94 mustang mass air question

gtcobra302

Member

Sep 6, 2005

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Centra Florida

Oct 7, 2008

#1

• Oct 7, 2008

• #1

My buddy has a 94 mustang GT. It is running weird, and really rich. There is an exhaust leak at the header where it bolts to the h-pipe and when I am leaning over the motor and the car is running it is so rich I can smell gas and it hurts my eyes(there are no fuel leaks). But back to the thing I noticed. On my 89 gt when I un-plug the mass air sensor while the car is running it dies. But on his car when if you un plug the mass air sensor the car keeps running exactly the same. Which leads me to believe that his mass air sensor is bad thus causing the computer to go into safe mode and in turn the car runs rich. Sound about right?

 

HISSIN50

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Oct 7, 2008

#2

• Oct 7, 2008

• #2

Have him pull codes. If it's running in FMEM, the CEL should be on and a code will be present.

 

gtcobra302

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Sep 6, 2005

118

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Centra Florida

Oct 7, 2008

#3

• Oct 7, 2008

• #3

I am sorry, not to be an ass hole but, pretend I am retarded and explain that again. Thanks

 

95Vert

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Aug 19, 2004

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Oct 7, 2008

#4

• Oct 7, 2008

• #4

When you disconnect a MAF on an 94-95, the car WILL stay running. I've tried that before. IMHO, I think that the exhaust leaking is causing all the symptons because the O2 sensors are getting 'false' readings causing them to dump more fuel. Fix the leak, problem fixed.

 

HISSIN50

"How long does it take to get help in here?

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Oct 8, 2008

#5

• Oct 8, 2008

• #5

gtcobra302 said:

I am sorry, not to be an ass hole but, pretend I am retarded and explain that again. Thanks

Click to expand...

Pull the trouble codes. This will help in finding the source of the issue.

As for the other part of my post, FMEM is the mode the EEC runs in when there's a major sensor disconnected [or one that went bad]. The EEC disregards that sensor's input, and it can run rich while doing so. This will also generate a trouble code.


Also note that if the purge solenoid lines crack, you can get a good fuel smell going. The cannister is inside the passenger fender liner under the antenna). The purge discharge line runs along the passenger firewall.

Good luck.

 

gtcobra302

Member

Sep 6, 2005

118

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Centra Florida

Oct 8, 2008

#6

• Oct 8, 2008

• #6

How do I pull the codes

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Oct 8, 2008

#7

• Oct 8, 2008

• #7

gtcobra302 said:

How do I pull the codes

Click to expand...

HISSIN50 said:

Pull the trouble codes.

Click to expand...

Hyperlinks are easy to miss.

 

95Vert

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Oct 9, 2008

#8

• Oct 9, 2008

• #8

Why not fix the leak and see what happens...

 

Zero_chance

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Oct 9, 2008

#9

• Oct 9, 2008

• #9

The exhaust leak is a possibility as if its sucking in air before the o2, the comp will assume its coming from the motor and will try to compensate by adding more fuel. Usually will be accompanied by a code. Not sure exactly what the code is on our cars but its usually a p0171 or p0174 for obd2. Though there are other possibilities, and checking for codes is always a good idea.