i have a problem with my 1992 f150. one day after coming back from work with a friend, i got in my truck and went to turn it over. it wouldnt start for ten minutes. after that it turned right over. then about ten minutes after that i was at my house and it died on me and wouldnt start for 20 minutes. after that it was fine. so i took it to autozone and had them test the battery and alternator. the battery reading was 13.55 volts and the peak amps for the alternator was reading 3.5. the normal reading for the alternator should be around 90 amps. so i bought a alternator out of the junkyard and took it to autozone where they tested it and said it was fine. i put it in my truck and let it stay there for a week. then i had autozone test it again and it read the same. so i bought a new alternator and had them test it again and this time it read 4.4 amps. does anyone know of this problem or how to fix it. the battery and alternator are brand new. all help is greatly appreciated.

 

Welcome to Ford Trucks Enthusiasts! Your post has been moved to the '87-'96 F150 and Larger F-Series Trucks forum

 

Somebody erased my post...I welcomed him first!

 

I am not too sure on this newfangled electric stuff but it looks like you are loosing current somewhere. Check the main cables and solenoid for corrosion. Since the battery and alt. are new, the cables are the main suspect. A bad ground can also do this. Even if they look ok, clean the solenoid connections, including the cable to the starter.
Let us know how it goes.

 

i checked the battery cable connections and theyre clean and tight. the bottom connecter to the alternator has a broken clip so would that cause it to read so low? i havent checked the soleniod connections yet will do that today. i also was wondering if the problem might be either the wires between the soleniod and alternator, the wires between the alternator and starter, or the wires between the battery and the alternator?

 

The alt will not put out 90 amps all the time . Was the 4 amp reading with any load on the alt?

 

yeah i took it to autozone and had them test the abattery and load test the alternator. i notice this problem the most when i turn the key on but not start the truck the battery gauge reads around the 5 to 7 range.

 

i checked the connectors to the alternator and i discovered something. the three wire connector that goes to the top of the alt. and the three wire connector that goes to the bottom of the alt. comes together by someone with a lot of electrical tape and then comes out as one green wire connected to the soleniod. is that weird or is there supposed to be only that one wire going to the soleniod? the wires dont connect to anywhere else. it just goes from the alternator to the soleniod.

 

I recently posted on this same problem, I got mine at advanced auto and they gave me 2 faulty new alternators, I took it in a 3rd time and got a good one put it in and it was working but I was pulling in about 9 amps(old one was getting 4 and the 2 faulty tested about 33) so I went and got the new pigtail harness for it and connected it and the amps shot right up, the new harness is about 7 dollars at advnaced auto, I made the rookie move of checking wires and not that harness connection. Works great now. If it is a pelldium(motorcraft) part #(p)77132 be skeptical if it is working correctly. That was the #of the 2 faulty ones. make them test it before you leave.