No spark! Tried a new coil, still no spark

[buddy84GMC]

I have an 84 Sierra with a small block 400 in it with HEI.  It stopped running when it wanted to shift, but that had nothing to do with it when I pulled a spark plug wire and no spark.  I ran down to Advance and got a new coil and still no spark.  The old coil witch was really only 1,300 miles old had a scroched wire so I thought that was the problem.  Changed the coil and tried to wiggle all the wires connecting to the leads.  Nothing works.  I have to go back tomorrow and put a test light on it.  Any tips on what each side of the coil wires are?  The red I would imagine is the power source, and the yellow one, I have no clue.  If I hook the test light up to it, the red wire should be hot with the ignition turned on, but not cranking???  The yellow wire may become hot once it crank, but not sure.  I looked at the rotor as well and it looks fine.  Its new as well.  Thanks for any help. 

[Blue 82]

With the key on the red should be hot (even when not cranking, but the key must be in the "run" position)
Make sure the red on the coil lines up with the red in the module plug
the yellow is the ground

My 82 had the HEI with the ESC (electronic spaek control)
I converted it to the 3 wire normal HEI

You may have an issue with the Module or the ESC box or the condensor

[Lt.Del]

timing chain?

[Blue 82]

timing chain?

I had that happen once
pull the cap and turn the key to crank
no rotation from the rotor is a sure sign
but it may be a sheared gear pin

[buddy84GMC]

Good idea about the cranking with the cap off.  I will head back out there in the morning and give it a try and test the wires.  If all goes well and I figure it out...some neighbors are getting a wake up call!  I will post back what it was if I figure it out.  Any other pointers???  Thanks again

[VileZambonie]

If the engine sounds normal during cranking and you have B+ at the ignition coil then check the ignition module and the pick up coil. Disconnect the pigtail at the module and measure the resistance of the pick up coil. spec is 500-1500 Ω typically you'll find 800Ω on a good one. If the pick up coil is good replace the module.

[buddy84GMC]

I have done everything I can with the distributor on.  I got a new coil, had the control module checked and its good.  Cleaned up the plug prongs for the module and tried again..still no spark.  It could be the pick up wires under the distibutor.  I wiggled them and they seem to be in tact, but I was told they can break off under that plate I guess where the bearing is.  Thats where I am at right now.  Might have to get it towed and pull the distributor off and check the pick up wires.  Any other ideas would help since I am stumped, especially if those wires are good.  The rotor turns when cranked as well.  Thanks

[Blue 82]

I replaced my 25 year old HEI with one of these

http://cgi.ebay.com/ebaymotors/SBC-BBC-CHEVY-HEI-DISTRIBUTOR-RED-8908-R_W0QQcmdZViewItemQQcategoryZ33690QQihZ015QQitemZ250241458008

It took a little tuning to get it right (lighter advance springs etc...)

Been in the truck for 8 or 9 weeks now, so far so good

[buddy84GMC]

Thanks.  Not bad considering the coil I just bought cost just as much!  I would like to solve the problem first and find a reason to buy a new distributor.  Once I find the problem and if it needs replaced...I would go for that one too!  Thanks

[79scottsdale]

You talked about having the module checked, but did you ohm out your pickup coil? We just went through that with ours, and the pickup coil was bad. I decided to replace the distributor since it was 29 years old, and I figured that if I had to disassemble it to replace the coil, I'd just replace everything. Good luck!

[Blue 82]

Provided you have 12 vdc to the unit,
Theres only 4 or 5 things that can go wrong with the HEI (electrically)

1. coil
2. Module
3. condensor (you should change this when you change the module)
4. the coil under the reluctor (I just measured the resistance on a "known" good unit- 830 ohms at the module plug (unplugged))
5. ESC box (on Electronic spark controlled trucks)
(I have no clue how to check the ESC box)

Do you have the ESX box?

[Fordeatinz71]

how many times did they check the ignition module?  sometimes you have to check it repeatedly to make it fail.  gotta get it good and hot.  anyhow, if your pick-up coil tests good, you probably need to just bypass the ESC...good luck

[buddy84GMC]

Not too sure if I have an ESC but I saw the condenser and that can be replaced for $5.  All I can say about the ESC is that my truck has a double plug in piggyback to the one that goes into the control module.  I do not know if that could be the ESC??  The control module was tested 3 times in a row and passed all 3.  They did say they needed to do it a few times to let it warm up.  If the ESC is a box...I didnt see it in there.  Thanks

[Fordeatinz71]

an ESC module looks like this and can be found on the firewall somewhere near the distributor...

[buddy84GMC]

Great.  Thanks a lot.  I will yank that off too and see if I can get it checked at Advanced.  Is there any chance that the control module can test ok, but not work when on the truck?  I am tempted to buy one and try anyways.  One last try on before I have to take the distributor out and check the pick up wires to see if they snapped off.