Need help....
New 383 LT1 with hot cam kit, headers, ported heads, all forged bottom end, MadZ28 tune.
Barely broken in with 1500 miles.

Optispark just failed beacause of water pump leak due to bearing failure.
Ran great before opti failure.

Mechanic replaced opti with accel opti & new GM Water pump.

Now cyls 4&6 are dead but have good compression. All cylinders test within 5psi of each other.
Diagnosed issue with GM Tech 2 tool by turning individual injectors on/off.
When switching 4 or 6 on/off the engine running did not change.
Unplugged injectors to 4&6 to confirm the cylinders were "dead".
Right bank 02 seems VERY slow in open loop whereas Left 02 does not.

Replaced injectors 4&6 with no change.
Replaced ECM with no change.
I know it cant be the coil or opti.

Could it be the ignition module mounted to the coil ???

ANY help would be GREATLY appreciated !!!!

 

make sure the wires are on the opti correctly

 

Thanks Dave !
Turned out my mechanic installed wire #4 on the opti where #6 was supposed to be and vice-versa.
Guess I should have checke the easy things first, but did not suspect he would do this as I have used him for years....