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No spark, need suggestions


kudu

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23 minutes ago, datzenmike said:

Well from the information supplied Positive is 10 v on the positive terminal then the coil is bad. Check the positive terminal once more for voltage with ignition on.

 

If you have 10-12 v then replace the coil.

still same result and i double checked and the hei is confirmed grounded. with ignition on the coil is read ~11 v similar to the “old” one. I feel like it would have to be distributor then no? granted the hei wires are no fully secured down as if it were final since i’m testing but I would think it should work as intended(the hei).

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2 minutes ago, datzenmike said:

Well we are moving in the right direction.

 

Re-check the HEI wiring on more time.

 

Only thing left is the trigger pulse from the pick up coil. You have a spare distributor? Put that one in.

what’s a trigger pulse again? I can’t quite remember

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33 minutes ago, datzenmike said:

The distributor spins a 4 pole magnet past a stationery coil. A very small electric pulse is generated. This pulse on the red/green wire triggers the HEI to ground the coil and then break the connection... same as with that jumper wire to ground.

same result as before. and again i flipped the red and green wires and no difference. My only concern about this distributor is that it’s slightly longer by a few millimeters so I don’t know how much that would change. It’s still grounded and still turns the rotor over but I’m not too sure what to try next.

I can give distributor numbers if that helps at all.

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Two distributors (no change) pretty much eliminates them as the problem.

InDpDXk.jpg

 

Are the coil terminals marked + and - ???

12v on the + terminal and the B on the HEI ???

 

How have you grounded the HEI???

 

 

Bare with me here. Use a battery jumper cable and connect the engine block metal to the body sheet metal. Does that help???

 

 

 

 

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are you seeing SPARK from the centor coil wire out of the coil??  this eliminate you putting the plug wires on wrong or dist out 180 if you looking for spark out of a plug wire in case you got the timing wrong.

checking from the center shows the dist signal and coil power is working.. if dist swap then no change then it has to be the coil power or coil

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18 hours ago, datzenmike said:

Two distributors (no change) pretty much eliminates them as the problem.

InDpDXk.jpg

 

Are the coil terminals marked + and - ???

12v on the + terminal and the B on the HEI ???

 

How have you grounded the HEI???

 

 

Bare with me here. Use a battery jumper cable and connect the engine block metal to the body sheet metal. Does that help???

 

 

 

 

so i remembered my power probe from work and i just double checked everything and realized my negative side of the coil currently has 12.4 b, same as the positive side. the HEI is grounded by being bolted to a piece of aluminum that is then bolted to the body and does have ground confirmed. Yes the coil is marked - and +. Terminal B has 12.4 v. There was a wire coming off of the - going to the chassis but didn’t see any pictures of anyone else having one so i removed it just to give as much info as possible.

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9 hours ago, banzai510(hainz) said:

are you seeing SPARK from the centor coil wire out of the coil??  this eliminate you putting the plug wires on wrong or dist out 180 if you looking for spark out of a plug wire in case you got the timing wrong.

checking from the center shows the dist signal and coil power is working.. if dist swap then no change then it has to be the coil power or coil

How do you go about checking for spark from the center coil wire?

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Welp don’t ask me how but the truck is running. Literally I changed nothing from what I left it as last night and was just testing a ton of things and had a friend crank the motor over while I tested spark from the coil having the center wire slightly away from it. And boom the truck starts up

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52 minutes ago, kudu said:

so i remembered my power probe from work and i just double checked everything and realized my negative side of the coil currently has 12.4 b, same as the positive side.

 

The negative side of the coil is not grounded until the HEI module does so. The voltage reading is simply power through the coil from the positive side. Normal.

 

52 minutes ago, kudu said:

 There was a wire coming off of the - going to the chassis but didn’t see any pictures of anyone else having one so i removed it just to give as much info as possible.

 

No no no. There has to be a ground to the body sheet metal. If not there make one. The negative battery cable bolts to the head so the

block is grounded. Run a 10 gauge wire from anywhere on the block to any where on the body metal. 

 


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33 minutes ago, kudu said:

Thank you both so much for your help these last few days I never would have been able to do this without you guys. Now i’ll just solder everything up, make some looms and go enjoy this truck. Again thank you guys so much

 

Glad you got her running.

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On 10/14/2021 at 7:49 PM, datzenmike said:

 

Glad you got her running.

welp sadly i spoke too soon. She started up fine and i started to go up the driveway and realized my headlights weren’t working so i stopped at the top of the driveway to fix that. Go to start it and no spark again. nothing coming from the coil

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1 hour ago, datzenmike said:

Obviously it works. Must be something lose.

 

Did you get a ground to the body?

yeah i grounded the valve cover to the firewall. All of the connections i made were soldered and secured to their specific places. So I wouldn’t think it would be on my end. The coil and HEI are getting 12+ volts, the hei is still grounded

 

Could it be ignition switch related? or is that not how these trucks do it

 

none of the wires seem messed up and all of the plugs looked good. I unplugged them and looked for corrosion and there wasn’t any apart from the ignition switch had some but i cleaned that off. All of the plugs seemed secure but i unplugged and plugged them all back in

 

Not sure if this has anything to do with anything but i thought i may mention and i just remember that this was a california truck so it had the california emissions that have been delete from it but that was 8 months ago done by the previous owner

Edited by kudu
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6 hours ago, datzenmike said:

Try starting. Maybe the coil heats up and fails, cools down and works.

yep you’re completely right. Thy explains why it randomly started with no changed because it was the first time trying to start it that day. So am I just forced to carry around a spare coil with me everywhere i go(which i have but a little annoying)

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A random problem is the worst thing to try and fix. Do you have a spare coil? Just replace it and see if the problem goes away. If not, DON'T run out and buy one. Next time it quits pour ice cold water over the coil body to cool it. If in 10 min it starts you have confirmation.

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