Hello everyone like alot of us i have a high mileage Chevy Blazer like most of us. Its a 1999 4X4 LS automstic with about 260,000 miles on it.s I am the umpteenth owner of this blazer. Since I've had it i have replace most of the electrical system and some fuel related parts. Including but not limited to TPS, spark plugs, spark plug wires, distributor cap, rotor button, starter, new battery, fuel pump, fuel filter, ignition control module is fine and recently I've had to replace the ignition coil twice I'm not quite sure what is killing the coil but if you have any ideas suggestions or experience with such an issue I'd love to hear from you

 

I have had many ignition coils that have failed on me also. I now carry one around with me, lol. I have found that the genuine AC Delco coils last the longest. All my previous coils had failed in the secondary windings causing weak spark.

 

The ignition coil is not grounded. It is mounted to the engine, but the circuitry inside does not contact the case. The only ground it sees, is when the ignition module supplies it to fire the coil. Poor ground / high resistance in the ignition module ground circuit can cause modules and coils to fail prematurely.

 

What do you suggest to remedy this. I put abfair amount of dielectric grease on the module maybe the wire leading to the module?

 

The back side of the ignition module needs heat sink compound so the heat from the module transfers to the aluminum heat sink that the module mounts to. Radio Shack has it available in a small tube. Silicone dielectric grease is for electrical connections.

Disconnect the ignition module connector. The black with white trace wire must show as close to zero ohms resistance to ground as possible. The other end of the wire is attached to the rear of the right cylinder head. PITA to get at. If resistance shows too high, solder on a piece of wire and attach it to a good, clean spot on the engine block, ie intake manifold bolt. This wire is where the ignition module gets its ground. It sends the ground through the white with black trace wire to the ignition coil. That wire, and its connections at the module & coil, must be good. Resistance end to end should be as close to zero as possible. If either of the wires are above 5 ohms, there's a problem. Less than 1 ohm is best.

 

Captian hook I'm going though icm's and coils every 2 years on my 2005 blazer 4x4. I did test the ground as mentioned above and I got 01.00 on my first test and 00.00 on tests after that. Do you think that would be ok ? Should I just ground it with another wire to be safe ? If so gound to the block or right to the negative of the battery ? Thanks in advance 😊. I value your opinion !