What could cause these # coils to not work?
What could cause these # coils to not work? 3, 7, 4, and 6 coils are not working. The setup is running MSD ignition with a 500 CFM carb LS1. The setup used to run just fine before the last MSD box got bad. When we installed the new one and the problem is still there. After doing alot of testing we found out that the problem could not be from the MSD box. We even returned the stock LS1 PCM and connected everything and still those 3, 7, 4 and 6 coils are not firing. Keep in mind these coils are changed (New set in).
So where could the problem be? Could it be a sensor went bad? How would that cause the coils to not fire.
Any suggestions?
So where could the problem be? Could it be a sensor went bad? How would that cause the coils to not fire.
Any suggestions?
Originally Posted by joecar
Dead coils or bad wires/connectors to coils.
Does the problem move with the coils if you swap them with the working coils...?
Does the problem move with the coils if you swap them with the working coils...?
Would a crank sensor cause such a thing?
TECH Senior Member
Joined: Apr 2002
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From: So.Cal.
Originally Posted by LSs1Power
No.. That is the crazy thing. We changed a whole new set of coils and wires and the same banks have the problem.
Would a crank sensor cause such a thing?
Would a crank sensor cause such a thing?
a. while cranking check RPM readout using a scan tool (if PCM is connected); if no RPM, then crank sensor or it's wiring could be bad; crank sensor is used to trigger coils (and injectors if you had them).
b. if RPM is okay, then check wires that trigger the coils; remove PCM/MSD connector and using wire diagram ohm out the wires from PCM/MSD to coils; check ground connections.
Originally Posted by joecar
If the problem does not move when the coils are swapped, do this:
a. while cranking check RPM readout using a scan tool (if PCM is connected); if no RPM, then crank sensor or it's wiring could be bad; crank sensor is used to trigger coils (and injectors if you had them).
b. if RPM is okay, then check wires that trigger the coils; remove PCM/MSD connector and using wire diagram ohm out the wires from PCM/MSD to coils; check ground connections.
a. while cranking check RPM readout using a scan tool (if PCM is connected); if no RPM, then crank sensor or it's wiring could be bad; crank sensor is used to trigger coils (and injectors if you had them).
b. if RPM is okay, then check wires that trigger the coils; remove PCM/MSD connector and using wire diagram ohm out the wires from PCM/MSD to coils; check ground connections.
