How do dealerships check for this? I was recently told by one that it was my opti causing the miss fire and detonation, but was it really? And how can I catch them if they are just guessing? Thanks.

Dealership report: Found two dead cylinders 4 & 7. 4 Misfire caused by damaged spark plug. No spark from distributer for #7. Distributor Assy.

They never observed the detonation since it only occurs under a load.

I have pics of the plug I removed from #2 and the plug they removed from #4. Number #4 was just black and #2 had the white part melted and the metal part above it pitted and damaged. (not the arcing peice)

-Dustin-

 

well, Im a dearlership tech. perhaps I can answer you question. sounds like you have a current misfire (a cyl thats not firing at all). thats easy to check cause you just put a tester on the end of the wire, if no spark, then install a test sp. plug wire in the opti on that cyl. if still no spark, then the opti is bad.
if the eng. is misfiring only at high rpms, then you can do the same test, but most times it will only happen under load. in that case, you would swap plugs and install a test sp. plug wire to see if it clears up. above that, all you can do is guess that the opti is bad (after youve ruled out fuel issues or mechanical eng. problems like lifters, springs, piston rings, etc.). if the dealership is doin the repair, it will be there loss if he guess's wrong. but if you have them diagnose it, and you replace the opti, your SOL if it still misfires. also there are codes that point to the opti, but I cant remember ever getting one w/a code for that. hope that helps you understand better.
chris

 

Are there any programs that can be used by a home user with an ALDL cable to detect a missfire on certain cylinders and or a failure from the opti?

 

Only OBD-II can detect misfires on individual cylinders.

 

Lucky me

 

IrocSS85, Thanks thats basically what I was looking for. I asked the tech some questions, of course he checked the flow on the injectors and coil and such. Found one bad plug and #7 wasnt getting spark from the Opti. Thats all I know, but he personally assured me that the dealership costs to much and to replace it on my own if I can.

-Dustin-