I was working on the pickup that I put an engine in for Andrew Shank. It ran really nice, and he had left it parked at my house for the last couple months. I went out to start it to move it and it would not start. Spark looked really weak and it was jumping fire out the side of the tower. I put the coil off my truck on to it and it fired right up and sounded fine. So I ordered a Petronix flamethrower and installed it and it will start but as soon as the rpm comes down from about 2500 it sounds like it is running on 4 cylinders and shuts off. I did not have time to look at anything other than to check the plug wires are on right. But I am wondering if I got the wrong coil. I got the 3.0 ohm one instead of the 1.5 ohm one. Could that be the issue? Or do I look elsewhere? It does have the HEI on it and those wires are installed correctly too.

Thanks, Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I use the 3 ohm coil and it works perfectly.


Did you make sure to remove and/or bypass the ballast resistor?



I'm use the pertronix 1 ignitor.


3.0 might be too much resistance for a HEI



With HEI, I think you can go to a 0.7

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

This is on an 85 truck so it did not have a ballast resistor.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

This truck runs fine with the coil from your truck? Is that still true? If so I'd go get an HEI type coil and install it along with the appropriate coil wire.

If this is not the case then...

If it's working at high RPM I would start look at reluctor air gap. Also, how are the tune-up parts like cap and rotor? How is the rotor phasing? What is the voltage at the coil/HEI module?

Ideally you'd want an HEI type of coil for peak performance, but a 3 ohm coil shouldn't cause the problems you're experiencing, but I can't rule it out either.

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Joshua

Haven't touched it since I posted last, but I will look at it tomorrow evening and see. The coil off of my truck was a standard factory coil that was on my 85 when I swapped out the Lean burn. I'll check the voltages and air gap and report back.

Thanks

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Jumped my coil back onto Andrew's truck, and it fired up and runs fine and idles fine too. Voltage at the HEI module/coil is 13.8V and 14.1V at the battery at idle. Petronix is headed back for a refund.

Thanks, guys!

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Thank you for the update. These days I prefer good used OEM over new Chinese parts in a lot of instances. If you're not married to a canister coil I will repeat my suggestion of a GM HEI coil or a Ford TFI coil.

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Joshua