platinum plugs with weak spark

80goldenburb

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i have Bosch platinum iridium plugs that are supposed to be a bright bluish white. I have used these before in multiple 350 Vortec powered trucks, and previous Cadillac lowrider (with 8.2L 500ci). currently have the Cad 472 in my '80. HEI is from a 75 500 with all new guts. Battery cables are welding cables. What would make it have such a weak spark?
 

SirRobyn0

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To me weak spark is harder to troubleshoot than no spark, if it was me and I know my connections are all good, tight, wiring ok, and full 12 volts at distributor + connection, I would swap the coil with another unit if you have one. If that's not it I'd look at the pick up in the distributor. I know your parts are new, but as you know you can get a defect.
 

Bextreme04

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Make sure the coil feed is getting 12+ volts and the ground is good and clean on the coil as well.
 

80goldenburb

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I would swap the coil with another unit if you have one. If that's not it I'd look at the pick up in the distributor. I know your parts are new, but as you know you can get a defect.

yes i just put in anuther new coil. the one before was new from about 2 years ago, but the adhesive on it was broken up


Make sure the coil feed is getting 12+ volts and the ground is good and clean on the coil as well.

should i also consider tapping into the external ground wire (outside the cap) and run to another ground source? ive done that before to another truck that had unknown (and unsolved) ground issues with the HEI and surprisingly it fired up
 

SirRobyn0

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Removed what I wrote earlier in the realization it wasn't the best advice, sorry about that 80goldenburb, I totally misunderstood what you were asking about the ground.
 
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Bextreme04

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should i also consider tapping into the external ground wire (outside the cap) and run to another ground source? ive done that before to another truck that had unknown (and unsolved) ground issues with the HEI and surprisingly it fired up

I would at the very least unhook the three wire connector that runs to the distributor body and check continuity to the engine or battery ground. If you have a bunch of resistance, you probably have a bad ground somewhere.
 

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