Author Topic: 79 403 ignition help  (Read 5118 times)

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Offline moonrider1

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79 403 ignition help
« on: May 11, 2006, 10:21:31 PM »
Guys I am still having trouble getting my 403 running again. The car was idling one day in my drive way and then just quit. A month or so before that I had changed out the plugs, wires, cap, and rotor. Everything was running fine for several weeks. Now I have fire at the batt side of the distributor but nothing at the plugs. I have checked more than one plug also. Nothing.

Since this problem started, I have changed out:
module
pickup coil
ignition coil (2 different ones have been tried)
condenser & harness assembly
distributor cap (again)
rotor (again 2 different ones tried here also)

There is nothing else inside the distributor that I can change out. I am stumped at this point. Is there anything outside the distributor that would cause the plugs not to fire. I tested the batt side terminal of the distributor while the engine is turning over with the starter and my test light stays lit. I checked with a volt meter and am getting 10.8 volts to the distributor. Should be plenty to fire the engine but still no fire at the plugs. What else would cause my plugs not to fire with power going into the distributor? Can anyone give me some hints with this please?
79 10th anniversery T/A 403 Auto
78 Solar Gold Y-88 SE T/A 400 Auto
74 Camaro Type LT Z28 350 - 4 speed
66 Ford Mustang 2+2 Fastback 289 - 4 speed

Offline ta78w72

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Re: 79 403 ignition help
« Reply #1 on: May 11, 2006, 10:49:25 PM »
It's too hard!  You really need to go through the service manual diagnosis.  It could be a fautly bulkhead connection (for example....I'm not saying it is).  But go through the process....it's probably something very simple.  Do you have a spare ignition switch?  If so, you haven't changed that.  But you really don't want to get into a parts changing situation.  

There is a simple test for the coil in the service manual.  It doesn't do any good to keep changing them.....But I realize it gets very frustrating.  There's also a test for the pickup coil in the service manual.

Here's what I would do...
1. Order a service manual from Brett
2.  Take off your cap and go through the test for the coil (that will validate that you have the coil installed properly)
3.  Start from the beginning of the diagnosis test per the manual and work your way through it

You did verify that you aren't getting current to the plugs, otherwise I'd suspect that your timing chain could have jumped.

The best way to figure out if your plugs are firing is to attach the timing light to the plug wire and see if the light fires.  They work off induction.

I know it seems like it's impossible to figure out, but go through the process and you will figure it out....and you'll never, ever forget.

Offline Tin Indians Rule

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79 403 ignition help
« Reply #2 on: May 12, 2006, 07:19:43 AM »
I agree completely with Russ. You need to get the manual and field test each part now in the chain of order. Eliminate one as being faulty and move on to the next one until your testing reveals the faulty part.

Did you replace any parts with used parts? Like the module???? Have you checked to be sure that your rotor button is turning as the engine spins over?

On a side note.... Thanks for the harness. It's really in great condition.
What's she wearing now? Come on!
1976 Black 455 4 speed (current project)
1976 White 400 Auto (original)
F-body stuff stashed everywhere.
Always buying/selling/trading  just ask!

Offline moonrider1

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Wiring harness
« Reply #3 on: May 18, 2006, 11:20:03 PM »
Just an update on my ignition problem.  Took the advice and did all of the tests.  Narrowed it down to my ignition switch on lower part of the steering column.  Changed it out and bingo!  Fired right up.

I'm glad the wiring harness worked out for you.
79 10th anniversery T/A 403 Auto
78 Solar Gold Y-88 SE T/A 400 Auto
74 Camaro Type LT Z28 350 - 4 speed
66 Ford Mustang 2+2 Fastback 289 - 4 speed

Offline Tin Indians Rule

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79 403 ignition help
« Reply #4 on: May 19, 2006, 12:58:25 AM »
Ed, glad you got the ol bird fired up.
What's she wearing now? Come on!
1976 Black 455 4 speed (current project)
1976 White 400 Auto (original)
F-body stuff stashed everywhere.
Always buying/selling/trading  just ask!