cormyr

sitting in the garage i tuned so my blms were 126-130 at all rpms, took quite some time to do the maf tables and all, now as im running around town, im rich almost all time. wtf? blms are down around 108-120. what is the cause of this and how do i correct it?

3.8TransAM

If u tuned in the garage and no load on the engine(ie in gear) you barely made a dent in tunign your overall tables.

U need to log the car while driving it and different loads and throrttle openings to properly tune the ecm in its entirety.

Unless I misread or mistaken your post?

later
Jeremy

cormyr

well its maf, not SD so that should not be the case, i'm pretty sure.

cormyr

and the latest update is, i took it out on the highway and lo and behold it was pretty much right on again, like 124-130 blm. so i guess my question is, what would make the blms go really low sometimes and not others? is this normal?

JP86SS

iTrader: (1)

I have an SD setup but I do see 5 to 10 point changes in my BLMs if I get on it hard and the "TV" cable to the trans moves.
Might want to check that out.
On cruising mostly, the trans pressure as adjusted can be seen by additional (or less) loading.

Mangus

It most certainly is the case. BLM cells are broken down by RPM and load (LV8) for a MAF car. Revving your engine in the garage will not load your engine and therefore will not touch the majority of the cells. You need to drive your car in all conditions, logging all the while, so that you can effectively tune your tables.

cormyr

the maf tables simply translate maf volts to afg/s. lv8 is not a variable in that equation. with the $6e mask you dont tune individual cells like you do with sd. there are no such tables for the $6e.

Mangus

Do a little experiment. In your garage, datalog your engine running through the RPM range. Note each cell in the BLM table you hit.

Then go drive your car through the same RPM range. I gaurantee you that you'll hit different BLM cell numbers.

You can't tune a free-revving engine and expect an accurate tune under load. Again, BLM cells are broken down by RPM and LV8.

3.8TransAM

read all of this and then ask questions :-)

https://www.thirdgen.org/techbb2/sho...hreadid=288763

Or u can try the fabulous feature.

We were both trying to help if u cant figure that out I dont know what to tell you.

Have a nice day
Jeremy

RBob

iTrader: (1)

Canister purge will do that.

RBob.

cormyr

3.8TransAM, i've read all those threads and articles several times that pertain to the $6e and many that don't. thats where i've gotten most of my information and that's how i've gotten as far as i have with it. thanks for the concern but i'd appreciate if you weren't condescending.

RBob, that's a very interesting suggestion. You might be right since it hasn't been doing that anymore. Thanks.

D's89IROCZ

I agree ...there is nothing significant one the $6e code. I was all in a panic untill I finall yunderstood the 165 articles pertain mostly to the 32b.

I am curious too cormyr. I have read all the stuff too. I just want to know how to tune the idle ... part throttle ...highway mode ... WOT . The tables are very different .

3.8TransAM

I was doing some research on myself and found my old posts.

My first post on the prom board was 4/16/01 and I'm still asking questions and now donate my time on the board as a mod as well.

My point being, we all start somewhere, when I started and alot of the oldschoolers who were here before me started, they werent multiple choices for hardware and software.

Think Diacom was the biggie for datalogging along with Freescan?

We had GMECM and Tunercat for editing. Most guys had homebuilt programmers or a PPII(or I depending on age)

We had no stickied, no topics hashed out, no Tuning Guides outside of Bruces 101 and smattering of stuff and a ECM GUY's hac's.

I've been here so long, I remember when the prom board here was a closed board and not open to the general public. I made inquiries about it but was never a regualr until the same time it opened up to the public as a reg board here.

We're not trying to beat anyone up or think your smarter/dumber than any of us. It just gets hard when people put down what we say could be an issue or might even be exactly the problem when we are just trying to help. Especially when the advice comes from someone else who has a tremendous amount of experience on the same setup your running(not talking about myself).

It's a long hard and scary learning curve. Ask Bruce about the Christmas eve morning him and I spent 3+ hrs on the phone so he could explain following/reading code enough to me in plain english that I could follow the aujp hac. Or how many times Raucher has explained the same thing to me only to have me look him in the eyes and go" Can u dumb that down one more notch for me" lol.

ok I'm done ranting for now, no one here is trying to make anyones life hard, heck, we're trying to make it easier with things like the "Tuning Guide".

Someone can pick up the $6E and start writing a tuning article for it, provided it is factually correct, I'm more than willing to make it a sticky and/or contribute to it as I have time.

Your on the right track with the scalar tables and pure datalogging.

The canister purge is also a good one, disable it and repeat and see where your blm's are.

Also, disable the egr and retest, could also influence things as well.

since your datalogging, compare good blm with bad blm run and see if you can find something active in one and not the other, could be something else your not catching

later
Jeremy

cormyr

hey it's all good. now back to the matter at hand...

fact is, there really are no $6e articles posted. most of the info i got was from ski_down_it, funstick, grumpy some others who have posted tidbits here and there. the rest i had to extrapolate or figure out myself. based on the available info and my own personal experiences i can say that unlike the 32b mask, $6e has no BPW vs. LV8 table that you can edit yourself, at least not with tunerpro which is what i use. the $6e mask was supposed to be an updated and improved mask for the later maf cars. since there is no BPW vs. LV8 table you can change, are the values changing themselves??? maybe one of you code hackers out there can explain.

ZZ28ZZ

Might wanna check the fuel press while it's running good, then if it goes rich again, re-measure your fuel press.

I used to run $32b, then switched to $6e and a ARAP bin.
My eng seems to like the ARAP a lot better, plus highway mode is nice too.
Adjusting the fuel inj constants and the MAF tables will get you pretty close for steady state running. The PE and AE will probably need tweaking after you get the steady state stuff tweaked in.

cormyr

know what it was? bad fuel pressure regulator. lol. good call zz28zz.

RednGold86Z

iTrader: (1)

In which way did it go bad? Did it tear the diaphragm? Did that cause fuel to enter the vacuum line to the plenum?

Just curious.

cormyr

very slow responding to vacuum, if at all, better reponse to decrease in vac than an increase. the pressure was drifting all over the place, but very slowly. not sure what would cause that.

2new2funny

So, Cormyr, you achieved a satisfactory tune just by revving in your garage, then?

cormyr

i'm glad you asked. the problem i had was a bad afpr. my tune is now dead on...everywhere. sitting in the garage, or driving around. so it appears afg/sec are afg/sec no matter what the load is on the engine since all you are doing is changing the maf calibration. i get a slight amount of fluctuation accelerating and decelerating but it all stays right in the 124-132blm range and its usually 126-130 most of the time. on a $6e you cant tune pw vs lv8 so all you can do is maf tables and that seems to be enough, or at least gm thought so i guess. i will say though that sitting in the garage was only good to a point since i obviously couldn't get up to 255g/sec with no load on the engine. but it was a good starting point at least for basic driveability.

2new2funny

How much were you able to flow?

cormyr

[QUOTE]Originally posted by 2new2funny
How much were you able to flow? [/Q]
well that i will probably never know unless i hookup my intake to a flowmeter because the ecm stops registering after 255g/sec. fear not however, we have power enrichment, which allows for as much flow as the engine/intake will physically flow. just hookup your wbo2 and tune your topend afr to 12.5 - 13 to 1 using pe vs rpm and youre in like flynn. its actually pretty simple once you have a grasp on the basics and about as accurate as you will need. just takes time. guys have been known to run 10's with maf on a naturally aspirated big inch sbc, if thats what you're asking

gta_88_kicks

would an engine under load, at the same rpm as an engine not under load, require more air to keep the same rpm?

what im saying is will a loaded engine show more gm/s of airflow at the same rpm as an unloaded engine.

cormyr

yes. think about it. you close the throttle blades, that creates more of a vacuum, i.e. the engine is sucking against a highly restricted tb, therefore less air per rpm enters the cylinders. open them up, less vacuum, more air molecules enter the intake for the same rpms. its all about air pressure. thats why forced induction kicks so much ***. it compresses more air into the same cylinder volume. the ecu then adds the appropraite amout of fuel. a maf simply measures the approximate number of air molecules entering the intake.

Siggy

I really enjoyed this post and I would like to see a tuning article develop as a sticky, I'm still on the low side of the learning curve but would sure help where I can.

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