Yes, plug gap *IS* that important (1 Viewer)

Oct 23, 2019
Southern Minnesota
Last year, some dumb kids sold off a beat-to-shiz 89 FJ62 for $1k in WV. My buddy picked it up for me and had it shipped up to MN, where is has mainly been sitting with little movement in the back corner of my shop.

Now that I picked up a rear window seal and put the liftgate glass in from my parts rig, its time to start sorting everything. Every wire in the rear body harness has been replaced, they are now all red and all the same gauge, so I'm going to splice in the wiring harness from the parts rig. Hopefully this will fix the left turn signal/brake issues (cross-feeding).

Anyway, the thing ran like a turd. Straight couldn't get out of its own way, popping and misfiring the entire time. Last week, I verified the firing order and cleaned the contacts inside the dizzy cap. It didn't help much. Today, I finally got around to the nitty-gritty on it while waiting for paint to dry on my dually's diff cover.

I pulled the plugs one by one, cleaned them, set the gap, and ran a compression test. Cylinder 1 had an AC Delco plug, gapped at 0.032, compression of 128. Number two had an unknown brand in there set to 0.033, compression 120. Number 3 had an AC Delco at 0.032, compression 118. Same for cylinder four. Cylinder 5 had an NGK set to 0.023, compression 120, and cylinder 6 had an AC Delco, bent down to 0.008 or so,with compression at 120.

Seriously? 3 different brand plugs?

I set them all to 0.043, like the FSM says, and I'll be ordering ND plugs before putting it on the road.

I fired the beast up, and the straight pipes (yes, dumb kids) roared to life. I put it in gear and accidentally dug a 6 inch deep hole in the gravel with a quick power brake. I throttled down the driveway, and MAN this thing can actually move!

Its still popping and backfiring at idle, so I have to check the timing and put some sort of muffler on it, but I am a happy camper today. With the amount of mud in the intake piping, I was sure they had screwed up something expensive internally. Nope. They were just really dumb.
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