Re: One cylider low compression
Something isn't right with the numbers. The difference in compression should only be 20 psi at best between a wet and dry compression test.
If the engine that you have is anything like the 1.8 Mazda engine, your going to find that one of the exhaust valves in #3 is damaged. (missing a small piece from the valve face. "burnt") Not a big deal. Just need to replace the valve, and of course, the head gasket. You may want to think about whether or not replacing just one valve is a good idea. After all, the valves all have the same use on them. Its only a matter of time before more valves fail. It might be years, or it might be a few miles before the next one lets go.
The best I know, no one has figured out why the #3 drops a valve. I'm not even sure many have put this together yet, but I have personally had 4, 1.8 Mazda engines lose one of the #3 exhaust valves, and have heard of several others.
It'd be interesting to see if this valve failure is being carried over into the Ranger engines. Anyone else have stories of exhaust valve failure?
Did a scan tool really state that one cylinder had more carbon than the others? I find this interesting, I mean... how could this be measured?
Rangers, '95, 2.3, '98 2.5, 4x2 extra cab's, '96, 2.3 base model, '99, Mazda B3000.