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Lramsey263 03-25-2012 01:45 PM

Help! No Spark
 
I am restoring a 80 TA with 301 Turbo. I am not getting any spark to the plugs. I am getting 12 volts to the coil when the ignition switch is turned on. I have replaced the ignition coil, rotor and distributor cap. I have done a resistance test on the pick up coil (I think I did it correctly). I have swapped out the distributor module with another one, can't say for certain that it is good but I would think the likely hood that both of them being bad with the same exact results are remote.

Any Help would be greatly appreciated!!!

LATECH 03-25-2012 01:57 PM

2 Attachment(s)
The chances of both modules being bad are better than small.
If you painted the motor up nice, the distributor may not be getting a good ground.Try cleaning the paint off the contact spot for the hold down to the distributor and the bolt to the block to see, or check it with a test light to see if it is grounded well.Hook the test light to the positive of the battery and then anywhere you touch the probe end will light if you have a good ground.
What was the resistance of the pickup coil? Also the little hook like piece needs to be bolted the coil or it wont be grounded.

Lramsey263 03-25-2012 02:59 PM

I tried your suggestion, cleaned the contact points for the distributor hold down and was able to get a good ground. The resistance is 785 to 800 on the pick up coil.

lmsport 03-25-2012 03:26 PM

Thats a good value for the pickup coil resistance.
Are you sure its getting 12V to the distributor when the key is in the crank position? You can always run a jumper to the distributor straight from the battery.

Lramsey263 03-25-2012 03:30 PM

Yes, I measured it with a voltmeter to the connector and also left the coil cover off the distributor cap and measured it at the connection on the coil itself.

lmsport 03-25-2012 03:40 PM

Quote:

Originally Posted by Lramsey263
Yes, I measured it with a voltmeter to the connector and also left the coil cover off the distributor cap and measured it at the connection on the coil itself.

You measured while the engine was cranking?

If you have voltage and a new coil, you must have a bad module. Or two.

LATECH 03-25-2012 03:41 PM

the pickup coil polarity could be backwards.try reversing the green and white wires at the module.
Different GM lines use a different coil magnetic polarity , necessitating the need to reverse the color/connector/pin posistion . a coil for chevy will be reverse of what a pontiac will be.

Lramsey263 03-25-2012 03:47 PM

No, I measured the volts while the ignition switch was in the run position, not while cranking it...would that make a difference? I never messed with the distributor so I can only assume the polarity on the pick up coil is correct. However, could the ignition coil be reversed? Would it make a difference?

lmsport 03-25-2012 03:56 PM

It might make a difference.
Without looking at a schematic, I cant tell you if the start source and run source of voltage are the same. Run a jumper to the coil hot and crank it.

I think if you have the correct pickup coil, the polarity is correct cause the connector tabs to the module are different sizes???
I havent loooked at a stock HEI in a few years so pardon my memory.

Lramsey263 03-25-2012 04:01 PM

I will give that a try, if I run the jumper from the + Battery, can I also run a jumper from the - Battery to the other side of the coil to ensure I do have a good ground?
I appreciate your help!

lmsport 03-25-2012 04:12 PM

No, you can not ground the coil - as you for sure wont get any sparks.
You can run a ground jumper from the distributor body to the engine or the battery.
Measure the resistance of the dist body to the engine and make sure it is less than 1 ohm, preferably less than 0.1 ohm.

LATECH 03-25-2012 06:47 PM

Quote:

Originally Posted by Lramsey263
No, I measured the volts while the ignition switch was in the run position, not while cranking it...would that make a difference?
I never messed with the distributor so I can only assume the polarity on the pick up coil is correct. However, could the ignition coil be reversed? Would it make a difference?

Battery positive is from the same tab on the ignition switch when cranking as it is in the run position on your car. But the switch could have an issue so it is best to check it while cranking.
Assuming the polarity is correct, saying you havent messed with the distributor, then saying you measured the resistance of the pickup coil is contradictory. Not trying to bust your chops, but you were in there at the pickup coil. Are you sure you put it back in the right position.Maybe the wire broke when you were finished checking it. maybe you should take a second look.
Reversing the ignition coil wires in the HEI cap would be an obvious mistake, you would have to be trying real hard to put them in backwards.Did you check the ground wire out of the coil and the ground strap like in the picture?
making assumptions about circuit conditions is not a good solid way to do a diagnostic. test it check it , be sure, dont assume. That wastes everyones time. Once again not bustin chops , just trying to reinforce good testing, which will yield good results.

LATECH 03-25-2012 06:54 PM

Quote:

Originally Posted by Lramsey263
I am restoring a 80 TA with 301 Turbo. I am not getting any spark to the plugs. I have replaced the ignition coil, rotor and distributor cap. I have done a resistance test on the pick up coil (I think I did it correctly).

Did you also look at the conductor for the bottom side of the coil, the little thing with the spring on it?
Also maybe it is making good spark and it is shorting through the rotor.Look for a bad spot under the tang of the rotor where the coil button touches it.
The system may be making spark and it is just not making it to the plugs.
For what its worth.

Lramsey263 03-27-2012 05:36 PM

OK, I rechecked everything and to my ability it appears to be as I previously stated. What does this mean to me? When I hook a wire directly to the coil, I can get a spark when I touch ground, when I put a spark plug wire in seris with this setup, I can not get a spark. I also used a coil wire off a 67 Mustang to make sure I didn't have a bad wire but still could not get a spark.

LATECH 03-27-2012 06:37 PM

the only thing left would be the ignition module, that is if you are certain the rest of the components are good.
NAPA should be able to test the module, take them both down there and see.


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