Ignition coil problems.

[Toddmc66]

Having a problem with the coil pack dropping two cylinders on the same coil. The drivers side coil #3 & #6 keeps dropping out while driving. It will loose spark and then a mile or two it will come back on line. Under boost or high rpms the ignition starts breaking up. Checked all connections and all are good. Before I replace the coil pack or module I was hoping to get some input. New plugs and wires are good. All other coils are firing, just the one coil is failing. I'm assuming it's the coil pack because if it was the module none of the coils would fire,,, past experiences unless you've seen different.
Any help would be appreciated.

 

[GNVenom]

Erratic signal from CRANK sensor will cause this. Possibly a bad or misaligned sensor, or the connector on either the sensor or the CCCI module.

Also, an erratic CAM sensor signal will cause the coils to "reset" to the first coil, skipping over the center coil. When in doubt, replace the sensors.

Finally, a worn thrust bearing on the crankshaft will allow the entire crank to slide forward under acceleration, and move the interrupter ring sense zone away from the crank sensor. Look for excessive end play on the crankshaft.

 

[Toddmc66]

Erratic signal from CRANK sensor will cause this. Possibly a bad or misaligned sensor, or the connector on either the sensor or the CCCI module.

Also, an erratic CAM sensor signal will cause the coils to "reset" to the first coil, skipping over the center coil. When in doubt, replace the sensors.

Finally, a worn thrust bearing on the crankshaft will allow the entire crank to slide forward under acceleration, and move the interrupter ring sense zone away from the crank sensor. Look for excessive end play on the crankshaft.

 

[Toddmc66]

I actually just replaced the main bearings a noticed thats When I started having this problem. I looked at the crank sensor ant it was rubbing the ruluctor. This may be from the cranks position due to the new bearings. I repositioned the crank sensor and it still have the problem. Since the damage has already been done I'm replacing the crank sensor for good measure. Thanks for the input.

 

[Toddmc66]

Erratic signal from CRANK sensor will cause this. Possibly a bad or misaligned sensor, or the connector on either the sensor or the CCCI module.

Also, an erratic CAM sensor signal will cause the coils to "reset" to the first coil, skipping over the center coil. When in doubt, replace the sensors.

Finally, a worn thrust bearing on the crankshaft will allow the entire crank to slide forward under acceleration, and move the interrupter ring sense zone away from the crank sensor. Look for excessive end play on the crankshaft.

 

[Toddmc66]

Put new crank sensor on and still have the problem. After about 10 miles of driving the ignition dropped two cylinders again. Ohmed out the coil and one coil is open the other two are at 12.77 ohms. On my way to get another coil. Will let you know how it goes.

 

[626gn]

Good rule of thumb is to change the coil pack and module as a set. Its possible your module is bad too. If you put a good coil on a bad module it will take it out, again.

 

[Toddmc66]

Put new crank sensor on and still have the problem. After about 10 miles of driving the ignition dropped two cylinders again. Ohmed out the coil and one coil is open the other two are at 12.77 ohms. On my way to get another coil. Will let you know how it goes.

Good rule of thumb is to change the coil pack and module as a set. Its possible your module is bad too. If you put a good coil on a bad module it will take it out, again.

Thanks for the advice, will do.

 

[Dreamn4GN]

Anything come of this? Trying to determine if this is also my issue. Car reacts the same under any load it pretty much dies out. All was well until I made a little 0-60 pull from a dig.

 

[Toddmc66]

Anything come of this? Trying to determine if this is also my issue. Car reacts the same under any load it pretty much dies out. All was well until I made a little 0-60 pull from a dig.

Next step in this ignition problem. The MSD Did digital 4 box was the problem. I removed it and connected the factory connections with a new module and coil pack. The car ran great, smooth idle, great response, but still a little ignition break up under heavy throttle. I decided to park the car for the night and drive it to work the next day. (WRONG)!! Upon starting it in the morning it would crank but not start. After a few quick checks I had power and ground, crank and cam signal but no fire. Swapped out the module with a spare and now I have fire but the timing of the firing order is off. Now you have to understand I'm a 20 yr master technician and yes I've checked all the usuals. Ignition module connections and plug wires are in the correct positions. When cranking the engine won't run but acts like the plug wires are crossed or the timing chain has jumped. Neither of these is the case. I'm waiting on a new module and coil pack. I'll update after I install both.

 

[Toddmc66]

Anything come of this? Trying to determine if this is also my issue. Car reacts the same under any load it pretty much dies out. All was well until I made a little 0-60 pull from a dig.

Next step in this ignition problem. The MSD Dis digital 4 box was the problem. I removed it and connected the factory connections with a new module and coil pack. The car ran great, smooth idle, great response, but still a little ignition break up under heavy throttle. I decided to park the car for the night and drive it to work the next day. (WRONG)!! Upon starting it in the morning it would crank but not start. After a few quick checks I had power and ground, crank and cam signal but no fire. Swapped out the module with a spare and now I have fire but the timing of the firing order is off. Now you have to understand I'm a 20 yr master technician and yes I've checked all the usuals. Ignition module connections and plug wires are in the correct positions. When cranking the engine won't run but acts like the plug wires are crossed or the timing chain has jumped. Neither of these is the case. I'm waiting on a new module and coil pack. I'll update after I install both.

 

[Toddmc66]

Anything come of this? Trying to determine if this is also my issue. Car reacts the same under any load it pretty much dies out. All was well until I made a little 0-60 pull from a dig.

Next step in this ignition problem. The MSD Dis digital 4 box was the problem. I removed it and connected the factory connections with a new module and coil pack. The car ran great, smooth idle, great response, but still a little ignition break up under heavy throttle. I decided to park the car for the night and drive it to work the next day. (WRONG)!! Upon starting it in the morning it would crank but not start. After a few quick checks I had power and ground, crank and cam signal but no fire. Swapped out the module with a spare and now I have fire but the timing of the firing order is off. Now you have to understand I'm a 20 yr master technician and yes I've checked all the usuals. Ignition module connections and plug wires are in the correct positions. When cranking the engine won't run but acts like the plug wires are crossed or the timing chain has jumped. Neither of these is the case. I'm waiting on a new module and coil pack. I'll update after I install both.

 

[Dreamn4GN]

What about cam sensor? I know mine was used but in decent shape. Got a spare ignition coil from a buddy gonna swap it out and see what happens.

 

[Toddmc66]

Can sensor could be an issue. I would test it so you can eliminate it from what's good and what's not working. http://troubleshootmyvehicle.com/gm/3.8L/how-to-test-the-cam-sensor-1
Let me know how it goes with the coils.