that i might not be burning all the fuel ..

anyone think this is the problem im having, if so ill go to the parts store after school today and get the correct size plugs ..

thanks,

adrian

ok .. went and picked up some plugs for a 1999 silverado 1500 with the vortec 5.3L ..

got them in ..

and now the open loop is ALOT smoother ..

im really happy right now .. feels more like a car than a lumpy hunk of $hi4 when i drive it now ..

but now i can tell it needs a tune .. so im gonna try and get some datalogging in and make a few adjustments tonight ..

am i correct thinking that i just need to mess with spark / ve right now to get it running decent .. or am i missing something else out that would cause stuff to happen ..

thanks,

adrian


EDIT:

oh, and thanks fast355 for thinking of the spark plugs .. probably would of gone for another week before i even thought of them, and even if i did check them, there showing signs of being lean .. and the computer is showing rich ..

kinda makes sense why i couldnt tune it ..