No Spark, No clue...

[80BrownK10]

Put a test light on the tach terminal of the distributor. Turn the key on, the test light should light up. If not, either you don’t have power to the coil, or the new coil is defective.

Crank the engine, does the test light flicker? If not, the coil isn’t being triggered. You could have a defective ignition module, bad pickup coil, or mechanical failure (timing chain, worn cam/distributor gears, etc).

If you have replaced the coil and module, inspect the pickup coil wires. I bet you find one either broken, or just barely hanging on by a single strand of copper wire. No signal from the pickup coil to the module, no spark.

Good call, not sure anyone mentioned that yet. Timing chain could of been streched, jumped time, worn gears...did these have the nylon ones originally...maybe never swapped and it jumped? If timing doesn't add up may need to pull the front of that motor apart....but confirm everything thing else before you do this.

 

[80BrownK10]

Did we ask this? You sure it's not 180 out? You have been pulling distributors.

 

[75Monza]

Did we ask this? You sure it's not 180 out? You have been pulling distributors.

Doubtful, since no spark at plug stated. Maybe truck wants a big block?

 

[tadslc]

Not what I meant, do the bypass as directed but instead of cutting the wires which you don't want to do unplug the dizzy, make 4 jumper wires. Do the bypass on the jumper wires just like you would on original harness, then post results back.

I thought I did this last evening when I jumpered the black and green wires coming from the distributor after unplugging the 4-wire harness to the ESC. I didn't do anything with the actual ESC unit itself behind the glovebox.

 

[tadslc]

Totally out there question, but does the distributor actually turn when motor cranked?

Rotor turns nicely

 

[tadslc]

Put a test light on the tach terminal of the distributor. Turn the key on, the test light should light up. If not, either you don’t have power to the coil, or the new coil is defective.

Crank the engine, does the test light flicker? If not, the coil isn’t being triggered. You could have a defective ignition module, bad pickup coil, or mechanical failure (timing chain, worn cam/distributor gears, etc).

If you have replaced the coil and module, inspect the pickup coil wires. I bet you find one either broken, or just barely hanging on by a single strand of copper wire. No signal from the pickup coil to the module, no spark.

I did put a voltmeter on the Tach terminal and got 12 volts when the ignition was on, didn't notice any fluctuation when cranking but I wasn't really looking for it. I'll try thing test again as well.

Thanks to all

 

[75Monza]

Here is a decent test sheet for HEI if it helps. https://www.gmcmi.com/wp-content/uploads/2014/05/HEI-Testing.pdf
Didn't see a mention, but did you check the carbon button in the cap? I've had that fall out before after a coil change, never did figure out why, just installed another one and was fine. Also had where bad contact from button to bottom of coil and ended up arcing there so no contact after that either.

 

[Ricko1966]

I thought I did this last evening when I jumpered the black and green wires coming from the distributor after unplugging the 4-wire harness to the ESC. I didn't do anything with the actual ESC unit itself behind the glovebox.

I don't know what you did last night you said you jumpered green and black but jumpering then and still leaving them connected to the harness still has them in the esc circuit. So what I'm saying now is make a four wire jumper harness treat your 4 wire jumper harness exactly like it was the actual distributor harness and perform the bypass there.So the black and green in your jumper will be cut stripped and twisted. The other wires are still intact via jumpers to their original positions.Then if the truck starts we know it's in the esc circuit.

 

[Matt69olds]

I did put a voltmeter on the Tach terminal and got 12 volts when the ignition was on, didn't notice any fluctuation when cranking but I wasn't really looking for it. I'll try thing test again as well.

Thanks to all

You will never see a voltmeter change, the pulses will be too fast. Get a cheap test light

 

[Ricko1966]

thanks guys

I tried to jumper the black and green wire from the ESC and still have a no start problem. Not ready to cut them yet...

Anyone ever replace the condenser?

This is the info I was looking at as to how you did the esc bypass. IDK what you did for sure. Matt said check power and pulse with a test light at the tech terminal. Good advice but it gas to be done with a light not a meter.

 

[Ricko1966]

You will never see a voltmeter change, the pulses will be too fast. Get a cheap test light

Looks like you and I were typing at the same time

 

[El Perdido]

In the 27 years I have owned my '85 K20 Suburban, it has "stopped" two times just as you describe and it has been the module on both occasions.

You having replaced yours leaves me flummoxed.

 

[Bextreme04]

Personally, I’d just get a skip white HEI distributor without ESC and call it a day. It’s $54 shipped to your door. I’ve got one in my 1980 K25 and it works great.

I guess you can’t order it through skip white anymore, but it is basically the speed master setup that you can now order through Jegs here:https://www.jegs.com/i/Speedmaster/746/PCE376103201/10002/-1?gclid=Cj0KCQiA3smABhCjARIsAKtrg6JH6fDiZgtmqJVxetf0M2uGnYWy6o54jWt0E3YcxERpRCc9xEhsPC0aAuHTEALw_wcB&__cf_chl_jschl_tk__=6716ff3eb7ee13e2b8e78efe9190d944c141a2b9-1611896944-0-AUrXunp5Ua2XSIWKLTFNMuvYfpCwEo9uxXoZh4owK-_OF2j9R8MtiTgo1kwGgZGtbZ-l9wbDeEK6SXcD9MhFoxLBxjBIKE0qb9oB4sBbAeCupUNyowPxJ_gHThOEVTm3Y9uT0vypjoHRpN1y0MvD6KxQdg6xPvO67sYfGXqxK9HgELpX1qHJUHi7Xbi-gG5hTVy3E_z7FKx2Jt0cfjeTrVB3cSy2VmeDKPYSAC80kQQxYeivIxlGRxGY3TbJp6_86ykddb1oL2N2VHhOPEIZaqBeCk4lJBWyBCJCNy2SaD6-yABsdvtXFPDo2fHH4_Ab8_mVW17zsIX0zMcgATeNh009jCb7QSA2DxaknU64LhNldCSryaZhtGu7QmePVouVgyFJIuyagNk48JKsph3to-t90crgXyoERSG8Y5uIqd7WRMK2cUwhFSDiimpLRpxZKzDAbzNZKawVKj9Kt1w6BDtA8wtoPdWfmSdk7UUmZYC9

The vacuum advance can be a bit aggressive.. thankfully it’s adjustable so you can really dial it in well with the initial advance and vacuum.

 

[tadslc]

Didn't get a chance to look any further last evening. I guess this will be a weekend project.

 

[Snoots]

I did put a voltmeter on the Tach terminal and got 12 volts when the ignition was on, didn't notice any fluctuation when cranking but I wasn't really looking for it. I'll try thing test again as well.

Thanks to all

12 volts on the TACH terminal!?
That ain't right!