78 ford pickup firing problems

Those older cars had a parallel ignition circuit, one leg of which was active in the start mode and the other in run mode. "Run" had a resistor in series with the supply to protect points and coil.

I suspect your "Run" mode may be okay, but that the "Start" circuit has a problem.

Just my guess.

Reply to
HLS
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I have a 78 ford pickup with a 400 engine. Shut it off a few weeks ago and it would not start back up. I am not getting fire while it is turning over. As I shut off the key it will hit but not start. I replaced the coil, the electronic ignition, the distributor and rotor. Also the ignition switch. The only thing I have not replaced that I can think of is the pick up under the distributor. Has anyone else had this problem?

I checked and have fire to all the wires. Coil has fire to it and so does the electronic ignition box. Checked the coil and it fires off only as the key is shut off. The engine hits once and then does not start. Could the problem be in the pickup under the distributor. I need this truck to get wood out or its going to be REALLY cold in the house!!!!!!

Reply to
bluegillus

Might a connection, then, from the starter relay be defective? s

Reply to
sdlomi2

If I recall correctly Fords of that era used a relay, usually on the fender well, that supplied 12 volts to the starter and a smaller connector that supplied 12 volts to the coil while cranking.

Reply to
Mike Walsh

Could be a connection. It shouldnt be too hard to find the lack of B+ on Start.

Reply to
HLS

If it was a Dodge, I'd say "replace the ballast resistor". Sounds like that relay does the same job differently.

One other possibility is if the distributor has one or two pickup coils. I have seen distributors (Chrysler) with a Start and a Run coil. If so, could be the start coil.

Pete

Reply to
ratatouillerat

I replaced the major coil. Just found out there is a separate pickup coil in the distributor I have not replaced yet. If that was bad would that cause the truck to fire just as you let of the key?

Reply to
bluegillus

What confuses me is that I checked all the connections and switches. The only thing I have not replaced yet that I can think of is the pickup in the distributor. Everything else that could be changed was and the wires checked for connections. Could the pickup cause the truck to fire off as the key is released?

Reply to
bluegillus

If there's only one coil in the distributor, it should work (or not work) for both starting and running. If there are two coils (and I don't know much about Fords to even know if they used two), then one could be bad.

Have you checked the relay on the fender someone else mentioned?

Pete

Reply to
ratatouillerat

If it has only 1 pickup coil(which is diff. from the ignition coil--which you called "major" coil), & it works on the 'run' side when key is released, it should work on 'start' side IF there is no broken/open link along the 'start' side wiring coming to it. As HLS told you in the beginning, this should have been checked as a first step--in MY thinking also. I firmly believe you will find your problem in this ciruit! If/when you determine this to be the fault, please reply to HLS to thank him AND to let others learn from the outcome. Thanks, sdlomi2.

Reply to
sdlomi2

If you replaced the ignition module, the cast aluminum box with 2 electrical plugs and it still does the same thing there is a start circuit that feeds from the starter solenoid to the module. Do you have 12 volts at the ignition coil with the key on not cranking?

Reply to
golden oldie

What makes you think it's the ignition? If you spray WD-40 into the intake, will it start up as long as the WD-40 is coming in?

--scott

Reply to
Scott Dorsey

snipped-for-privacy@yahoo.com wrote in news: snipped-for-privacy@i29g2000prf.googlegroups.com:

I think you had better check your timing chain. KB

Reply to
Kevin

I concur... Had a timing gear break on a Mustang of mine. The rotor wasn't turning when I cranked the engine.

Reply to
Calab

I replaced the major coil. Just found out there is a separate pickup coil in the distributor I have not replaced yet. If that was bad would that cause the truck to fire just as you let of the key? ____________________________________________________

There is a wire from a terminal on the starter relay to the (+) terminal on the ignition coil. This wire supplies current to the coil while the relay is energized during starting.

If this wire is missing or broken, or if the relay is not making its connection, the engine will not start during cranking, but may fire when the key is released to the RUN position.

Check the voltage on the coil (+) terminal during cranking. If it is more than 9 volts, the relay and the connections are okay. If not, check the voltage at the relay terminal during cranking. If it is more than 9 volts, the wire is broken. If not, the relay is defective.

Good luck.

Rodan.

Reply to
Rodan

No I am not getting fire except when the switch is released. I checked that. And yes I tried starter fluid. Am getting plenty of gas as well.

Reply to
bluegillus

Im not too sure I remember how Fords that old were wired, SD ;>)

Reply to
HLS

My Jeep has a Ford Ignition in it...

You could be describing a failure in the 'start' circuit from the solenoid/relay on the fender to the coil's power. One of the small side posts on this starter solenoid provides power when the key is in 'start', then a ballast wire provides power in 'run'.

One quick test for this is to run a small jumper wire from the battery positive to the coil positive. If it then starts, a good clean of the solenoid connections are in order or a wire trace inside the loom looking for the broken crimp connection where the two circuits connect.

Note: If it does start this way, it won't shut down until you remove the jumper.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:
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Reply to
Mike Romain

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