Installed new Champion 7034 plugs and there was an immediate loud metal on metal knock on start up followed by low level clanking, and within a few seconds it was misfiring. I inspected and reinstalled the plugs and it did the exact same thing on start-up; it did this twice in a row after installing the new plugs with identical failure characteristics. I verified the plug cable routing and confirmed the pistons are all still connected and moving freely when manual hand cranking. My insurance company’s OBD2 dongle is not reporting a fault code.
Last summer I had my first overheat and replaced the entire cooling system along with many other wear-out items preemptively. I was thinking my next step would be to camera endoscope the spark plug holes to see if a piston is cracked. I was sure I made a mistake with the spark plugs until I inspected and confirmed the plugs are undamaged. I did not look closely for debris around the sparkplug before removing them, but I didn’t notice any interference hand fitting the sparkplug socket either. Also, the cables are new as of last year, but there is a small split in the insulator jacket end shroud. An electrical gremlin from the cable damage/shorting could be causing chaos in the timing, and what I’m hearing could be the valves knocking as the engine controller then tries to compensate the timing and resulting misfire. I had the distributor tower one tooth off many years ago, and it seems like this could (hopefully) be a timing issue based on how the engine will start and run for 20-30 seconds and then start misfiring.
I'm the original owner of the 2000 2.5l TJ with 183K, and I've done all the maintenance myself. I had everything fixed except for the rear transmission seal, which I was saving for the first clutch replacement. I was thinking I had ten more years of life in the Jeep until this, yikes.
Last summer I had my first overheat and replaced the entire cooling system along with many other wear-out items preemptively. I was thinking my next step would be to camera endoscope the spark plug holes to see if a piston is cracked. I was sure I made a mistake with the spark plugs until I inspected and confirmed the plugs are undamaged. I did not look closely for debris around the sparkplug before removing them, but I didn’t notice any interference hand fitting the sparkplug socket either. Also, the cables are new as of last year, but there is a small split in the insulator jacket end shroud. An electrical gremlin from the cable damage/shorting could be causing chaos in the timing, and what I’m hearing could be the valves knocking as the engine controller then tries to compensate the timing and resulting misfire. I had the distributor tower one tooth off many years ago, and it seems like this could (hopefully) be a timing issue based on how the engine will start and run for 20-30 seconds and then start misfiring.
I'm the original owner of the 2000 2.5l TJ with 183K, and I've done all the maintenance myself. I had everything fixed except for the rear transmission seal, which I was saving for the first clutch replacement. I was thinking I had ten more years of life in the Jeep until this, yikes.