4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

car is falling flat on its face at like 3500-4k.

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Old 06-23-2009, 10:47 PM
  #71  
justinschmidt1
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Originally Posted by WhiteFoxGT
The MAF could very well cause this.

lol excuse the edit

The 95 GT I had was an auto and it did the same thing. Right around 4000rpms it would just die, like rev to 4 smooth then take FOREVER to get to redline to shift. MAF was the culprit. What voltage are you seeing at idle? .6, .7?


Yea...it runs "normal" up to about then...then just dies basically.

I wont keep in it long enough for it to rev to redline cause im scared to hurt something but Im assuming it would eventually make it htere.


I havent datalogged the voltage.

I did datalog airflow count or something , would that help?
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Old 06-23-2009, 10:52 PM
  #72  
WhiteFoxGT
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What you really want to see is voltage. I dont remember specific #s but I believe its around .5,.6 at idle then Im not sur what it shoots too at higher throttle. Theres NO dtcs at all? KOER, OD self test?, Continuous code?
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Old 06-23-2009, 10:55 PM
  #73  
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Originally Posted by WhiteFoxGT
What you really want to see is voltage. I dont remember specific #s but I believe its around .5,.6 at idle then Im not sur what it shoots too at higher throttle. Theres NO dtcs at all? KOER, OD self test?, Continuous code?
no dtcs....I even tried looking with the tuner, nothin at all.


Ill check the voltage tommarow.

Last edited by justinschmidt1; 06-23-2009 at 10:59 PM.
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Old 06-23-2009, 11:22 PM
  #74  
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How did you clean the MAF?
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Old 06-23-2009, 11:29 PM
  #75  
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Originally Posted by Smokin04
How did you clean the MAF?
steel wool....

lol

I used that stuff that comes in a can...the MAF cleaner spray

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Old 06-23-2009, 11:43 PM
  #76  
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That's the right stuff to use. And this just happened all of a sudden huh? It must be a broken part or faulty sensor of some kind.

Regulator - Most likely

You also need to bring this back to your tuner...it might also be a bad internal PCM ground. There are 7 of them, he might be able to tell you yay or nay.
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Old 06-23-2009, 11:46 PM
  #77  
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Originally Posted by Smokin04
That's the right stuff to use. And this just happened all of a sudden huh? It must be a broken part or faulty sensor of some kind.

Regulator - Most likely

You also need to bring this back to your tuner...it might also be a bad internal PCM ground. There are 7 of them, he might be able to tell you yay or nay.
Yep, I boosted one night, through second/third, ran great, the next day it was acting like this.

hmm...bad internal pcm ground...what the hell is that. haha

I will ask him about the regulator.
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Old 06-23-2009, 11:55 PM
  #78  
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In a regulator there is a diaphragm that could go bad and run fine during vacuum but when boost pushes on it it can open to far and let to much fuel thru.
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Old 06-23-2009, 11:57 PM
  #79  
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Originally Posted by mustangman281
In a regulator there is a diaphragm that could go bad and run fine during vacuum but when boost pushes on it it can open to far and let to much fuel thru.
Ahh, that would make sense.

I guess the only way to test this would be fuel pressure under load.

Last edited by justinschmidt1; 06-24-2009 at 12:03 AM.
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Old 06-24-2009, 12:10 AM
  #80  
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Originally Posted by justinschmidt1
Ahh, that would make sense.

I guess the only way to test this would be fuel pressure under load.
Yup. Your computer doesn't see fuel pressure which is why it won't correct the injector pulse is it goes to high. You need to get a guage.
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