a MAF car. Seems like I just can't nail it down. Been playing with the gm/sec vlaues in MAF table 1, just that when I make a change, the BLM goes too far. IE was at 137, made a change...then 122, changed again...now still on the rich side. All around the 6.0gm/sec area.

Read about adjusting the "Injector PW correction vs Batt Volts" table. But does this affect all areas that motor runs in? Adding pulse width should richen up BLMs at all load points?

Maybe with a MAF car it is impossible to get the idle BLM right on. Tonight I looked at a data scan, but car was not really warmed up, and idle BLM was about 134. When car is warm, seems to run around 122.

TIA, Mike

 

Hi.

I am in the same boat as you. I just got into burning few weeks ago so I am new at this. However my idle is showing very close to 128/128. I am having problem with other gps areas.

I think that MAF can be tricky when it comes to correct measurements. I think that different weather conditions could affect the reading as well.

I only collect the data when the car is really warm.

I have been using the % method to adjust MAF tables, how about you?

How do you adjust an area when the BLM is 132 and INT is like 140?

Are you suppose to lock INT?

I am new at this and still learning. But if we share our experiences we should be OK.

 

Hi All,
I too am in the same boat. Having trouble getting idle BLM's down ,Ive been under the impression you should not touch scaler table unless you absolutely have to.?.

 

With all my time tuning mafs using the pw vs batt volts is not the best way(on maf)to cure a lean idle.Thats more for like old or aftermarket injectors.I hear that works great for sd though.I have a friend that tunes grand nationals in missouri.All the custom bins he hacked the maf tables was changed. Check my maf tables topic post on this board.You'll need to change one of the 4 points (counts 0,64,128,192)on your 1st maf table.Check your gr/sec at idle,mine is 7grams.This value should be used in one of these counts.Then smooth counts 0,64,128,192 to the rest of the scale.
The way I do it is get my engine warm.Use the scan tool and read your gr/sec @ idle with trans in park.Then put it in drive but at a stop and check the gr/sec.Put the park gr/sec in count 0 then the drive gr/sec in count 64.In a perfect world this would be it for a lean idle.If your injector contant is far off from your actual inj flow then your counts in the maf tables will be off. Not to mention your iac need set and be in perfect tune.Oh yeah you need to do this on a warmer day with low humidity.Email me if you want direct help.
Before the seniors citizens hassles me,just listen.This has worked for me so I am sharing it.I tried pw corrections a very long time ago.Yes my blms would go to 128 but the int was crazy.I want it perfect so my way gets a rock solid 128.Besides I could'nt find one person on this board that can tell me(in any detail) what the maf tables are,what they do,and how they relate to ve(not ve tables)etc..
Tunercat told me and countless others that the maf tables should not be touched.Unless the maf is modified.This is wrong,I had to change my 1st table to fix my lean idle.Not because I have a modded maf but because my gr/sec is different than stock in many areas.Not to mention the tables needed tweaked here and there after the 30 pounders.Tunercat does have one **** of a job though.

 

Thanks kvu for good points.

That should help some of us with idle problems.

 

Yeah Thanks alot,
Its nice to have someone who actually tries to help..

Just 2 more questions though. after changing the 1st table should i change the others to corospond or just leave them be.

Second question ,I plan to buy new injectors soon especially since my next build i think im going 383- im planning on 30's
are accels ok? are they all pretty good?

 

Wow, lots of responses allready. I been adjusting the gm/sec values by percentages, up or down as a function related to 128. Actually, +- 6 from 128 is still less than 5% change, so maybe those numbers are ok to live with. I only use the BLM numbers, don't worry about the INT, that is a finer adjustment. Haven't used the method of locking the BLM to 128 either.

The MAF tables are not that impsosible to work with, don't let anyone tell you to leave them alone. Just takes time, lots of chips.


My idle had been holding at around 6.0gm/sec when warmed up, so I have been only changing counts 192 and 256. I have left counts 0,64,128 pretty much alone. KVU, I like your method. Sounds like it might work. I am glad to hear you say that the batt volts correction table does not help much with MAF cars. I beleive my injector constant is ok, and the IAC is working fine. I did reset min idle a while ago.

I can't wait to try this method, hopefully others will benefit. But why is the lowest gm/sec in count 64? (in original MAF table 1)

 

This is to be played with if your voltage drops at idle. Unless your alternator is weak or you're idling at near-stock speeds (~500 rpm), then you shouldn't need to mess with this table. You're correct in that if you change it at the voltage your engine runs all the time, then it'll make a global change.

It took me a little time to zero in (or should I say "128 in"?) on the idle BLM, but it can be done. I don't have my BLM start learning until the coolant temp is 140 degrees F, and usually don't even look at it for tuning purposes until the engine is fully warmed up.

To answer DANIELEK's question, you need to make smaller changes to the values if your BLM is 132. However, if your INT was at 140 at the same exact time, then the computer wasn't finished adjusting the BLM yet. You don't need to lock the INT, but you can lock the BLM (set max and min to 128) to really fine-tune things, but I've never found that necessary if you can get all of your BLMs to a range of 126-130, or even 124-132 if you're not too picky.

KVU, the MAF tables don't relate to VE at all. They calibrate the MAF sensor so that it's telling the computer what it's actually reading at each count, which correspond to a certain voltage on a look-up table. The way the MAF works is that it sends the voltage to the ECM, which looks it up (interpolating between counts) on the table, takes that table value, multiplies it by the table scaler and divides by 256 to get the airflow. Since the intake tract before and the dynamics of the intake runners/manifold after the MAF sensor affect the airflow through it (as well as changing the MAF itself like removing the fins or screens), the MAF tables need to be recalibrated for changes to those other parts.

To relate to 87_TA's question, the tables (#1 through 6) are consecutive in the MAF voltage and hence, airflow. Each count in a table is specific to a certain MAF voltage and is not repeated in any of the other tables.

Mike, I don't know why the lowest airflow is not at the lowest count. You'd think that count 0 would be 0 gms/sec...

 

Mike,you should have 0 as the first count,check again.87 ta don't change the other tables for an idle problem.You' will just need to make the 1st 4 counts in the scale blend to the next few counts while leaving the last 2-3 counts in the 1st scale alone(for an idle problem).The accel injectors are a good choice.They are just as good if not better than injectors that cost twice as much.Thanks Greg for explain how the ecm communicates with the maf.I have a 400sbc and have burned hundreds of chips for my car.I'm not saying the maf tables are like a ve table.BUT there is a cause and effect of ve.When I lowered my car 1 1/2 inch my blms went a bit rich.The blms did'nt go far rich but a bit.And changing things like 1:6 rockers the maf tables did require a slight tweeking.As did the accel injectors.The hedders made a change too.I live with my scan tool,laptop,eeproms and pp in my car(no I don't actualy live in my car).I have a platform it all attaches to.It has all the power wires connected to a single inverter.All this sits on the pass seat and pp and such is fixed to the platform.It can easily be removed also,having only one power feed to the car.Ok I admit I don't know how to set up a ecm test bench,know assembly language or much about sd.I am learning about all of that though.I can use tunercat like a motherf*cker though.I have learned so much about maf tpi. I need to build maf a site with a guide and a board,host anyone?Maybe thirdge.org will give me a maf board,yeah right .I really don't want to step on toes in here.Besides I'm not a moderator so I dont want thirdgen getting mad a junior member is giving advice.

 

But if you do use my method you need to drive around for a while after the changes to get a stable reading.You also should look at the integrator when collecting data for changes.This method @ idle got me a solid 128 int ,no flux.

 

Thank both of you guys for the help,
it is appreciated..

 

Thanks to Greg and Kvu. Very *** info guys, keep it coming.

I have another question.

So, if you port your MAF and it is now flowing more air then I should be able to see that extra flow through the BLM being litttle higher, right? (lean condition)

Also guys if my INT is really high or low I should keep the car in the same RPM/Speed for it to stabilize to (128) and once it does look at the BLM and adjust the MAF table accordingly?

Is that the right way?

 

Yep, and I think the effect is bigger at lower airflows, which is probably why the lean idle is seen more than it being lean anywhere else.

Yep, that's the best way to so it. Actually, you'd want to just stabilize the airflow for a few seconds since that's what the MAF tables are based on. The INT can vary +/- 5 from 128 with the BLM stabilized, so once the INT is anywhere between 123 and 133 the BLM won't change any at that particular airflow and RPM.

 

The only time you'll be able to really see changes in blm after a mod is if your ecm tune is perfect,or very close to.search locking blms,Glenn has a clasic explanation on blm and int.

 

This is good reading material, so lets keep it going. Tonight I did a solid 10 minute idle scan record, after my friggin' scan tool finally linked up. I had the hood down, in my garage, air temp about 60, coolant temp was about 180+, and this is what I saw: Idle in park, MAF reading 6.2-6.3; put it in drive holding brake, MAF reading 7.1. BLM around 126, but have seen it lower at idle.

So from what KVU says, 6.2 should go in counts=0 and 7.1 in counts=64? But what about the next few table entries? Just graph out the table and try to extrapolate the points for 128,192,256? Above that shouldn't change. I am going to burn another chip tonight making these changes. I don't usualy burn chips without running the car a bit, and doing some tests. I think I am going to take out highway mode, in order to get some more "learn control" data.

I haven't done any work to my MAF itself, but did major intake base porting, as well as runner and plenum work. I would think this would affect airflow, esp at idle. But actually I don't think I am off too much. However always looking to improve.

Greg, how do hold off learn control until your coolant gets to 140F? Are you using the O2 timers? My alternator is in good shape, and I don't have any killer electrical loads that would really drag down the volts at idle.

 

Ditto to all the above on letting the blms stabilize; also be sure to hold a steady throttle position and load/gps while obtaining readings-if you start to try to tune to the "transitional" changes it'll drive you crazy.
If you want to try locking the blm and then tune to int-get it close first. If you just lock the blm and the int max's out you could be seriously lean.
I've always gotten the blm's close with the inj. constant first; but a while back someone mentioned trying to leave the inj. constant and scale the maf tables first-any info out there on that attempt???

 

As others have stated, this is some awesome info. I have done nothing but Inj constant tweaking with my setup. The MAF tables are 100% ARAP at this point. I really can't wait to get after this. Not that my car doesn't run well, but I still see some room for improvement. But....... must not play with PROM until finals are over..... all brain storage space has been allocated .

 

Since most of my cells are runnig little rich i will try a little different approach and will increase the FI size a little bit and see what happens.

Since my idle BLM's are right at 128 and all other cells at 122, I will have to adjust the MAF tables at low gps to address idle's rich condition.

This is my first time playing with injector constant and will update on what affect it will have those cells.

 

I would imagine there would only one way to zero the maf tables.I have not tried it but it is based on what I have learned.Take count 0 and make a 15% change going rich.See if this noticable change is at idle in park.If the change is higher or lower than idle in park then change the inj constant.You will know the right inj constant when the 15% change is seen in count 0.Once you zero in the counts w/ the inj constant then your ready to tackle the maf tables basically count by count.Speed density uses 5 ways to calculate mass air flow rate.We have direct input from the maf to calcuate mass air flow rate and load.So using leaning the injector constant might be fine for sd.But I do know it is vital to reshape the maf tables if you want things right.Not dramatic changes most of the time.I have gotten the vibe that even tc don't have a firm grasp on the maf tables.Or they don't want to be responsible for dumb sh*ts f*cking up their engines.Did you guys get that lean idle fixed?

 

Sounds about right. Putting the tranny in Drive puts a load on the engine, which sometimes requires more air (and fuel) to keep the engine at a certain rpm. BLM looks really good for idle.

Depends on what you're starting with. I wouldn't mess with count zero since the next count up is only 3.23 gms/second and the next one (count 128) is 4.49 gms/second. I'd start at count 192 and just change that value to see what affect it has in that immediate airflow range.

If you're getting an idle BLM of 126, you're right on target.

I set the BLM minimum update temp to 140 degrees F. The computer goes into closed loop w/in 30 seconds of starting (car stays in garage, and heated O2 sensor helps a lot), but only the INT is being used until the engine is almost warmed up.

 

I'm glad to see we have compiled some usefull info on maf here.Tunercat told me not to touch em.But this will help people out.I just thought there would have been a board "pro" in here sharing info also(besides greg).

 

Don't discount the injector PW vs. voltage. I did some playing around this weekend and checked my BLM vs. voltage for the data I've logged over the past 2 weeks. Guess what, starting at 12.4V (headlights, fans on, radio loud) I was running at an average of 131, and going to 14.4V I averaged 124, with an almost linear slope between them. Didn't matter what RPM (to a point).

I haven't changed the values in the table, but I'm going to do that before I start fiddling with the MAF tables.

The only downside is there isn't much resolution in the table. I mean, it goes up to 25V, but you've got serious problems if your alt is running at 25V. Maybe I'll look at lowering the range on this table, from 11 to 16V to get more resolution.

 

Greg, I haven't seen that parameter "BLM min update temp". Is that in TC's $6E tdf? What version are you upto?

Here is what I did with my MAF table1 recently:

Before: (Going from 0 counts to 512)

5.6,3.5,4.6,6.0,8.2,10.0,12.8,16.3,20.2

Now:

6.2,7.1,7.8,8.6,9.4,10.6,12.8,16.3,20.2

Not sure this was a good idea, but had to try it. At first startup, and short warm up, car would not settle down and idle. It surged between 500-1000. So I took a little drive, and came back. Seemed to idle better. I haven't had a chance to scan yet. I want to drive it some more, then do a scan. I know the ECM needs some time to relearn things after a new PROM. So, did I do a bad thing?

But on the MAF values, all the bins I have seen show that count64 has the lowest gm/sec reading. I had been just messing with counts 192 and 256, to nail down the idle. My idle BLM has been ranging 122 to 131, just cannot get to stay at 128. But with most scan tools, you only get the gm/sec reading, not the number of counts that the ECM sees. So hard to judge what table entry to play with.

KVU, any more tips? Did I do the right thing?

 

Pw vs volts does work but not if you wan't the maf tables right.From what I understand the maf is used to calculate load.So the maf tables need to be correct to have the system working properly.But for what your saying alex,the pw table is what you want.You have given the perfect example of when to change the pw correction vs batt volts table.But A generally lean idle needs the maf table adjusted,I have found.

 

I would first make sure your inj contant and fuel pressure is fixed before tuning the maf tables.I did state to move only one cell count from stock to 10-15% rich to see wich count shows the change @ idle (O,64,128,192 usually represents idle.So mike don't go crazy doing too much at once.But the thing is to find the count that effects idle,in park.Once you know that count then you'll just need to change that value a little at a time until 128 is achieved.Then find the count"s" that effect idle in drive and use the same method.Do that and get back to me with some scans.

 

Oh man, this post is growing fast. Good info guys.

I have few questions though.

- How does the ECM use the Spark Correction LV8 vs Coolant Temp table. In my bin the Collant Temp Spark Correction is diable at -40F. Is this normal?

- Closed Loop Rich/Lean Threshold vs Airflow- what does this table do?

- A/E factor vs Change in LV8?- how is this table used?

- A/E Decay factor vs Collant- how about this table?

I know that some peolpe know the answer so please share.

Thanks.

 

Read Bruce Plecan's programming 101 on the ecmguy site.The tables are for speed density but maf has same or similar names.That will give you an idea of what the tables do.No need to mess with all the tables in tc/winbin at this point though.

 

TunerCat, what's that? This parameter is only in the latest .ecu file for WinBin.

You went way rich on the lower values, more so than necessary IMO. Your engine will probably never see the first 3 counts unless it's stalling. The only way to tell if you did a bad thing would be to check the BLM's at idle.

You shouldn't have to mess with the first 3 counts at all, just from count 192 on up. You'll never see the counts value displayed since it's just part of the table in the code. If the airflow reading you're idling at is in between 2 counts and you need to adjust the BLM there, then you need to adjust both counts.

 

Well you were right KVU, and Greg, I made way too many changes to table1. Got my scan too hooked up tonight, and with car warmed up in garage, just wouldn't idle. Surging from 500-1000. At least my BLM and INT were at 128! The airflow was about 9.0gm/sec, and injector pulse width was bouncing around steadily with the idle.
From memory, I think my idle count is at #192. I'm going back to what I had before, and just messing with with one count at a time. Sometimes I just get ahead of myself! I also had code44, which is O2 lean. Never had that before!
I usually learn by trial and error.

TunerCat, what's that? This parameter is only in the latest .ecu file for WinBin.

WinBin; what's that!!?? LOL. No fair. Looks we need to get that parameter added.

Thanks for all your help, folks.

 

I just found this thread, and I'm damn glad I did. EXCELLANT. I was starting to get the idea(I bought my IROC a month ago, and been researching/playing since), and this really helped.I've scanned my car at idle, and its pretty lean. Cant travel with scanner as of yet(no battery in laptop, damn thing is spendy)but wanting to fix somewhat "unacceptable" idle. Im really happy to see a few other MAF guys on here, as mine is an 87 350. I have alot of knowledge in tuning, but not so much with factory efi, so some of the terms were new to me, and was feeling somewhat overwhelmed.BTW, i made a notebook of sorts from this thread, just coppied and pasted the best parts into a new word doc, and made a tuning file on my comp for "Camaro tuning help". Now i am making a library of stuff for ref, so i dont have to worry about forgetting which thread I got the info from. Thanks, and I'm sure I'll be back. Hope to be able to help you all sometime as much as you've helped me.
Bob

 

I will tell you a funny thing. I have found that SOMETIMES you have better driveability (i.e. when just starting off from an idle at light-moderate part-throttle) to run a tad rich at idle.

I've done a lot of experimentation with my car and found I prefer 124 at idle for "tip in" when just starting off. Much smoother than if I have it idleing at 128/128. I have noticed an occasional "stumble" when starting off at moderate part-throttle (at lighter or heavier throttle the stumble is not there). At 124 at idle, I have no stumble what so ever....and I've played with virtually everything. It's just my personal preference.

Besides, when I first started tuning my car, it use to idle at 116.

 

So Idleing a little richer than 128 will help the tip in?
Idleing now at 128 ive gotten rid of almost all of my tip in problems but sometime i notice a hint of one when using very lite
off idle throttle opening - i was thinking of trying to lower the % to enable pump shot but maybe ill try to richen up a little instead.

 

Bravo Fellas....

Some very nice information in here!

I will be sure to include a few of these techniques in my next chip...

I am currently idling at 150 Blm after gutting my MAF. I have not been too concerned since the WB still reads 14.6 at idle.

As soon as I touch the gas the blms go to right around 128.

Still I will play with these and find where it should be.

Thanks for the instructions!

Cheers!

 

Yeah, I've got a bit of a stumble in open loop, I'm running about 132 at idle. (Cell 0)

The only problem is I'm running 122 at the same gr/sec in cell 1. That's why I'm trying to do that 3D graph, so hopefully I can play with the timing a bit to cure this.

 

A slight richness @ idle does work better for my engine.Smoothes the idle a bit.The reason I stated to get it to 128 is to understand how to change your idle mix.There is alot of misinformation out there about maf.What scared me when I started is most people have speed density on this board.I found out thats why I did'nt get much response to advanced questions.One problem is (some)people giving advice on maf when owning and tuning sd.Some things are universal but,in general the maf has to be tuned it's own way.I am glad to see what I have learned has help people.

 

And, there are some of us SD owners how have worked on MAF cars also. In fact, all the guys I've physically helped have MAF cars. The only SD car I've physically touched is my own.

It's nice to know the similarities and differences between both.

 

Glenn I know folks like you know your ****.I was'nt meaning peeps like you .

 

Glen, could you explain a little bit about the "tip in" that you are referring to? I seen it before, kind of have an idea, but want some more.

I been still working on the this idle BLM. Right now I am at BLM=122 INT=125 in cell=0. I am just messing with MAF table 1 count#192. I just changed it from 5.9 to 5.8, so I will see how it works.

I really like these flash chips now!

 

Good info!

Does anyone have anything to add?

 

just a little input for all you that dont understand the maf counts on tuner. ive been using tuner and could not figure out what the counts actually meant. im now using tuner for everything except the maf tables. for the maf tables, i am using gmecm edit. it uses voltages instead of counts. moates software also uses voltages. so, if the car is rich at idle, read the voltage from moates software at idle, go to gmecm edit maf table one and find that voltage and make the change to correct. like kvu said, then smooth out the surrounding voltages to correct the idle. hope that helps some of you. works great for me.