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MAF wiring problem


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Mark Carter
New User

Jul 20, 2017, 5:03 PM

Post #1 of 8 (1436 views)
MAF wiring problem Sign In

I have a 99 Mustang 3.8 V6 with many miles on it . I am getting a PO 102 code MAF low input. I bought a new MAF sensor and a K and N air filter because the car is 18years old. I am getting 12 volts at the MAF sensor and a good ground that reads 000. The two other sensor wires on the plug are shown to go to the Control Module on the wiring diagram. How can I check the other signal wires ? I may have a slight intake manifold leak but probably not much because the car idle goes up and down on the tachometer and at Idle the car lunges forward slightly
Does the 102 code mean a low input of electricity or does it mean a low input of air going across the wires on the MAF sensor? I cleared the code with my scanner but it just comes right back on. Their is also a PO 171 code which is a lean condition. Since the MAF sensor is new it can't be the problem right so that is illuminated right


(This post was edited by Mark Carter on Jul 20, 2017, 5:04 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Jul 20, 2017, 5:33 PM

Post #2 of 8 (1431 views)
Re: MAF wiring problem Sign In

You have both a MAF code and a lean code. That thing is getting unmetered air from somewhere and you need to find it.

PS, K&N filters are known problems for MAFs. Don't use any oil on them.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
Ultimate Carjunky / Moderator
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Jul 21, 2017, 5:17 AM

Post #3 of 8 (1401 views)
Re: MAF wiring problem Sign In


Quote
Does the 102 code mean a low input of electricity or does it mean a low input of air going across the wires on the MAF sensor?


It can mean both. The PCM is expecting to see a certain voltage range depending on it component monitoring software calibrations. If you have low air flow or a circuit issue causing the voltage to be lower than expected it will set that code.

As HT stated you should first verify you don't have any un-metered air leaks first. Torn intake boots or big vacuum leaks can cause that code to appear.





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Mark Carter
New User

Jul 21, 2017, 10:33 AM

Post #4 of 8 (1386 views)
Re: MAF wiring problem Sign In

Thanks guys. I think I have fixed any vacuum leaks. I have checked the vacuum areas with a stethoscope and I cant hear anything. I just put on a new intake gasket about a month ago. the car hesitates under load when I am getting on the freeway and then bursts forward all at once. It drives on the freeway really good. I had used fram air cleaners for years so I thought that a K and N might help get me more airflow but it didn't help. I probably will have to take the car to a mechanic to fix the problem.
I have been an auto body guy for over twenty years and use a scanner at work because I work on Air Bags. I think I can solve many problems on the forum with their bodywork problems. But this problem with my car seems to be a little over my head.


Hammer Time
Ultimate Carjunky / Moderator
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Jul 21, 2017, 1:55 PM

Post #5 of 8 (1376 views)
Re: MAF wiring problem Sign In

Double check the intake snorkel and any attached hoses for leaks.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Mark Carter
New User

Jul 23, 2017, 2:53 PM

Post #6 of 8 (1343 views)
Re: MAF wiring problem Sign In

Your right MT I found a hose that runs from the throttle body to the EGR outlet underneath the fender. the hose was about three feet long. The RPM at Idle seems to have become more stable and runs better but it still has some of Intake leak associations. I would like to find somebody with a smoke machine to see for sure


Hammer Time
Ultimate Carjunky / Moderator
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Jul 23, 2017, 3:08 PM

Post #7 of 8 (1341 views)
Re: MAF wiring problem Sign In

That would be a good idea.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Sidom
Veteran / Moderator
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Jul 23, 2017, 10:30 PM

Post #8 of 8 (1325 views)
Re: MAF wiring problem Sign In

I see where you said you have access to a scanner?.....

If you could look at a data stream and look at the grams per second and where the the throttle position sensor is showing the throttle at would be a big help






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