79 400 dies suddenly
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Junior User
Joined: Oct 2004
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From: Queen Charlottes BC
79 400 dies suddenly
My 79 is having some ignition issues. Sometimes when I start it it will fire and die. At this point you might as well not touch that key again for 5 minutes otherwise you almost kill the battery. Also when you drive it around it sometimes just shuts off and again you have to wait 5 minutes and it will run great again. This problem is far from consistent. Changed the fuel filter, checked the vent on the gas cap, cap and rotor seem dry and in good shape. I was told by some coil and others the brainbox. I hope it is the coil because it has a fairly new msg brainbox. Any help would be appreciated. Thanks in advance.
Laughing Gas
Joined: Jul 2002
Posts: 843
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From: USA
Before I converted my ignition system over to TFI I carried a spare module under my seat all the time. They are too sensitive to the environment to ever be without one. The age of the module makes no difference on it's performance. Take your's and have it tested at the local Autozone(or equivalent) and see what happens. It sounds like it gets hot, even at startup, and has to cool down. When you mount it on the inner fender place 4 1/4-20 nuts under the unit to raise it up from the sheet metal. This allows a little more air to get around the unit. Hope this works.
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Junior User
Joined: Oct 2004
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From: Queen Charlottes BC
still fighting
Thanks, I am thinking of changing over to an updated type system. I put a timing light on the leads and at startup it is nice and steady for about 45 to 1 minute and then the spark gets eradict. Going to look into different options. I have been told magnetic pickup, coil, brainbox. Going to call Lordco on Monday.
Thanks
Thanks
Posting Guru
Joined: Jun 2005
Posts: 1,070
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From: charlotte, nc
it kind of makes me think you have vaporlock in your fuel line, i had that problem with my ole 78 with the 400. it was a real inconsistant problem, but i fixed it my adding a piece of rubber fuel line between the fuel pump and carb.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
My 79 is having some ignition issues. Sometimes when I start it it will fire and die. At this point you might as well not touch that key again for 5 minutes otherwise you almost kill the battery. Also when you drive it around it sometimes just shuts off and again you have to wait 5 minutes and it will run great again. This problem is far from consistent. Changed the fuel filter, checked the vent on the gas cap, cap and rotor seem dry and in good shape. I was told by some coil and others the brainbox. I hope it is the coil because it has a fairly new msg brainbox.
Many autoparts stores sell modules that are made in China, these are pure unadultrated CRAP!
Many autoparts stores sell modules that are made in China, these are pure unadultrated CRAP!
1) Module overheats, engine dies. Module cools down, engine restarts almost immediately.
2) Module overheats, engine dies. Module cools down...engine restarts in an hour or so.
3) Sooner or later....usually sooner, the module overheats...BURNS OUT. Now the engine will not restart.
> > In addition to the module, inside the dizzy is a stator aka pickup coil...which can exhibit the same symptoms. < <
The stator is the same: 1974/79: D4PZ12A112A (Motorcraft DU1A).
The following is the most common module used 1976/79:
1U2Z12A199AA .. Ignition Module (Motorcraft DY893) / 1U2Z-12A199-AA replaced D9VZ-12A199-A
Just above where the wires feed out from the module, this particular module has a BLUE plastic square.
Engine heat, especially on V8's, is the mortal enemy of these modules, which thru 1979 are mounted on the left inner fender apron just in front of the firewall.
When replacing it...use some washers to space it further out from the apron.
The more airflow around the little darlin' the better.
New User
Joined: Feb 2009
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I had a '79 do the same thing and it was the ignition coil. Not the pick up coil, the black can coil.
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Senior User
Joined: May 2009
Posts: 347
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From: Skyway, WA
I've suffered similar symptoms with my 76 F 100 pickup. Today I discovered that the wire that supplies the ignition switch with power from the Battery/Alternator is intermittent. Manipulating the wire near what I believe is the fusible link, caused the ignition switch to have power or not have power. I could kill the engine by touching the wire. Something to think about.
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New User
Joined: Oct 2008
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Bill (or anybody) is there an aftermarket fix for the parts prone to failure? My '79 Bronco has had an intermittent semi-engine failure for a couple of years. It doesn't die, but barely runs. I swapped out the coil, and rebuilt the carb (original 2150), which had a significant amount of strange pinkish stuff in the fuel bowl. Large pieces, much too big to get through the filter. It has run fine since both of those operations, but I'm still wondering.
Thanks, all, for the info.
Thanks, all, for the info.
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