No Spark, No clue...

[Ricko1966]

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

Yes it is. With a test light not a meter. The light will blink as the engine turns you are reading the tach pulse. This will tell you that the distributor is or is not signaling the module.

 

[tadslc]

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

You sure? Not to dispute you but seemed legit going by the trouble shooting section for the ESC in the factory manual. I don't have the exact procedures in front of me now and my memory is a little weak. I'll double check when I get back to the homestead.

Didn't go any further since it says to then use the factory ST-125 tool which I don't have and haven't researched it yet.

Thanks,

 

[tadslc]

While looking up info on the ST-125 spark tester, I came across this article. Looks pretty interesting, I'll read it all later. doesn't really cover my distributor but interesting anyway.

https://www.gmcmi.com/wp-content/uploads/2014/05/HEI-Testing.pdf

 

[Snoots]

The way I read it; it was a constant 12 volts. That's why I said it was wrong.

 

[Goldie Driver]

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/...ZKzDAbzNZKawVKj9Kt1w6BDtA8wtoPdWfmSdk7UUmZYC9

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.

That's a steal since a module alone is 35 bux or so !

 

[80BrownK10]

That's a steal since a module alone is 35 bux or so !

And the cap and rotor is probably going to cost you another $25 from a place like Rock Auto... probably more at a local store

 

[Ricko1966]

So the only thing I can figure is these guys are spending 100+ dollars in parts to build distributors to sell at a loss. Just because they are good guys, and they like us. Or they are using cheap parts to build a cheap distributor.

I don't think an aftermarket generic distributor is a good option for the O.P. 305 ESC engine anyways. More than likely it's only got 18 degrees built in so he will have to run 18 initial, the ESC 305s are ping monsters anyway. That's why they have ESC. So he's going to have to pull a bunch of initial out so it doesn't ping, now it's going to be a dog, never reach optimal total and never get the MPG it should.

 

[idahovette]

So the only thing I can figure is these guys are spending 100+ dollars in parts to build distributors to sell at a loss. Just because they are good guys, and the like us. Or they are using cheap parts to build a cheap distributor.

RIGHT!!!!..........really?

 

[Snoots]

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[Rusty Nail]

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

Actions speak louder than words - especially when you can't talk!

 

[tadslc]

Well still no closer to a solution than I started this morning. I feel like an idiot but I know I am not, having wrenched on cars for over 40 years. I studied the service manual for several hours last night and despite the poor printing and feeble wiring diagrams figured I had a pretty good handle on what wires I should be looking for. I've studied everything I could find posted on here and other places but alas, no luck.

Never could find the ESC controller under the dash either.

From what I could measure I'm convinced my coil and ignition module are working as they should. I've cleaned every ground and connector I could find.

Perhaps its time to purchase another distributor?


Haven't given up, just regrouping and doing more research.

Thanks,

 

[Ricko1966]

Did you do the esc bypass by shorting 2 wires leaving the other 2 still in the circuit? After this did you try to pulse the ignition with a soldering iron? It's been along time ago that I was in HEI class at GM and I only remember 4 wire modules. But if I'm remembering correctly you could take the 2 wires that went to the pickup coil off the module lick your finger touch the 2 module terminals and induce a spark on the secondary side.At this point on the game I would be licking my finger and triggering the module. Still no spark I'd do esc bypass and lick my finger and touch the modules.still no spark I'd test the coil if it tested good I'd put a module in it.If you get a different diff get a good used. O.E. 4pin HEI that way youcan swap your weights, springs, cam, and vacuum advance from your distributor to the replacement, so you still have a relatively stock advance curve.

 

[Bextreme04]

So the only thing I can figure is these guys are spending 100+ dollars in parts to build distributors to sell at a loss. Just because they are good guys, and they like us. Or they are using cheap parts to build a cheap distributor.

I don't think an aftermarket generic distributor is a good option for the O.P. 305 ESC engine anyways. More than likely it's only got 18 degrees built in so he will have to run 18 initial, the ESC 305s are ping monsters anyway. That's why they have ESC. So he's going to have to pull a bunch of initial out so it doesn't ping, now it's going to be a dog, never reach optimal total and never get the MPG it should.

Thats the only thing I’ve ever seen anyone knock the speed master distributors for... “they are cheap, therefore they must suck”. All the reviews amd anyone I’ve ever seen that has bought one has never had a problem. The one I got from skip white runs way better than the factory HEI it replaced that was old and loose. The adjustable vacuum advance was an especially nice feature and let me dial in my initial and cruise timing very well. Since he has spent days trying to hunt down a no spark condition, and his next step is probably going to be throwing parts at it, I was merely suggesting he use a cheap all in one solution that would get his truck on the road. It’s not ideal, and probably won’t let the truck run as well as the fully functional original equipment would... but since his current situation is not running at all, running seemed like a much better situation.

Ultimately my mechanic background cringes at throwing parts at it... but my practical side says if you don’t have the skills to isolate the actual issue, at least rule as many parts out as possible with the least amount of cost

 

[Ricko1966]

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Well I went to the jegs website in their reviews 7 people gave it a great rating 4 said it was total junk 1 bad new from the box 1 failed in like 20 miles I don't remember the others. I do not know if GM weights and cams will work in these distributors. Mostly what my point is if it costs 130.00 to buy the pieces to go through a distributor with good parts,how can someone build the entire thing new with quality parts sell it for 1/2 that and still make a profit. It just doesn't add up.And judging from the jegs reviews you have a better than 50/50 chance of being happy. I personally would fix my O.E. distributor or source a good used O.E. distributor.And an adjustable vacuum advance does not help you dial in initial timing.Initial plus centrifugal need to equal right around 36. The vacuum advance comes in on top of that to get you around 48 degrees .

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[Ricko1966]

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I used to fall for the appeal of cheap parts until I got burned a few times.True story,I got married in Eureeka Springs Arkansas. Did plugs cap rotor and module for the trip down,spent the night at a hotel next morning dressed in a suit to get married. Car would not start, cheap module failed. I changed it out in the parking lot in a suit,I still made it to my wedding on time but the pic of my wife's hand and mine at the wedding is comical ,fitting, but comical.