Could be. Usually killing coils with overheating and white marks and cracks means not dumping the spark energy properly (wire, distr, cmp, plugs).


George

 

Misting the coil is OK


George

 

CMP Retard of 2.4 should be fine for now. You can put it right on zero later after things are fixed. But OK - problem is still there. I guess I never realized the severity of it (won't go over 50 mph). Maybe misfires damaged the cat a long time ago?

Some people pull O2 sensors ahead of converter and drive it to see if things improve. But noisy and chance of burning things with exhaust. Your choice.

There is a way of using a compression gauge with the engine running to definitively test efficiency of exhaust exiting the cylinder. If snap compression readings while running are all over 80% of the cranking compression values, then exhaust restriction is imminent. Because Blazers are such a pain to get at the plugs, I would just pick an easy cylinder for testing and test it per the instructions below. If one is OK it is very unlikely that exhaust (cat converter) is plugged. But if it isn't, I would be taking it back to that exhaust guy!

https://support.alldata.com/article/...pression-tests

 

I replaced the coil and the truck runs much better. It will go over 100kmh now. It still has a little shake when I'm stopped at lights. I still have to adjust the distributor to get the cmp closer to zero. But what a difference the coil swap made along with getting the cmp down 😉.

 

Did the bug zapper sound go away? If not the truck might kill this coil as well.


George

 

No the bug zapper is still there and now I have CEL P0351....this truck is starting to be a nuisance.

 

P0351 can be a lot of things but a good place to start is identify the location of the bug zapper and correct that problem. If that does not bring joy then it can be a tough problem to solve but not impossible. More advanced diagnostic skills are required but I can help guide you if you have a few pieces of test gear and the persistence/patience.

I will be glad to help if you want to get to the bottom of this part of your problem but you have direction from Les to check your back pressure first.


George

 

I had the bug zapper problem with the old wires cap and rotor. I still have the bug zapper problem with the new wires cap and rotor and plugs. Oh and new coil. So where do I go from here. As far as checking back pressure goes ...I don't have anything to do that and would have to go buy the tools. This truck has been a money pit for me !

 

I'll let Les give you new direction on your possible exhaust restriction issue.

For the bug zapper get in the dark with a water bottle and try to find it. If that does not work listen until you get close and then spray again. Are you sure that the bug zapper is electrical arcing and not valve train noise like lifter ticking?

George

 

Ya,I'm sure it leaking spark. It comes and goes. I heard it when I'm under a bridge sometime if it quite. I have really good hearing. I do have another ecu that I can plug it but I don't have anyway of doing the crank relearn procedure. I've been reading and they say it could be related to the ecm. At this point I would be willing to try anything. Should I be swapping the coil back to the old one ? I just don't know what to try next.