Brief story. Car just was cammed. Since the cam i have been having serious miss-fires within the ignition system.

Sorry for this long post but i have had it!

A friend suggested getting a MSD box (i did 6al), and some new plugs, which i did to help with "tip in" as he called it of the throttle. ( ie getting started at a light and low rpm).

Before installing the new plugs, i threw the box on the car, not mounting it or anything, over by the battery. I used the battery pos distribution block for power, and the grounding stud right by it for the ground. With the old plugs (ac plats) i took the car for a quick 2 min spin and it ran awesome.

Came home and started on the splugs, and moved the MSD box to its permanent home over by the air filter. I ran the positive to the same spot as before, and grounded it on the frame. Changed to TR55 plugs from the AC delco plats. I gapped the TR55 plugs at .050. Started car up and it ran horrible, worse than ever. Missing and bogging at low rpm.

Some suggested the .050 gap was too large for my application. I dont know why, but i listened to them. They suggested lower gaps on the plugs, so i went back in and re-gapped all the plugs to .037. This was time #2 for plugs. Anyone with a LT1 knows this is a project and 1/2. I figured the nitrous guys were running small gaps like that NA so if i had a weak spark it should help. I also took the ground wire from the box, and moved it back over to the main stud by the battery.

Now the car drives worse than ever before. It backfires at anything under 2k rpm with a decent MAP load.

Im lost on what to do. I have two options i guess. Go back and re-install the delco plats which looked ok and are low miles. The box when in its temporary position with these plugs ran great. Second option is to shorten the ground wire for the box. Maybe it is having issues. I used a bigger gauge wire to ground it to the stud, but i maybe that isnt good enough. Whats the ideal spot to ground the box when it is installed by the airfilter. I think there is a grounding stud directly to the right and below the coil mounted on the head.

Any and all opinions are more than welcome. Once again sorry for the long post. Also before you all say it, the wires are on the correct cyl. I have checked that 50,000 times.

 

Almost been one day, this is my only TTT

 

did you check the dowl pin length on the cam before you installed it to make sure its not too long? a long pin will break optis.

 

Yes i measured it with a caliper. I dont remember the measurement number that i used, but it came from Fred (injuneer) so i trust that it was correct. His number was nails on the number that i measured on the cam as it came from Crane. It was the longer dowel for 95+ opti.

Very good suggestion/guess however, it is appriciated.

 

I'm going with cam timing. I'll bet it's off.

 

slopoke is right it's your cam timing!

 

Meaning i didnt install it correctly or it was ground wrong?

I dont see how I could have messed it up when installing it straight up but who knows,

Also, if their are any data experts out there, i have logs in TTS and freeScan if anyone wants to look them over.

 

well if you said that it was running great until you did the plugs and the msd, so your problem is there unless you jumped a tooth on the timing gears. I wouldnt worry about that much if you did a new cam and timing chain

 

Problem fixed!!!!

Bought a new set of plugs and ran them at .045. Car runs great! Guess i got a bad set of plugs first time around. Back they go to NGK.

Thanks for all your help!