[L78toLT1]

Hey guys, can one of the elder statesmen here help me to troubleshoot an issue with my car? I just finished reassembling my motor after dropping a valve at Road Atlanta a while back. I trashed the block, one head, and the blower.
I built the short block back, same as before, picked up some CID heads with LT4 intakes and inconel exhaust valves, and had the blower rebuilt by Superchargers online. I also swapped in a Cammotion pd blower cam. I was on my 2nd or third iteration of remote tuning with Ted J when the motor developed a miss at the top of my first WOT log - Ted's out of the office until Monday so I can't pick his brain until he returns. It's apparent that the motor is running on seven cylinders. I'll check the plugs, wires etc. If I'm lucky, it will be ignition related. I'm really hoping it's not an injector, even though I've had the blower off so many times I could do it blindfolded lol!
What confuses me is that it didn't throw a cel. I drove at least ten miles back home after the miss appeared, still no light. Shouldn't a dead cylinder, regardless of the cause throw a cel? High and low
side pressures, pulse width are fine, there was no knock retard. I'm confident as is Ted that it's not a lean condition. Any ideas? I'm planning to start troubleshooting in the morning.

[laynlo15]

Which cylinder is dead? It could be an ignition coil? Spark Plug wire or maybe you broke the porcelain on one of the plugs when you installed them. Thats pretty easy to do. I'm thinking its ignition related.

[L78toLT1]

Originally Posted by laynlo15

Which cylinder is dead? It could be an ignition coil? Spark Plug wire or maybe you broke the porcelain on one of the plugs when you installed them. Thats pretty easy to do. I'm thinking its ignition related.

That's certainly what I'm thinking too, Greg. I'm going to check the plugs, wires, etc. Don't think I cracked a plug as the motor probably had 100 or so miles on it before it started missing. What confuses me is the no cel situation. Wouldn't just about anything ignition related throw a code?

[L78toLT1]

Originally Posted by laynlo15

Which cylinder is dead? It could be an ignition coil? Spark Plug wire or maybe you broke the porcelain on one of the plugs when you installed them. Thats pretty easy to do. I'm thinking its ignition related.

That's certainly what I'm thinking too, Greg. I'm going to check the plugs, wires, etc. Don't think I cracked a plug as the motor probably had 100 or so miles on it before it started missing. What confuses me is the no cel situation. Wouldn't just about anything ignition related throw a code?

[L78toLT1]

Sorry for the double post...

[laynlo15]

Originally Posted by L78toLT1

That's certainly what I'm thinking too, Greg. I'm going to check the plugs, wires, etc. Don't think I cracked a plug as the motor probably had 100 or so miles on it before it started missing. What confuses me is the no cel situation. Wouldn't just about anything ignition related throw a code?

I don't think so, when I built the Manley Forged motor we put it back in the car and was putting some miles on it and it had a miss but couldn't figure it out. We went ahead to the dyno and on the pulls it would start the same miss again and my buddy Matt said he thought it might be a plug wire, so he pulled the one he thought it was and sure enough it was one of the wires I'd run the year before. The dyno guy builds his own wire sets and Matt put together a new wire which happened to be the number 3 cylinder and that took care of it. But I never had a cel of any kind.

[L78toLT1]

It was cylinder #7. I dug out my old timing light and hooked it to the wires, one at a time and 7 was dead. I unplugged it, hit it with some contact cleaner and a dab of dielectric grease and it was good to go. Don't throw away those old timing lights, they're great for troubleshooting ignition issues.
I was confused about the cel, because when I was at the fest last year, I burnt a wire on the ncm road course and got a cel that decoded to "misfire on cylinder x" (can't remember which one it was). Maybe you have to run a good while with a miss before it will throw a code, but that doesn't sound right. I stayed on the track last year and read the code at the end of the session. Can't remember if the light came on immediately, or not.

[L78toLT1]

Last post isn't entirely clear: I unplugged the electric connector to the coil, not the plug wire.

[laynlo15]

So no dead soldier now?

[L78toLT1]

Originally Posted by laynlo15

So no dead soldier now?

Shit no, it's dead again! When I identified the bad cylinder, I pulled the coil off and cleaned the contacts on the coil and electrical connector on the harness side. I smeared on a little dielectric grease, plugged it up, and fired it up before I bolting the coil back down to see if it fixed the miss. It did, so I came in the house and ate lunch. Went out and bolted the coil down and it's missing again. No amount of wiggling the connector stopped the miss. I took the coil off again to inspect everything more closely, all looked good so I fired her up again without bolting down the coil. You guessed it, hitting on all 8, smooth as silk. The electrical plug looks good as new. I'm thinking the problem is with the harness. You can only see about two inches of the damn thing on #7 before it disappears behind the blower. Gonna be a hell of a note if I have to pull the blower for something like this!

[laynlo15]

Originally Posted by L78toLT1

Shit no, it's dead again! When I identified the bad cylinder, I pulled the coil off and cleaned the contacts on the coil and electrical connector on the harness side. I smeared on a little dielectric grease, plugged it up, and fired it up before I bolting the coil back down to see if it fixed the miss. It did, so I came in the house and ate lunch. Went out and bolted the coil down and it's missing again. No amount of wiggling the connector stopped the miss. I took the coil off again to inspect everything more closely, all looked good so I fired her up again without bolting down the coil. You guessed it, hitting on all 8, smooth as silk. The electrical plug looks good as new. I'm thinking the problem is with the harness. You can only see about two inches of the damn thing on #7 before it disappears behind the blower. Gonna be a hell of a note if I have to pull the blower for something like this!

Ok, so swap that coil with another just to verify your findings. Just take a couple minutes to do. Worth the time I'd say.

[L78toLT1]

Yeah, that's my next step. Hope it's the coil. I'd rather cough up thirty bucks than have to pull the blower to fix a wire

[laynlo15]

Originally Posted by L78toLT1

Yeah, that's my next step. Hope it's the coil. I'd rather cough up thirty bucks than have to pull the blower to fix a wire

Let me know how it works out. You should still have my phone number so you can always call or text

[L78toLT1]

Originally Posted by laynlo15

Let me know how it works out. You should still have my phone number so you can always call or text

Thanks, Greg!