Starting issues 1981 f250
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From: Marysville, WA
Starting issues 1981 f250
First post and first truck hopefully many more posts to come, if i broke any rules i apologize.
A little bit of background i recently acquired a 1981 f250 from my uncle that recently got it running again but decided he no longer had the time or the will to get it completely up to snuff and being that I've been wanting a truck for ages and i love projects i gladly took it off his hands.
Alright so heres the problem the engine doesn't try to start until you stop trying to start it, and what i mean by that is when you have the key in the start position it turns over and over but when you let the key down to the on position the engine finally starts to sound like its about to fire up, so starting it has turned into frantically pulsing the ignition between start and on position.
So what do you guys think is my ignition switch bad or is it something else?
A little bit of background i recently acquired a 1981 f250 from my uncle that recently got it running again but decided he no longer had the time or the will to get it completely up to snuff and being that I've been wanting a truck for ages and i love projects i gladly took it off his hands.
Alright so heres the problem the engine doesn't try to start until you stop trying to start it, and what i mean by that is when you have the key in the start position it turns over and over but when you let the key down to the on position the engine finally starts to sound like its about to fire up, so starting it has turned into frantically pulsing the ignition between start and on position.
So what do you guys think is my ignition switch bad or is it something else?
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Welcome to FTE. 
My firsts suspicion centers around the ignition module and its wiring... These systems are designed to feed the coil full battery voltage in START but only ~7V in RUN.
Has there been any sort of wiring hacking done at the ignition module, starter solenoid, or the distributor?
My firsts suspicion centers around the ignition module and its wiring... These systems are designed to feed the coil full battery voltage in START but only ~7V in RUN.
Has there been any sort of wiring hacking done at the ignition module, starter solenoid, or the distributor?
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From: Northeast, OK
Yes, welcome to FTE! And, I think Chris is onto the problem. Said another way, if the wiring isn't supplying voltage to the ignition when cranking, and that is done by a different circuit than in ON, then it won't fire while cranking. But, would try to start as the switch comes to ON and the engine is still spinning.
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From: Marysville, WA
I'd have to talk to my uncle, but just from looking at it the distributor and the ignition module both have been changed since well they look brand new, the starter solenoid doesn't appear to have been touched since its showing its 30 year old age. It wouldn't surprise me if something got wired up wrong just not sure where to look.
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From: Northeast, OK
If you have a volt meter, put the positive lead on the coil with the ignition switch in On, and the negative lead on a good ground. One of the two coil terminals should show ~7 volts in On. Then have someone crank it and see if the voltage goes up to ~12 volts or goes to zero. I'd bet on zero.
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Alright not quite the result we were looking for but this is what i got after figuring out how the heck to turn over the truck and check the voltages by myself i came up with this, in the on position i got 7.35~ volts when i turned over the truck got 11.40~ and stays there truck started this time which isnt uncommon after screwing around with it for awhile seems like it starts up like nothings wrong once you've just about given up on it and once you get the thing going it will start up just fine only happens when you start it from cold.
FTE Legend
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From: Northeast, OK
Your results are exactly what I would expect when the wiring and switch work correctly. So, when it won't start try that again. Now you know what to look for, so you can prove or disprove Chris' theory.
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If you have a volt meter, put the positive lead on the coil with the ignition switch in On, and the negative lead on a good ground. One of the two coil terminals should show ~7 volts in On. Then have someone crank it and see if the voltage goes up to ~12 volts or goes to zero. I'd bet on zero.
I'd test both.
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From: Marysville, WA
In the meantime heres another problem that might make her a pain to start, the choke from what ive been told doesn't work and after poking around under the hood i found a disconnected wire line thats next to the carb that leads back to a canister looking thing on the right side of the truck? correct me if I'm wrong but that seems like it might be the choke, is it worth fixing or is it an option to even just run a manual one.
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Just gotta figure out what one that might be, probably going to look into finding a service manual for this thing.
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From: Northeast, OK
What color is the wire? White with a black stripe is the choke wire from the alternator. Don't know what the canister looking thing is. Maybe a picture? Would help a lot.
Anyway, if the choke isn't broken you need it to work automagically rather than put a manual choke on. Show us what you have via pictures.
Anyway, if the choke isn't broken you need it to work automagically rather than put a manual choke on. Show us what you have via pictures.
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