Wanker Delux
The Other Greg
- Location
- Too Far North
My #3 cylinder seems to be dead for some reason. Plenty of spark, and compression seems fine. I also adjusted the valves a while ago. Any ideas?
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Zuk missing a cylinder
- Thread starter Wanker Delux
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Get Me wired
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The only thing left is a combustible air/fuel mixture.
So what was the compression anyway? How did you check the spark?
So what was the compression anyway? How did you check the spark?
jp008
Well-Known Member
- Location
- Heber City
Check the vacuum tube that runs from your air cleaner(the piece ontop of the carb) to the #3 intake port. Mine came off once and I almost beat my head to a bloody pulp trying to figure it out. Once I found it everything was fine.
(my.02)
(my.02)
Wanker Delux
The Other Greg
- Location
- Too Far North
Thanks, I'll check that out in the morning.
I know it has spark, caus when trying to check, I got a nice big jolt
. I think it might be a good idea to keep the spark plug booties clean .
jp008
Well-Known Member
- Location
- Heber City
Mmmmmmmmmmm a nice jolt of "Why the He11 did I just do that?"
Wakes you up doesn't it?
Wakes you up doesn't it?
Get Me wired
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I'm pretty sure a bad plug wire gives the same, if not worse, jolt a good plug wire does. And I don't know about the rest of you but after about 10K volts it all feels the same to me.
Wanker Delux
The Other Greg
- Location
- Too Far North
well... I replaced that tube, it does seem to make a diffrence in how the engine runs, but I still notice no diffrence wether the wire is pluged in or not. Is this normal?
I have a service manual somewhere on CD, I just need to find it and do a bit of reaserch.
I have a service manual somewhere on CD, I just need to find it and do a bit of reaserch.
Wanker Delux
The Other Greg
- Location
- Too Far North
well.. I have done a little reaserch, and found that the tube I replaced is the hot idle compensator valve. Basicly, if the temp gets to high, it lets in a little more air to lean the mixture a little. This will affect how the engine idles, but it shouldn't cause a cylinder to quit.
The other possilility is the PCV(positive crankcase ventlation) valve. This sits just over the #3 intake. Would this cause a problem it got filled with oil? I guess I'll pull it and take a look.
The other possilility is the PCV(positive crankcase ventlation) valve. This sits just over the #3 intake. Would this cause a problem it got filled with oil? I guess I'll pull it and take a look.
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I would think that the PCV fitting or hose would have to be leaking to cause a problem. If it was pluged you would just have the excess crankcase pressure escaping through the vent or any other place it can (oil fill cap, valve cover gasket). So what was the compression?
Wanker Delux
The Other Greg
- Location
- Too Far North
the compression was around 140-145 on all the cylinders.
I think that the PCV valve is stick open. When I blocked it with my thumb, the engine idle suddenly became VERY smooth, then back to rough when I let it go.
So, I pulled the valve, and, as the service manual said, I blew though it.
It didn't offer much in the way of resistance, so I'm thinking it is stick open, lettin way to much air into the intake and leaning the #3 cylinder to the point where it is not combusting.
Might I recogmend that everyone check their PCV valve... This should give me back a few HPs...
I think that the PCV valve is stick open. When I blocked it with my thumb, the engine idle suddenly became VERY smooth, then back to rough when I let it go.
So, I pulled the valve, and, as the service manual said, I blew though it.
It didn't offer much in the way of resistance, so I'm thinking it is stick open, lettin way to much air into the intake and leaning the #3 cylinder to the point where it is not combusting.
Might I recogmend that everyone check their PCV valve... This should give me back a few HPs...
Wanker Delux
The Other Greg
- Location
- Too Far North
BINGO!
The new PCV valve did the trick! She's purin like a kitten now.
My theory:
The PCV is mounted right above the #3 intake. With a stuck open valve, excess air is forced into the manafold, displaceing the fuel/air mix that is suposed to be passing though, thus super leaning the mix that gets to the cylinder. This only affects anything at lower RPM when the airflow is slower, but at higher RPMs the suction from the cylinder is great enough to overcome the excess air from the valve.
Also, if you are having troubles passing emissions, you might try bypassing this valve altogether. That way, prettymuch only air goes though that cylinder, making for less emissions at the lower RPMs.
Thanks for the suggestions though, JP008 did get me pointed in the right direction.
P.S. Its a 3 dollar part, just go to autozone, its part # PCV141 in a white package
The new PCV valve did the trick! She's purin like a kitten now.
My theory:
The PCV is mounted right above the #3 intake. With a stuck open valve, excess air is forced into the manafold, displaceing the fuel/air mix that is suposed to be passing though, thus super leaning the mix that gets to the cylinder. This only affects anything at lower RPM when the airflow is slower, but at higher RPMs the suction from the cylinder is great enough to overcome the excess air from the valve.
Also, if you are having troubles passing emissions, you might try bypassing this valve altogether. That way, prettymuch only air goes though that cylinder, making for less emissions at the lower RPMs.
Thanks for the suggestions though, JP008 did get me pointed in the right direction.
P.S. Its a 3 dollar part, just go to autozone, its part # PCV141 in a white package
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