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Discussion Starter #1
All right... I'm not getting any spark from my HEI. I made sure the distributor is getting 12volts. I even tried running a wire directly from the battery, but still nothing. I replaced the control module and that didn't work either. My next guess is the coil. Is there anyway to check it to see if it's good? I don't want to run out and buy a new one if I don't have to. Thanks.
 

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take a test light and hook it to 12v pos and touch the green wire on the module and that should fire the coil. be careful because if the coil is good it will jump fire and get something like your hand..

Mitch


orange'66 said:
All right... I'm not getting any spark from my HEI. I made sure the distributor is getting 12volts. I even tried running a wire directly from the battery, but still nothing. I replaced the control module and that didn't work either. My next guess is the coil. Is there anyway to check it to see if it's good? I don't want to run out and buy a new one if I don't have to. Thanks.
 

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Discussion Starter #4
I Have another car with an HEI so I took the cap/coil off of that one and put it on the Nova. Still nothing. Oh yeah...When I had the HEI out of the car the other day I checked the roll pin. it was good. Could this be some sort of ground issue? I'm out of guesses.
 

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Greetings,

Check the control module as well...If it's bad it won't allow the HEI to fire as well.

Jason
 

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Pickup?

you may as a last resort try replacing the pickup,really an easy job once you have done one or two,its rare that it goes bad but i have had it happen to me before,hope you have some better luck.:D

66-Deuce
 

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This will sound way too simple, but take the rotor from the running car and put it in the non-running car. I've experienced it many times--under the metal contact a tiny hole will burn and cause the spark to jump where it should not be. Won't cost anything to try.
 

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Discussion Starter #8
Thanks guys. I'll try swapping the rotor tommorrow. If that doesn't work I'll check out the pick up.
Now that I think of it, the last time I had a timing light on the engine, which was right before it stopped working, The timing was very erratic. It was jumpimg all over the place. So maybe it is the pickup.
 

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bowtie0069 said:
This will sound way too simple, but take the rotor from the running car and put it in the non-running car. I've experienced it many times--under the metal contact a tiny hole will burn and cause the spark to jump where it should not be. Won't cost anything to try.
Very commom in this distributor!
 

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99% of the time the pickup coil has a broken wire. Just lightly grab the 2 wires and see if either of them become or are disconnected.
 
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First, confirm battery voltage at the BATT term on the HEI in BOTH key positions, run and start. HEI has to have voltage in both.

Tachometer to TACH term?, remove the wire and check for spark, no spark, below.

If you have an Zuto Zone atore or other one that has a checking machine, take the coil to the store and have it load tested. they can also test the modules for failure OFF the engine. Their Wells line of modules is good, actually the same as OEM GM modules, and are warrenteed for life.

Also, there are two grounding parts for the coil. These in cap coils need to be grounded, which they do through the center wire of the three wire connector from the body to the coil. What you will also find is a ring terminal and wire from the coil that is connected to one of the coil holddown screws, these get dirty and lost connectivity. There is also a ground bar UNDER the coil, runs the grounding from the coil to the three prong connector for grounding, can get corroded, dirty, and stop the spark.

Also, the carbon brush can go bad, test for resistance, post result here. There is only ONE way to goes into the cap, brush down through the hole, spring end upwards, then, the insulator donut, use silicone grease to seal it to the cap and coil, then the coil. If the brush is installed above the donut, then a gap is created between the rotor bar and brush, causing the coil to be way, way overworked and overloaded, with imminent failure to follow not far after.

Magnetic pickup, check the ohms resistance and post here, shouild be between 500 and 800 ohms. When you test the resistance, move the wires around to check for breaks in the wires, which is a fairly common issue with HEI, along with the junker in cap coils going heat ballistic and melting themselves from the inside out. When this happens, module after module after module failing is a dead giveaway that the large cap garbage coil is dieing/dead.
 

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Discussion Starter #12
...Swapped rotors after work, checked the wires going to the pickup, made sure the ground wire was there and intact. Still nothing.
Next I popped the brush out of the cap and checked for resistance between the brush tip and the end of the spring. That was good too. And it was installed correctly.
Ignition man, If you meant to check pickup resistance between the pickup and the two wires that connect to the module, then they are good. They were around 600 OHMs.
I'm starting to think that I'm missing something really obvious and stupid, but I just can't figure it out.
 

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If you have a tach and it's bad it could short the tach lead causing no spark. nplug the tach wire and try and spin'er up.
 

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You might of got a bad control module from the parts store I have seen this before I would try another one. Put the dielectric grease on the bottom side before your install.
 

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how are you checking for spark? maybe you are getting spark but not grounding properly while you check. happened to me once, pain in my a$$. I pulled a spark plug and wire and touched it to the block. nothing. I checked all the same stuff you did only to realize i was out of gas. IDIOT!!!:mad:
 
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Pickup resistwance is measured between both wires and from each wire to ground. Your 600 ohms would indicate the pickup was OK, but do check each wire to the dist body ground and see if you get any resistance. Shouldn't be any, open between each wire and ground.

If your mete4r is a digital readout one, put both wires from it together, and read the resistance the meter uses. Consider this resistance moot, it will add itself to any reading, just subtract it from the reading to get the correct value.

I think you have already tried this, but might again, run a jumper wire from the positive side of the battery, or the large lug on the rear of the alternator, to the BATT term on the cap, and try for spark.
 

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Discussion Starter #17
When I checked resistance between the distributor body and each pickup wire, there is some resistance. What does that mean and what can I do about it?
I've been checking for spark by hooking a timing light to the #1 plug wire. I tried running a wire directly from the battery to the distributor again yesterday to double check myself, but it didn't help.
 
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As I outlined previously, connect the two wires from the meter together, and read the resistance the meter uses to operate.

Now, connect each wire to ground and see if that same resistance comes up. If so, consider the pickup ungrounded. If the resistance is more than the meter uses, pickup needs replacement.
 
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