I have been reading with interest and have a
notebook full of info I have pulled from the web...I have a article by
Traxxion and a coupla 'programming 101' articles from BruceP...been reading
them and referring back...found a thread that told how to adjust your MAF
tables, etc...good stuff...

So armed to the gills I dove in this weekend...started with a sheet that at
steady cruise I recorded BLMs and gms/sec counts...sat down and did my best
hacking the stock tables up...worked out real well...my Block Learns were at
110 or so when I started and now I very seldom see 120...let alone the
1-teens...sweet!!! This was easier than I thought...then I thought...'Bruce
suggests shutting your EGR off while tuning so you don't have several things
to chase'...or something like that...so I shut my EGR off...whammo...my
Block learns at cruise are all in the lower 120s now...My goal is to have
all my BLs around 125-130...hmmmmmm...so now I'm wonderring whether I should
turn it back on and tune with the EGR on...or tune with it off...but then if
I tune with it off...I'll have a lean condition during accels through that
'cruise area' of the MAF tables when I turn it back on and the EGR isn't
flowing...fwiw...my cruise produces 20-30 gms/sec of flow...I have that area
tuned pretty good...but with fluctuations of MAT temps and such...it'll go
rich on me...but during normal cruise and no hot soak time...it's a-ok...any
suggestions on tables to combat this fluctuation of BL numbers when the
motor is seeing super-hot MAT temps?

Idle is still a tad lean and I can't get the tables adjusted so it's a tad
rich...but the values are all in the lower 130s...so I think it's oK...Bruce
says in his papers that if you have a mild cam...you may have issue with the
lower values since the cam is doing funky stuff...but I don't know all the details about
that...lots to learn still...

Then the biggest ?!?!? of the weekend...I raised the %TPS to enable WOT
tables to be able to accel hard and get some figures on my upper airflow
numbers(or so this was my theory) and whammo...I have BLMs in the 130-140
range...I'm scratchin' my head but figure they must be tied to the maf
tables somehow...so I put them back and went about tuning the maf tables.

SOOOO, I am on my way...I still need to tweak my hard accel areas of the
airflow spectrum(my upper non-PE BLs are 122 or so)...it's funny at WOT my
airflow is at 140s...ol 305 isn't maxxing the MAF out...that's for sure

Well, if you've made it this far...you must be really bored...but just
wanted to share...if anyone has any suggestions on a better way to go about
this...let me know...the way I have been getting my Airflow and BLM values
is just driving along and getting the airflow to a certain number and
recording it and the blm numbers...come back, mess with the tables...go back
out...do the same...come back..etc...need a co-pilot though...it's a pain
trying to write, drive, and fiddle with the scanner...thank god for back
country roads...all of this I try to do on flat roads to get an apples for
apples idea of what's goin on.

I have a long way to go...but so far so good...

Thanks for listenning and giving me any helpful hints...

GregF
87 IROC

 

where did you find that thread on tuning MAF tables, I have a good idea but the more info the better.

------------------
355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s.

 

It's a link on this board...just do a search for 'MAF table' and you'll find it...it's toward the top of the list...

GregF
87 IROC

 

If your universally running 130ish your close enough.
What is drivibility like?

You need at this stage measure WOT performance to see what the engine likes. I should have qualifided some of what to disable statments (also remember we were alot more primitive about what and how we were doing).

On some ecms you might find initial tuning to be much easier with the EGR and / or C/L disabled. Some ecms can be making corrections (timing and fuel) when these apply that it's really hard to get anywhere, since the ecm is making corrections, and you wind up chasing things around, without seemingly getting anywhere

 

QUOTE:

If your universally running 130ish your close enough.
What is drivibility like?

You need at this stage measure WOT performance to see what the engine likes. I should have qualifided some of
what to disable statments (also remember we were alot more primitive about what and how we were doing).

On some ecms you might find initial tuning to be much easier with the EGR and / or C/L disabled. Some ecms can
be making corrections (timing and fuel) when these apply that it's really hard to get anywhere, since the ecm is
making corrections, and you wind up chasing things around, without seemingly getting anywhere

REPLY:

What is C/L?

I am universally between 124 and 132 most airflow #'s I'm at 126 to 128...every once in awhile it will skew up to 131 or down to 124...on some blasts where my BLMs are bouncing crazy like after the car is warmed up I will hit the upper teens...but that is only when I let it sit and idle and the temp under the hood starts building...Hmmm, so you think I'm close enough, eh? Wonder if my other ? could be related to my EGR...but EGR shouldn't be in affect if the car is accelerating I don't think.

How is the driveability...awesome!!(I just installed new gears hence the Xtra '!') Although I will admit it seemed better a few days ago...about 5 chip revs back...but that could have just been the cooler weather...or any other number of things...

Thanks for any info.



------------------
GregF
87 IROC

 

C/L is closed loop. I don't have any suggestions about the tuning, but your block learns look great. BTW, I saw a max of 164 grams/second at WOT in 1st and 2nd gears last night, so I hope you're seeing more than that since you don't have a stock cam and I do.

------------------
Greg Westphal
'87 IROC 305TPI/A4

 

Hey guys,
I have a Sunpro scanner and it reads the MAF in a different way (not 100% sure), I think it reads from 0 to 45000 or so. Is there any way to convert to gms/sec?
Thanks, Rick

 

Way a minute!
If you divide 45000 by 255 it equals 176. This seems like the right formula to convert, doesn't it?
If it is, then something's choking my engine and it aint' the MAF (stock heads, that's it).
Rick

------------------
'88 GTA 350 Full of Leprosy (rust)
Full Exhaust, Free mods, Xtreme Energy cam, Intake Pieces and 2100 RPM TQ

13.39@102.50 MPH
1.90 Sec ----- Best 60FT
104.23 MPH -- Best Trap Speed
AIM HIGH!

 

one last thing guys:
128 is perfect A/F
129 and above is lean
127 and below is rich

Am I right or is it the other way around?

 

You're getting it.

Paul

 

A little clarification please...

A 129 means that the actual mixture in the cylinders is lean, and the ECM thus adds more fuel.

or

129 means that the actual mixture is rich and the ECM leans it out to compensate.

Which is it? Thanks

 

Scott,

> 128 means that the cylinders are running lean and the ECM is ADDING fuel by increasing the pulse width of the injectors

< 128 means that the cylinders are running rich and the ECM is SUBTRACTING fuel by decreasing the pulse width of the injectors

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Oh man, this is good. I don't have any of the equipment and I'm already getting very excited about burning my own chips. Just a lot more learning to do.
Rick

 

Actually, for the integrator and block learn function, 128 is ideal A/F ratio, BUT the normal range for both is 128 +- 6. The ECM will not add fuel until the INT value is 135 or higher.

And, the ECM will not take fuel away until the INT value is 121 or lower.

The INT and BLK functions are a measurement from the O2 sensor relating to how much oxygen is in the exhaust gases. A value of 128 is baseline, greater than 134 indicates that there is too much oxygen which means that we are lean, so the ECM responds by adding fuel. The opposite is true for values lower that 122 (too little oxygen, rich condition).

The INT function is short term condition, maybe lasting a few seconds. The BLK function is long term learned memory which is saved in the ECM.




------------------
'87 L98 TPI IROCZ, AFR190 heads, 3.70 gears, ZZ9 cam, 2400 Art Carr TC, SLP 1 3/4" headers, SLP cat-back, no cat, no AC, no MAF screens, Accel manifold base & SuperRam, Edelbrock double roller timing chain, MSD ext coil & distributor, trans cooler, 52mm TB with airfoil, TB coolant bypass, AFPR(58psi), K&N filters, Hotchkis lowering springs, my custom chip, Lay Ind. ram air kit, SS Brakes 1LE upgrade 12" rotors dual piston calipers, 265/45R16 Kumho V700 tires.
ET 13.39sec @ 107.21mph
'90 Eagle Talon AWD, no rust thru 9 winters
'99 Camaro SS, red, 6-spd, T-tops, Mcleod clutch, Pro 5.0 shifter, MAF processor, Direct Flow airlid, K&N filter, next mod: 4.10 rear gears
313.7Hp & 320.6ft-lbf, ET 13.55sec @ 105.1mph

 

Actually, to correct Doc on the INT and BL functions, the block learn number doesn't change until the integrator is more than 5 units different. So, if your BL is 128 and your INT creeps up to 134, then the BL is updated (probably to 129) and the INT goes back down to 128 if the AFR is dead on. If not, then the BL will be updated again if the INT hits 135 (more than 5 units away from 129). I've watched my computer do this enough times to know, plus this 5 number and how things are updated are in the BUA hack.

------------------
Greg Westphal
'87 IROC 305TPI/A4

 

Sweet, that clears up a few questions for me, thanks guys.