1998 Chevy Camaro
3.8
dash lights = check engine
codes P1351
Repairs done prior = head gasket replacement
Work done to repair = replaced the coils and the electrical box they sit
on plus plugs and wires
tip/donation yes
tech = jk
question = I just replaced the head gasket on my car. When I was
finished the car would not start. After playing with it for a bit I figured
out it had no spark. So I replaced the little box the coils sit on (it
was expensive so I took it off a 98 Pontiac Grand prix gt 3.8) and it
started but the check engine light keeps coming on with a code P1351
saying ignition voltage high and open current. So I got another electrical
box and coils off a 97 Camaro 3.8 with the same part# the pontiac was a
different  part# box. It runs a lot better with no misses but the same
code keeps coming up. I have replaced the plugs and wires when I did
the head gasket. Now there are 2 things I have noticed 1. The cat is bad
in it and will be replaced in the morning. 2. I found a ground wire to
the electrical box broke so I soldered it back together. Well hope you
can help







JK:
Hello and welcome.
Thanks you very much for the tip/donation. The Ignition Control Module (ICM)
sends signals that the PCM requires for fuel control and  spark advance
calculations. At the start of engine crank, the ICM controls spark advance  
(Bypass mode.) When the second 3X reference pulse is recognized by the PCM,
the PCM  applies 5 volts to the Bypass circuit, commanding the ICM to switch
spark advance to PCM  control (IC mode). If the PCM detects an open in the IC
circuit, DTC P1351 will set. The  engine will start and may run in Bypass mode
timing.
It is possible that damage has cured to the IC control circuit wire, or the low
reference  circuit wire between the PCM and the ignition control module. Just be
sure the ignition  modules are the same part #
You are going to need a digital multimeter to do some tests.
First disconnect the pcm(connector C1-blue) and ignition control module. Check
for continuity of circuit 423 (white) between pcm and ignition control module with
key off. Then  do the same for circuit 453(red/blk). Less than .5 ohms is ok. If high
resistance, or open  circuit on either, you will need to trace the wire from pcm to
module very carefully. Also  look very carefully at terminals inside ignition module
connector for damage. Damage may  occurred during the several times the
connector has been on and off. Also pull lightly on each individual wire at ignition
module connector to make sure the wires do not stretch.
Once again, thank you for the tip/donation.
See schematics i will send in a few moments...