Hi I have posted on other boards with little help.I have a lean idle blms of 145.Everywhere else the blms are 125-132.Everything else runs great.I have a 335 stroker,solid lifter roller engine ,89 t/a ,6E.

 

And there has been lots of stuff on idle issues posted on this board.

Search on "reversion" or "idle", have a look at what's there and ask a more specific question. This usually brings one of the guru's out How big is the cam (lift/ duration)?

John

 

268dur. 550 lift.This is primarily a race car,2900lbs.But I want things right.What table do I use to richen the idle blms.My searches came up short.

 

My buddy ed keeps telling me to go see him.But he was a retard in school.At least he has a dyno,now.But I want to fix the lean idle.I have burned maybe 15-20 chips.It is lean only at idle.There is some pointed conficts about this after I searched some more.is either one right???

https://www.thirdgen.org/techbb2/sho...light=maf+idle


https://www.thirdgen.org/techbb2/sho...maf+table+idle

I can't make heads or tails on this?????

 

That's because you're kvu.

 

excuse me??That is the weirdest response?????

 

thats becuase the stock MAF suffers from dropout.youll need to diddle int eh first and second maf tables to fix that problem.

at a flow of roughly 50grs/sec the maf has pretty tight curve but at a flow of 5 grs/sec the error goes from 3% to about 5%. youll have to add soem fuel. the problem is in the sensor. its fairly linear but its not great.

 

At Turbobuick.com where there have been numerous discussions about MAF drop-out, and what it is.

The short and easy answers are, it takes a code patch to stop drop out, in the Frequency based MAFs used in the GNs, and if the internal voltage regulator is failing in the MAF, it can cause it.
Both exibit themselves at WOT, or close to it.

Can you quote a source on the 3-5% error numbers?. Even if there was why would it matter?, wouldn't the BLs more then compensate for that.

 

That sucks,I thought I could adjust something using my bin editor.Well I don't know how to patch a maf??That sucks.You know what is weird?My buddy's chip done by ED put in my car will make idle blms 125.But the pe stuff is wrong for my setup,so I don't use it.Ed won't tell me what he did,he just say's"bring it up here".Sounds like he did one of these "patches".

P.S. The gn maf is the same as my 165 pcm?

 

the maf is a new wells unit.So the voltage regulator could be bad??

 

grumpy ill see what i can do about getting a fow chart/transfer function sheet for you. ive been playing ont eh fow bench all week the error for the sensor is easily 5% at low flow levels under 200kg/hr. the stock spec is 3% but hey ??as for the maf sensor data ill post it when i can. call GM theyll be glad to tell you. as for the lean idle wel theres your 5%. blm of 140.

 

So I guess there is a patch avalable?I need that patch,those blms are driving me crazy.I knew that guy (in the links)did'nt know what he was talking about.By the second link I see he fell in line

 

what you need to do is move the MAF table scalar values in tables 1-2 up. then you need to manipululate the tables themselves to get the correct voltage/grams sec relationship for proper fueling. you could also lower the injector constant and skip raising the scalars and lower the overly rich values in the maf tabales. the only problem is youll screw the lv8 calculation up a bit like that. i dont think it would be enough to get sweaty over unless you radically lowered the table values.

 

Classic $6E lean idle.

You gotta raise the MAF scalar table 1 values abit. I went round and round with that one for a little while.

I ended up raising -slightly- mind you, the values in .55 and .73 volts.

The result--a 128 idle.

HTH,

Brian P

 

Flow bench is about immaterial.
That's a steady state condition, and that's not what a MAF is exposed to. Sounds like the error your chasing is actually reversion, or some engine related item.
To say the MAF is in error means using something like a lab grade vortex generator and seeing what the actual engine consumption to reported useage is. Thou a multigas collection and analyse might do.

As for the 5% anything more then about an air filter change is going to do that, and ANY cam change is going to mess with the reversion characteristics.

And don't forget about the error from the PCV system as the engine ages.

 

The MAF drop out was brought up by someone else and has nothing to do with your problem.

The problem does exist on the 89 TTAs, not on the 165 ecm'd cars.

 

just becuase i cant elaborate on my ability to verify this test data dont assume that your comments are even remotely correct. the Reversion in the intake manifold isnt a problem. however the reversion inside the sensor surounding the maf hot wire is. dont think you even have a understadning of the position i am in to test maf sensors. i will say i can test them to better than lab specs.

 

So what do I do grumpy?I'll take a 3000+ post are not in the appearance forum Guide the way grumpy. I want to do things right,not jerry rigged.Thanks,I've searched for about a month on this.

 

I have read all this and I'm getting confused,maf dropout,reversion???

 

personally i wouldnt do anything. the fact that the blms are 145 means the ECM is compensating for the lean condition. i already told you what to do.


get the MAF voltage your lean at. get the flow chart i posted a while back called MAF flow chart. do a search on the forums. correlate the maf voltage ot counts go to the appropriate counts reading in the maf tables and riase the grs/sec values your lean at.

 

You should probably get in touch with formula5. I'm sure he could help you out and I think that you probably already know him?

Tim

 

Who is this bloke for ula5?I read some old post with somethig like that.Is he/she still on the board?Anyways I was thinking about getting the accel gen 7 if this can't be lined out.Yes it is for a race car,but I need to run rich at idle not lean. So I guess there is no fix for this ?

 

Oh the maf table 1 needs a patch in the .55 .73 area.Where do I get the patch?Thanks alot,I wanted to learn how to do this myself.My dad keeps laughing at me.But his fat a ss has a $1000 chip+$500 in dyno time.

 

anyone know about gen7 ecm?

 

well funstick,your method worked.But will lv8 be screwed now?

 

?

 

sorry for taking so long to reply ive been pretty busy at work. 60hrs in 5 days. uugghh. and its only tuesday. i love the job but im tired.

anyways no changing the maf table values themselve will nto affect the LV8 calcs.

lv8= rpm/grs:sec x lv8 scalar.

so for instance in the $6e

lv8= 2000rpm/ 50 * 1.25 = 50 so an lv8 of 50. this doesnt affect lv8. what does affect LV* is dropping the MAF input voltage to scale for a bigger maf. then changing the LV8 constant is required to bring the timing tables back on center.good luck and have fun.