Dead cylinder = Confused

[the_dingman]

Ok, so I posted last week about how my truck started running poorly on the way to work. I finally got a day off to play, and I started with the idea of removing each spark plug wire while the engine was running to see if it was indeed a dead cylinder.

Pulled the first cylinder's wire, no change. So my first cylinder is dead. I proceeded to change all four plugs, all four wires and the distributor cap (I had pulled a basically brand new cap and wires from my parts truck).

I started up the truck, and it seemed to be fine, however I pulled the wire again, no change. When I tried to pull the wire out of the distributer cap, it would randomly shoot little sparks out, so it seems that it should be sparking.

None of my plugs were damaged, however where the 3 good cylinder's plugs were basically all black, this one was a lighter color, and looked more new than anything.

What else could be the problem?

 

[04 sc V8]

Was #1 cyl plug wet at all? I would do a compression test on that cyl. Maybee a burned valve or if compression is OK a bad fuel injector.

 

[the_dingman]

There was a good hour between when I tested it and when I changed the plug, so it didn't seem wet.

It sounds like it's compressing, it's almost as though I can hear it compressing and releasing (though I may be full of it).

how hard is it to change an injector?

 

[04 sc V8]

Just because it sounds like it has compression doesn't mean that it does. Autozone should loan a compression tester for free. The fuel injecturs aren't to bad to get at. The intake plenum needs to come off to do so.

 

[the_dingman]

Ok, so I haven't had a chance to check the compression yet, but I'm not sure I need to now... Here's what I've found:

The truck runs fine, just a little rough until it's warmed up a little.

Once it's warmed up just a bit, it runs smoother, but still choppy. At this point little black specks of liquid start shooting out the exhaust, and if the oil filler cap is removed, little specks of oil shoot up out the cap. The radiator will slowly overflow if the cap is removed, but there is no bubbling, only the level slowly rises (I think that's normal).

It's looking to me like I might have a bad piston ring. I imagine that'd require a complete rebuild to fix, so I may be better off just replacing the engine. Is there anywhere I can find a rebuilt 22RE for purchase?

 

[04 sc V8]

The black specks out the tailpipe is probably condensation mixed with carbon from short runs, the oil spraying out the fill hole with the engine running is normal for OHC engines and coolant expands when heated so that is normal too. To diagnose an internal problem you really need to perform a compression test. Get a tester and I'll explain how to do it. It's really easy if you're able to remove all 4 spark plugs. I'm assuming your capable of doing that?

 

[the_dingman]

I just replaced all 4 plugs, wires and the distributor cap in hopes it was an ignition problem, so I can definitively do that. I'm capable, but ignorant, good with my hands, but not an experienced car guy.

You have, however, just made my day, in letting me know that I might not be completely f***ed.

As soon as I get a chance to get the compression tester, I'll give it a go. I know that the tester goes in the spark plug hole, but I'm not sure what to do from there. :

 

[04 sc V8]

OKay here's the rundown. Remove all 4 spark plugs and the fuel pump fuse. Take the ignition coil wire off the distributer cap and let it rest against the body, grounding out away from where you're working. Remove the air filter element from the housing and install the gauge in #1 cyl. hand tight. Get in the truck and while holding the accelerator pedal to the floor, crank the engine over for 5-10 seconds. Counting so you can repeat with all 4 cylinders. Record the reading on the gauge and repeat with all 4 cylinders. Release pressure from valve on gauge before removing it from the cyl. head. They should be within a few psi of each other. If one is low you can add a tablespoon of clean engine oil and repeat the test. If pressure is higher with oil, worn rings. If not, bad valve or something similar. Hope this helps!

 

[drmorbius]

None of my plugs were damaged, however where the 3 good cylinder's plugs were basically all black, this one was a lighter color, and looked more new than anything.

What else could be the problem?

The light color on the plug tells me that cylinder is running lean. I would replace the fuel injector associated with that cylinder. You might try a fuel injector cleaner, it just might work.

 

[04 sc V8]

Yeah, like I said before, it could be the fuel injector, but they're not that easy to change on a 22re. So for a piece of mind, I would perform a compression test. Fuel injector cleaner might help, but it usually won't if the injector is so bad that the cyl isn't firing.

 

[drmorbius]

:iagree:

 

[the_dingman]

Well, I finally took the advice given and got around to a compression test. After warming up the engine, I tested all four cylinders, coming up with exactly 180 for #2, 3 & 4, and about 183 for #1 (the dead one). It looks like my compression is good (very), and I need to move on to changing the fuel injector.

I started to work on removing the air intake to get at the injectors, and I couldn't get it off. Is it possible to loosen it enough to get at the injector without completely removing it and all the hoses attached?

I removed the six bolts connecting it to the manifold, the one on the support bar on the bottom front, and the two connecting to a metal pipe on the back, and it isn't coming loose... any ideas?