Ignition Issue, NON TURBO RELATED

[Yedi]

Just so I don't get slammed, this is a technical ignition question that is NON TURBO related..

350 Chevy crate motor, HEI Distributor, ran perfect before install of Summit Digital CDI Box, and MSD Super conductor wires.

I installed a Summit Digital CDI Ignition box, followed instructions to a T installed new MSD Super conductor Wires, car runs good..BUT..under load when the torque converter is locked up it has a miss, I know this is electrical because when it misses the Tach needle jumps around (more than what the motor is actually doing)

I called Summit and they had no idea, just said "make sure cylinder 5 and 7 wires arent touching" I told him their brand new wires, I did this and it's the same.

Any ideas?? It's grounded right to the battery and I hooked everything else up as instructions said.

Let me know, My only other Idea is to check Spark Plugs?? LIke I said, it runs perfect except when under load, TC Locked up you notice it....

 

[87NAT]

You dont need to check spark plugs, you need to check the parts you changed.

Put the old wires back on and see it still misses. If so, its not the wires. Put your old HEI back on and see if it misses. If it clears up you know its the MSD box. Simple enough:smile:

 

[mikestertwo]

I assume you are using the magnetic trigger in the HEI distributor. Try reversing the two trigger lines and see what happens.

 

[Yedi]

So I'm in the middle of diagnosing this problem, I'm starting w/ the basics first, the spark plugs, I checked the Left bank, all were fine. I get to the Right bank, and on plug #6, I find it only finger tight, I took it out w/ no tools. Could this be a possible issue w/ the miss??

I'm going to redo a ground wire that goes to the dist, I never had one on there before installing the CDI box, then I'll test drive it and see what happens.

I forgot to mention that I didn't drive this car this year before all the mods were installed, so it's hard to just blame the wires/box.

You dont need to check spark plugs, you need to check the parts you changed.

Put the old wires back on and see it still misses. If so, its not the wires. Put your old HEI back on and see if it misses. If it clears up you know its the MSD box. Simple enough

not that simple man, all the wires, taking the distrib. apart swapping parts back in, I know what your saying though.

I assume you are using the magnetic trigger in the HEI distributor. Try reversing the two trigger lines and see what happens.

I'll double check the wires, I hooked them up exactly as described in the instructions, and it runs great, I just have a miss under load w/ TC locked up over 60mph.....I would like to think this would cause an issue al the time if the wires were backwards??