I am having a couple of issues on my 4runner. I can’t find a thread that talks about it and it won’t let me start one so I’ll tey here. First, my truck had this misfire so I towed it to our shop and I found a smashed spark plug in cylinder 1. Cylinder 1 also had no compression while all the others had 150psi. Before the misfire it made a ticking sound. (I have a 3vze 3.0 V6). Second problem is I converted my truck to manual. Originally auto. I swapped in an R150F transmission and got every thing working on except my automatic locking hubs and my speedo. My hubs just need to be a temporary fix because I’m planning on doing a solid axle swap next summer. However the speedo needs to be permanent. I believe the automatic had some kind of mechanical one and the manual has an electrical connection. The donor truck was a 91 4tunner and my truck is a 95

So I talked to my buddy (Toyota master mechanic) and he said it’s likely not a rod. He wasn’t sure what else it could be but he was almost positive it wasn’t a rod going out. What else could it be? I’m very handy and can rebuild an engine. I’ll be taking off the heads next week after I’m done with school. Is it possible that the valve just got stuck down? I just want an idea what to expect. I’m a college student with not a lot of money and this thing is my daily drive and I’ve put to much into it to sell

no sudden oil leaks. So I have zero compression on cylinder one but the other two on the same side have good compression at 150psi. I got a borescope today from harbor freight and it doesn’t look like there’s a single impact point from the plug on the piston head. There’s a bunch of little spots all over the piston head. Cylinder 5 on the same side also has the same marks. Piston 3 looked normal. I’ll post pictures of the pistons on separate posts in just a second.

This is the smashed plug. It’s only got one tiny hit. If it were the piston hitting it then the smash mark would be on the very top of it and not off to the side. Because the piston is coming straight at it and not at an angle like that
There’s no point of impact on the piston head where the spark plug would have impacted had the piston struck it. That large pea sized dimple is supposed to be there. These pictures are upside down due to the borescope orientation. Spark plug impact would have been in the middle of the piston head towards the bottom end.

haha with regards to the bore scope it was the cheapest one at harbor freight. And yeah I’m just going to give up on this engine. A buddy offered me his good long block for $100 so I’m just going to do a light rebuild on that one.

I’m suspecting:
1-a burnt valve,
2-missing part of piston/valve, stuck between valve and head, same chip got between plug and piston first then stuck between valve and head ?
Can you see the valves with your scope?

no unfortunately not.theres no way to see the valves without removing the heads. After I get the old engine out I’m going to dismantle it to see if it’s worth fixing as a back up or to sell. I’ll let you know what I ind so if someone else runs into the same problem they will know what to expect