MAF HELP!

Hey guys, I've fixed my vacuum problem posted here:

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/help-vacuum-line-s-t6404.htm?sid=ebce874a55c1b5eb7a1257b474b24fd9

And I got a "new" MAF and MAP from Ed Morad. Plugged them in, hooked all back together and went for a drive. No SES light or any problems. Drives just fine...but idles horribly...stutters almost dies (did once)

I plugged it in and went for a drive pretty quick, so I wonder do you have to let the car idle for a few minutes to adjust to the new MAF???

I put the old MAF back in and the stuttering stops, but it idles too high and takes too long to come back to idle....so it's a MAF issue..

Help! Do I have to let the engine learn the new ratios & such and just let it settle over a few minutes...or should a MAF just plug in and work right away???

Thanks amigos!

try cleaning out your air idle control valve. if you havnt done this allready try it. i had the same problem and the aicv was the cause. use maf cleaner

I did use MAF cleaner... sprayed it good!

where is the IAC anyway??

Could just be another bad MAF, it's used from Morad and it could just need to be returned...

Do you have a scanner? I'd be curious what the MAF readings look like at idle.

on the 95 the aicv is just to the right of the vac tee. on the 95 any way. dont know on the 96?

sounds like you are running on a VE tune. the car will idle bad when first started until it learns the trims and things get smoother.
try unplugging the MAF all together and see if the problem gets worse or stays the same.
just to be clear, you have no SES light at all now? A dead MAF will trigger a code and trac off light AFAIK.
A scanner that can monitor pending codes and maf readings would really help right about now

I wonder if a CASE learn would help?

Albertj

should be a separate code for that if it needs it. i have tried many times to do a case learn on my 96 and i have not been able to do it. (tried a tech II and tried DHP powrtuner)

I should note that the week I was waiting on parts, the battery was unplugged...

so I put new MAF in, runs fine, no SES or traction lights at all...just revs at idle (in drive or park) rose to normal then would fall real low (s/c coupler would rattle, lights would dim)

I only had MAF in for 10 minutes too...so maybe it needs to learn...

BUT, plug old MAF back in...idles fine, just when you rev it, it takes longer to come back down to idle...

Does a 96 have and IAC valve? I see a part on advanced auto, but where on the car?

I'm going to plug it in tonight and let it idle again to see if improvement happens...maybe just learning new fuel curves.....

Mr.Riviera wrote:

sounds like you are running on a VE tune. the car will idle bad when first started until it learns the trims and things get smoother.
try unplugging the MAF all together and see if the problem gets worse or stays the same.
just to be clear, you have no SES light at all now? A dead MAF will trigger a code and trac off light AFAIK.
A scanner that can monitor pending codes and maf readings would really help right about now

You should definitely get a code when the MAF is unplugged, but a 'dying' MAF (still puts out some signal, but not bad) may not set any codes. A bad MAF will make it run like crap, however.


In theory, it should not have to 'learn' a new MAF. If the MAF is working properly, it will just run right. Sounds like you may be chasing a vacuum leak or troublesome IAC as others have mentioned as well.

WHERE IS THE IAC????

It doesn't give me problems with the old MAF, just revs to high and takes time to settle.

I've gone over that vacuum system with a fine toothed comb! It's all on top of the engine isn't it? There's no vacuum lines below the UIM. I do see a connection right below the S/C...but are they're any lower, or around the belts??

Could just be a bad MAF and I'll send it back and try another....

She's been down for about 3 weeks now...kinda want to drive her again sometime

thanks guys for helping me out too..

Natesriv wrote:

WHERE IS THE IAC????

IAC is located on the side of the throttle body. Idle Air Control valve lets air in whlie for idle while the butterfly is closed. there are only 3 sensors on the TB. The MAF (u kno where that is) The Throttle Position Sensor (located right at the butterfly valve) And the IAC (the only one left)

The car will not need to re-learn a new MAF, you can switch out working maf sensors all day long and the car will never know it as long as the car is off when they are unplugged.
I suppose it is possible Morad sent a bad or dirty MAF too.

As for the vac lines, yes the lowest line is the one that goes from under the snout to the MAP sensor on the back of the motor.

HTH's

HTH?

I suspect a bad one too...but I'm going to plug it in, let it idle for about 10 and then see what happends. Ed says they've another waiting in the wings should I need to return the one I have.

And I've scoured those lines.... I don't see a crack or bad rubber anywhere!

no answer on IAC???

Natesriv wrote:

HTH?



no answer on IAC???

HTH= hope that helps

did the pic not help with the IAC?

Mr.Riviera wrote:

Natesriv wrote:

HTH?



no answer on IAC???

HTH= hope that helps

did the pic not help with the IAC?

the pic shows exactly where the IAC is.

sorry bro's I'm at work and that pic doesn't show up..I'll see it when I get home! The text does, but it's just a blank spot...oh well


But thanks for the pic (in advance!)

OKAY! Thanks for IAC pic I took it off and cleaned it. It just looks like a piston with a spring...it was blackened so I sprayed with cleaner and sanded lightly clean...wtf does it do??

Put new MAF on and started car...just let idle for 5 minutes...seemed okay (could detect some rise and fall)...then revved it....came to idle, dropped and almost died...did again...died...

turned car off

Put OLD MAF back on, no problem..no light...nothing..idles fine...took for a 10 minute spin...great! Get home put in garage, engine now warm...SES and T/C light go on... idle doesn't drop but changes...I can "feel" it!

SO!....I will return MAF to Ed Morad and get another... I THINK the MAF I bought is faulty,and the one I have is broken...so they both give differnt types of faults.


I sprayed throttle boty cleaner at vacuum connections,didn't hear a rise in RPM (to indicate a leak) so I think it's all just broken MAF's and I got a bad one (they are used by the way!) so another one is waiting for me...

More to come!

btw...if I plug in the next "new" MAF and it dies....then I'm lost like totally!

We'll see!

Do you have a Multi-meter by chance? You can check the pink wire for +12 volts and the yellow for +5 volts. You can also dive into the huge connector at the firewall and check for continuity in the yellow wire as well. More can be found here... https://rivperformance.editboard.com/series-ii-engine-transmission-f4/wire-harness-and-connector-repair-t6375.htm

no...at work I do...

I will get ONE more and we'll see...the fact that the two MAFs give different idles tells me something..
\
There are TWO wires on the MAF...is one and idle sensor?

Natesriv wrote:

There are TWO wires on the MAF...is one and idle sensor?

Short answer is NO.

The wire grid inside the Mass Air Flow sensor is there to directly measure air mass flow into the engine.
Basically, the more air molecules moving past the sensor, the more the output signal changes. On GM car's the output signal is measured in a Hz wave signal. Generally 0 to 12,000 Hz.
This info is fed to the PCM where it collects data from other sources to help accurately meter idle and cruise loads.
So, the MAF sensor has an effect on idle through to WOT but it takes a combination of many sensors info to do it accurately and correctly.

well, I'm sending the one back and trying another...we'll see!

is there every a code for a bad IAC??

Nate,
Do you have an FSM.?
If not, and you plan on keeping the car, you need to get a set off EBay.
This is where I get most of my questions answered and other peoples questions as well.
Don't get me wrong, I don't mind helping out. But I would think with your curiosity about the workings of your car you would want a set to read up on how the various systems work.
I'll have to find the IAC code if you really need it.