1995 Ford F-150 Mass air flow

Tiny
SMOKINYA
  • MEMBER
  • 1995 FORD F-150
  • 5.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 158,000 MILES
I was throwing a code for the mass air flow change it as soon as you plug the maf in the trucks starts to die unplug and truck runs. I checked the voltage going to the maf none it's suppose to have 12 so I plug it in and give it 12 volts to the hot wire trucknow begins to die
Thursday, November 12th, 2015 AT 7:03 AM

5 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
What is the vehicle vin? That voltage may come from power relay. When you unplug sensor, the computer may have used default maf signal. I believe that relay should energize when you turn on the key. There are several systems that use that same voltage. You may have to do continuity test on wire for maf voltage. I know you jumped voltage to that circuit, maybe no signal is better than faulty signal if the computer uses a default value.

What was the actual code #, I guess I can look it up? I can only talk to you about the basics. The expert title under my name, I think refers to how many questions I've tried to answered and not my expertize.
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Thursday, November 12th, 2015 AT 11:01 AM
Tiny
SMOKINYA
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  • 3 POSTS
I have looked into the relay and it is working as it should I was wrong on the first part I did have voltage but it was only around 5 volts but that's just a reference voltage for the truck to the maf
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Thursday, November 12th, 2015 AT 11:25 AM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
What is your vin? I looked up vin n for your year--make--model and engine size--automatic. Voltage from load side of that relay is 12 volts and goes to several systems besides the maf. Ref voltage won't come from a relay in my opinion, ref voltage comes from computer.

It is possible I was looking at wrong wiring diagram?
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Thursday, November 12th, 2015 AT 3:16 PM
Tiny
SMOKINYA
  • MEMBER
  • 3 POSTS
I'll post the Vin as soon as I can but I believe so because I ended up pulling the connector to computer and testing the wires to the maf and relay to make sure nothing was broke and everything checked ok I'm almost to where I think the computerm may be junk
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Thursday, November 12th, 2015 AT 3:27 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
My thought was maybe a faulty maf sensor? Don't replace anything unless testing points you in that direction.
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Friday, November 13th, 2015 AT 12:28 PM

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