HELP! runs worse with new MAF!

[1realsleeper]

Edit:
I had a 126 code (MAP or Baro out of range) and that was all. So I replaced the "MAF" sensor... yea... I did that lol.
With the new aftermarket MAF, the car now runs worse than before and gave me other codes. (Still 126, now a 157 with KOEO. And a 411 with a KOER)

So... do you guys think it's the new MAF that is causing the issue due to being incorrect for my application? Or is there new MAF exacerbating another issue with the Map/Baro?

This is on a 1992 mtx btw. Thanks.

 

[luigisho]

I've never really had a good experience with aftermarket MAF's. I would get a used oem unit before I bought a new aftermarket part. Just my personal experience.

You may have a problem with it relearning idle and chances are high that the old data from the old part is used to develop the adaptive tables in the computer and those are not similar to whatever the new part is reading. I would do as you did by draining the power, running it with the new part, and make sure you get enough idle and different driving events so the computer can 'relearn'. Sometimes it takes longer than you think it should. Don't forget different loads on the car like ac compressor and such. Give it longer than you think is reasonable and see how it's running.

 

[1realsleeper]

Would that cause additional codes?
I didn't have a MAF code before (though I thought I did lol) and now I do have a maf code with a new MAF.
Seems odd...

 

[luigisho]

Ok well you can do a swap/memory clear with both parts to verify it only appears with the new and the old has no code. What part did you put on there? MAF is finnicky on these cars even without codes. i had a bunch of aftermarket MAF's over the years and none were better than stock. Most worse. Even the better ones could have used a tune to dial them in.

 

[kevinspann]

It sounds like you need to replace the MAP sensor that is mounted to the firewall.

 

[1realsleeper]

It sounds like you need to replace the MAP sensor that is mounted to the firewall.

I just ordered one. I'm sure that will take care of the the 126 code. Just not sure about the new codes (157, 411)
I'll report back tomorrow when I get the MAP in and switch MAF's.

 

[luigisho]

and I guess the MAP will also come up as a BAP when you order? The SHO unit doesn't attach to the manifold so they call it a barometric vs manifold sensor. pretty much same thing without a hose to the manifold

I wonder if the BAP is disconnected will the car run in a closed loop default or if it will just run terribly? Stuff like the MAF will run with a default value when unplugged, which isn't great but usually better than if the part is malfunctioning

 

[1realsleeper]

and I guess the MAP will also come up as a BAP when you order? The SHO unit doesn't attach to the manifold so they call it a barometric vs manifold sensor. pretty much same thing without a hose to the manifold

I wonder if the BAP is disconnected will the car run in a closed loop default or if it will just run terribly? Stuff like the MAF will run with a default value when unplugged, which isn't great but usually better than if the part is malfunctioning

I called in to a buddy at a local AdvancedAuto. I just told I needed a Baro/BAP sensor. I am assuming he knew what it was lol. Ill stop by today and see if it's right. (Haven't paid yet, so no harm)

That's a good question about the BAP.
I honestly just realized that was what the 126 code was for. I haven't even located it on the firewall, just know what it looks like via searching and past experience.
Where should it be located?
It might not even be there/connected...

Edit: is this the BAP? (I'm at work and don't have my manuals with me. Just going through old pics lol)

 

[luigisho]

yep here is a test thread http://www.shoforum.com/index.php?threads/how-to-test-a-barometric-pressure-sensor.114487/

Good pic here on post #24 http://forums.tccoa.com/9-engine-3-8l-4-2l/135975-help-me-solve-puzzle-cant-too-hard.html

 

[1realsleeper]

Thanks bud

 

[1realsleeper]

Picked up the new BAP today. It looks exactly like the pic you linked to above.
It's $76.00 at Advanced Auto, before tax. I used my discount and my buddy hooked me up with a coupon, which brought it to $60.00 after tax. SCORE!

 

[luigisho]

Let's see how it works. You might have to do a computer reset a few times to sort out the BAP MAF stuff. Maybe even a fault elsewhere but you have to eliminate obvious stuff first

 

[luigisho]

Any progress?

 

[1realsleeper]

Any progress?

Yes.
Old MAF and new BAR and she is purring like a kitten. I sent the MAF back.