81f100custom Posted February 5, 2019 Share Posted February 5, 2019 Anyone have any wiring diagrams for the 81 F100? Looking for all of them but in particular ignition wiring. I looked under diagrams up top but all I found was 85 and 86. Thanks Link to comment Share on other sites More sharing options...
Hstrymkrs Posted February 5, 2019 Share Posted February 5, 2019 Here it is... http://www.garysgaragemahal.com/start-ignition--carb-circuits.html Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 5, 2019 Share Posted February 5, 2019 Here it is... http://www.garysgaragemahal.com/start-ignition--carb-circuits.html Yep, the EVTM is better than the wiring diagrams as it breaks the schematics into individual circuits and describes how they work. In the screenshot below you can see how to get to the 1981 EVTM's index via the red circle, and from there you'll see the Start, Ignition, & Carb Circuits. But you probably went to the yellow highlighted Wiring Diagrams, and there are only the '85 and '86 there now. I have the '81 in paper form, but just haven't scanned it - yet. Link to comment Share on other sites More sharing options...
81f100custom Posted February 5, 2019 Author Share Posted February 5, 2019 Yep, the EVTM is better than the wiring diagrams as it breaks the schematics into individual circuits and describes how they work. In the screenshot below you can see how to get to the 1981 EVTM's index via the red circle, and from there you'll see the Start, Ignition, & Carb Circuits. But you probably went to the yellow highlighted Wiring Diagrams, and there are only the '85 and '86 there now. I have the '81 in paper form, but just haven't scanned it - yet. Thanks, you are exactly right I went to the wiring diagram that is highlighted. Trying to figure out maybe if I have a problem with the switch on the steering column as I am getting no fire. Will spin over just fine but not firing. It done this a few months back and I noticed when you back the key switch up as to the off position it would fire. It has been doing just fine since I started just giving it a quick twist and letting up until yesterday now it is back to not firing. Swapped the ignition module box on the fender but same thing just to try that. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 5, 2019 Share Posted February 5, 2019 Thanks, you are exactly right I went to the wiring diagram that is highlighted. Trying to figure out maybe if I have a problem with the switch on the steering column as I am getting no fire. Will spin over just fine but not firing. It done this a few months back and I noticed when you back the key switch up as to the off position it would fire. It has been doing just fine since I started just giving it a quick twist and letting up until yesterday now it is back to not firing. Swapped the ignition module box on the fender but same thing just to try that. Check out the Ignition Switch tab here: Electrical/Ignition. It shows how to clean as well as adjust the switch. Link to comment Share on other sites More sharing options...
Hstrymkrs Posted February 5, 2019 Share Posted February 5, 2019 Thanks, you are exactly right I went to the wiring diagram that is highlighted. Trying to figure out maybe if I have a problem with the switch on the steering column as I am getting no fire. Will spin over just fine but not firing. It done this a few months back and I noticed when you back the key switch up as to the off position it would fire. It has been doing just fine since I started just giving it a quick twist and letting up until yesterday now it is back to not firing. Swapped the ignition module box on the fender but same thing just to try that. I had this same problem on my 1994 Ford Tempo a while back. FWIW, it was the contacts in the ignition switch "box" that was coming loose. What I mean by this is the plastic housing was coming loose from the metal base. I pinched the tabs back in and this tightened the "box" back up. No problems since. Please check everything else, but it seems odd that it fires when the switched is turned back. My Tempo would run as long as I held the key half way between start and run. As soon as I let go, the spring would disconnect it. After pinching the tabs back, it worked as it was suppose to work. William Link to comment Share on other sites More sharing options...
81f100custom Posted February 5, 2019 Author Share Posted February 5, 2019 I had this same problem on my 1994 Ford Tempo a while back. FWIW, it was the contacts in the ignition switch "box" that was coming loose. What I mean by this is the plastic housing was coming loose from the metal base. I pinched the tabs back in and this tightened the "box" back up. No problems since. Please check everything else, but it seems odd that it fires when the switched is turned back. My Tempo would run as long as I held the key half way between start and run. As soon as I let go, the spring would disconnect it. After pinching the tabs back, it worked as it was suppose to work. William Thanks much for the replies and help. I believe and feel it is something simple just like you described. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 5, 2019 Share Posted February 5, 2019 Thanks much for the replies and help. I believe and feel it is something simple just like you described. Let us know, we can help you work through it. Link to comment Share on other sites More sharing options...
Steve83 Posted February 5, 2019 Share Posted February 5, 2019 Thanks much for the replies and help. I believe and feel it is something simple just like you described. This caption explains how to test an ignition switch: https://supermotors.net/getfile/831772/thumbnail/igswlogic.jpg Link to comment Share on other sites More sharing options...
81f100custom Posted February 7, 2019 Author Share Posted February 7, 2019 This caption explains how to test an ignition switch: https://supermotors.net/getfile/831772/thumbnail/igswlogic.jpg Well just a quick update drove the truck to work Monday morning no problem cranking what so ever. Got off that evening motor just spins over not firing messed with it a little more nothing just spinning over. Head on home Monday evening after catching a ride and look over the wiring diagrams head back to work Tuesday and going to try jumping some things to see if it will crank. First tried jumping straight from battery to batt side of coil while cranking still just spinning over. Tried just putting the switch in the run position and jumping across the solenoid so the switch would not have to be moving still the same result. Tried checking the 12 volts that goes to the ignition module red/bl wire while cranking was showing voltage at that time. Swapped ignition boxes once more just to see if that made a difference still just spin over. Plugged back up the one still mounted on the fender and messed with the connections as it was spinning over. It sounded like a time or two it wanted to crank but did not. Running out of ideas to keep trying after staying after work late I decided I would just have it towed to the house Wednesday. Meet tow truck driver in the parking lot and he ask what is going on with it need a jump or something else. I told him it would just spin over but not firing and I told him just a sec and I will show you. Well what do you know I open the door reach in give it a quick start to show him and it cranks like brand new. Turned it off tried it again cranked just soon as you touch the switch. I cranked it once more back it out of the spot pulled it up to his truck cut it off let him load it and take it to the house. Got home last night cranked and drive it about 8 miles or so working like brand new again. I guess now instead of trying to get it to work I will have to try and not get it to work to try and figure this aggravating problem out. Link to comment Share on other sites More sharing options...
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