96 ranger 3.0 no compression cyl 1

J

joncf

New Member
I recently bought this mazda (ranger) 4x4 3.0 ltr w/94k with a engine miss. turns out there is very little to no compression just in that cylinder. engine was compression tested and also performed a air leak test with no leaking at all . pull the valve cover off and all valves rods are moving like they should. We next took the plenum off to check for air restriction and it looked ok.
also the engine does not smoke and make any noises. We are at a stand still right now. We talked to someone and they said possibly valve timing off.

anyone have any suggestions?
 
well with no compression, either a valve is bent not closing all the way, ring is bad, threads for the spark plug are messed up and leaking there. not good
 
A bad valve or messed up plug should show in a leak down test. I don't know how you loose one cylinder from bad valve timing in a pushrod engine, that should be an all or nothing deal there. Rings or fuel wash would be my first suspect.

Did you do a wet compression test after the initial and see if it came up any?
 
with the valve cover off I can see everything moving like it should. Also we did the leak down test with all the plugs out a tdc valves closed and NO air loss with 35psi.
Right now I am soaking the cylinder with marvel and rotating it by hand. and hoping the ring will free up if that is problem. Just about ran out of ideas.
Also the truck sat for about a year when I bought it thats why I am leaning towards stuck ring.
 
my bad the leakdown with all plugs in except air fitting... compression test all plugs off...
anyway what exactly is the fuel wash
 
Fuel wash is when you get too much raw gas into the cylinder, from either a lack of spark, or a leaking injector. It gets into the metal and causes the rings to not seal properly.

A minor case will cost you between 5 and 20% and can usually be cleared up by fixing the issue, changing the plug and oil and running the piss out of it.

A major case requires new rings on the dead cylinder. The real problem is that once the cylinder drops below 90 PSI it can't fire and so it can't clear itself.
 
Ok ... The prior owner probably ran it like that for a while without fixing possibly fuel problem. I am just wondering why when we did the leak down test we could not tell the ring damage.
I guess soaking cylinder right know is only option then. thanks
 
Leave it sit for a day. Then do your compression test on that cylinder again, take your reading, and then add a tablespoon of oil to the cylinder through the plug hole. Repeat test. If the reading bumps a lot, you have a ring issue.

A leak down test looks for big holes. 35 PSI won't be enough to get past the rings in any state of crappiness.
 
Scrambler82 said:
Have you had the injectors tested ?
Click to expand...

Do tell, what would that accomplish right now?

He has no compression. A bad leak from an injector could cause fuel wash, which can kill compression, but usually leaves more than 0.

One thing I haven't considered until today, head gasket. But that would probably show in another cylinder or a leak down.

Injector test has nothing to tell us right now since we know there is a big compression issue.
 
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