Author Topic: NO SPARK 79 TA 400  (Read 946 times)

Jolo

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NO SPARK 79 TA 400
« on: May 30, 2021, 10:34:37 AM »
Not getting spark. I followed all the diagnostic  tests in the Pontiac Service Manual.  Everything checked out including   Pick up coil and coil.  So per the manual, I replaced the ignition control module, to no avail; still no spark.  I don’t see that the 79 models have an ignition relay, so any ideas what is causing my problem?  I checked the number one and the number two plugs for spark to rule out bad wires or cap.  Everything points to the ignition control module. 


NOT A TA

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Re: NO SPARK 79 TA 400
« Reply #1 on: May 30, 2021, 06:17:51 PM »
I've seen bad new ignition modules. They're pretty cheap so try another. Should always have a known good spare anyway.
John Paige
Lab-14.com

Jolo

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Re: NO SPARK 79 TA 400
« Reply #2 on: May 30, 2021, 08:57:37 PM »
Agree.  I bought this new cheap module to pin down the problem but I want a complete new distributor.  I know I’ll buy another module then one of the coils or the wiring harness  goes and I am stranded on the road. I assume this is the original distributor.   The module was the first thing to go months after I bought my new 78 trans am.  At the time, my uncle who was a mechanic, told me the modules were a weak point in the ignition.   


Jolo

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Re: NO SPARK 79 TA 400
« Reply #3 on: June 13, 2021, 11:51:44 AM »
Installed a new complete distributor with all new internals: new coil, pick up coil, ignition control module, cap and rotor.  Still no spark.  The battery cranking volts is 9.9, so not great, but service manual says anything over seven should produce spark, others say it must be over ten volts, but the engine is cranking just fine.  Can't imagine it's the battery, but the only options left appear to be taking the battery out and charging it, or simply install a new battery.  Any other possible culprits?


firebirdparts

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Re: NO SPARK 79 TA 400
« Reply #4 on: June 15, 2021, 08:52:33 AM »
I don't see how.  The distributor is a standalone item.  It just needs power.  You could power it off your daily driver at 12 volts and see what that does.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

Re: NO SPARK 79 TA 400
« Reply #4 on: June 15, 2021, 08:52:33 AM »

Jolo

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Re: NO SPARK 79 TA 400
« Reply #5 on: June 15, 2021, 09:27:40 AM »
So, I discovered a major mistake.  While I ran my oil pump counter clockwise to prime the engine, I had a mental lapse or force of habit error, and I wired the distributor cap for a small block Chevy (clockwise).  As soon as I get a new set of ignition wires, I will rewire the cap counterclockwise and report back.  I would have thought I would get spark running either way, but not starting, but we shall see once I get it corrected.

jonathonar89

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Re: NO SPARK 79 TA 400
« Reply #6 on: June 15, 2021, 09:40:21 AM »
So, I discovered a major mistake.  While I ran my oil pump counter clockwise to prime the engine, I had a mental lapse or force of habit error, and I wired the distributor cap for a small block Chevy (clockwise).  As soon as I get a new set of ignition wires, I will rewire the cap counterclockwise and report back.  I would have thought I would get spark running either way, but not starting, but we shall see once I get it corrected.

Even if you wired the plugs in the wrong order, you should still be getting spark.

Get a test light or other basic power tester.  Make sure that distributor power wire is supplying power and work forward.  You’ll get it figured out.

I love HEI/distributors.  So much easier than efi systems.  CNP/COP ignition is badass but so much more complex at the same time.

NOT A TA

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Re: NO SPARK 79 TA 400
« Reply #7 on: June 15, 2021, 11:53:39 AM »
So, I discovered a major mistake.  While I ran my oil pump counter clockwise to prime the engine, I had a mental lapse or force of habit error, and I wired the distributor cap for a small block Chevy (clockwise).  As soon as I get a new set of ignition wires, I will rewire the cap counterclockwise and report back.  I would have thought I would get spark running either way, but not starting, but we shall see once I get it corrected.

You should get spark even with the plug wires placed incorrectly. Typically you'll get an occasional pop through the intake if you set up a Pontiac V8 using the SBC wire placement if everything else is operating correctly.
John Paige
Lab-14.com

Jolo

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Re: NO SPARK 79 TA 400
« Reply #8 on: June 25, 2021, 06:08:36 PM »
Getting close to closing this dilemma. I disconnected the tach wire to the distributor to check its cranking voltage (the voltage at the battery wire to the distributor previously checked out fine).  The voltmeter attached to tach wire showed zero voltage with the key in the “on” position and when I moved the key to start, the car did not hesitate and started immediately. 

I did have the dash pod out to replace the speedometer.  I doubt I could have connected the tach wire incorrectly, but I can’t imagine what else could be off.   Any ideas why the car will not start with the tach connected to the distributor?

Jolo

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Re: NO SPARK 79 TA 400
« Reply #9 on: June 26, 2021, 09:48:39 PM »
Problem solved.  I had the gauge cluster out to replace the speedometer.   Because the tach wire is so short, I added extensions to each of the terminal ends on the “L” shaped connector that cannot be incorrectly attached to the gauge cluster.  However, if not careful, my extensions can be and were crossed.  I ditched my extensions and felt around blindly for a minute or so until I got the “L” connecter attached to the gauge.  Car starts right up and runs well. 

Thanks for all the support. 

Re: NO SPARK 79 TA 400
« Reply #9 on: June 26, 2021, 09:48:39 PM »
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