86 Cherokee appears to have one dead cylinder
 

Replaced in chronological order:
Plugs
Ujoints
Clutch Master Cylinder
Cap
Rotor
Wires
Muffler
Catalytic Converter
Tailpipe

Prior to doing all of these things, this 4 cylinder 2.5 liter Jeep all of a
sudden started running really rough. It obviously needed ujoints, muffler
etc., and clutch master in order to drive it at all, and the rest of the
stuff I did in an attempt to cure the rough running.

Today after the muffler job, I stopped by a shop and asked for an opinion.

One of the mechs took the time to pull the plug wires off each plug one by
one...

Here's what happened:

Forward cylinder:
Engine slowed down when wire pulled off plug.

Second cylinder from front:
Engine slowed down when wire pulled off plug.

Third cylinder from front:
Engine did not slow down at all when wire pulled off plug.

Rear cylinder near firewall:
Engine slowed down when wire pulled off plug.

So it looks as though the third cylinder from front is basically doing
nothing.

Any ideas on what's up?
Mech mentioned valves, piston, and rings.

--
Skip

Re: 86 Cherokee appears to have one dead cylinder
 

Do a compression check:
http://www.georgiazclub.com/tips/ztech/comptest.htm
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Skip wrote:
>
> Replaced in chronological order:
> Plugs
> Ujoints
> Clutch Master Cylinder
> Cap
> Rotor
> Wires
> Muffler
> Catalytic Converter
> Tailpipe
>
> Prior to doing all of these things, this 4 cylinder 2.5 liter Jeep all of a
> sudden started running really rough. It obviously needed ujoints, muffler
> etc., and clutch master in order to drive it at all, and the rest of the
> stuff I did in an attempt to cure the rough running.
>
> Today after the muffler job, I stopped by a shop and asked for an opinion.
>
> One of the mechs took the time to pull the plug wires off each plug one by
> one...
>
> Here's what happened:
>
> Forward cylinder:
> Engine slowed down when wire pulled off plug.
>
> Second cylinder from front:
> Engine slowed down when wire pulled off plug.
>
> Third cylinder from front:
> Engine did not slow down at all when wire pulled off plug.
>
> Rear cylinder near firewall:
> Engine slowed down when wire pulled off plug.
>
> So it looks as though the third cylinder from front is basically doing
> nothing.
>
> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.
>
> --
> Skip

Re: 86 Cherokee appears to have one dead cylinder
 

Do a compression check:
http://www.georgiazclub.com/tips/ztech/comptest.htm
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Skip wrote:
>
> Replaced in chronological order:
> Plugs
> Ujoints
> Clutch Master Cylinder
> Cap
> Rotor
> Wires
> Muffler
> Catalytic Converter
> Tailpipe
>
> Prior to doing all of these things, this 4 cylinder 2.5 liter Jeep all of a
> sudden started running really rough. It obviously needed ujoints, muffler
> etc., and clutch master in order to drive it at all, and the rest of the
> stuff I did in an attempt to cure the rough running.
>
> Today after the muffler job, I stopped by a shop and asked for an opinion.
>
> One of the mechs took the time to pull the plug wires off each plug one by
> one...
>
> Here's what happened:
>
> Forward cylinder:
> Engine slowed down when wire pulled off plug.
>
> Second cylinder from front:
> Engine slowed down when wire pulled off plug.
>
> Third cylinder from front:
> Engine did not slow down at all when wire pulled off plug.
>
> Rear cylinder near firewall:
> Engine slowed down when wire pulled off plug.
>
> So it looks as though the third cylinder from front is basically doing
> nothing.
>
> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.
>
> --
> Skip

Re: 86 Cherokee appears to have one dead cylinder
 

Do a compression check:
http://www.georgiazclub.com/tips/ztech/comptest.htm
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Skip wrote:
>
> Replaced in chronological order:
> Plugs
> Ujoints
> Clutch Master Cylinder
> Cap
> Rotor
> Wires
> Muffler
> Catalytic Converter
> Tailpipe
>
> Prior to doing all of these things, this 4 cylinder 2.5 liter Jeep all of a
> sudden started running really rough. It obviously needed ujoints, muffler
> etc., and clutch master in order to drive it at all, and the rest of the
> stuff I did in an attempt to cure the rough running.
>
> Today after the muffler job, I stopped by a shop and asked for an opinion.
>
> One of the mechs took the time to pull the plug wires off each plug one by
> one...
>
> Here's what happened:
>
> Forward cylinder:
> Engine slowed down when wire pulled off plug.
>
> Second cylinder from front:
> Engine slowed down when wire pulled off plug.
>
> Third cylinder from front:
> Engine did not slow down at all when wire pulled off plug.
>
> Rear cylinder near firewall:
> Engine slowed down when wire pulled off plug.
>
> So it looks as though the third cylinder from front is basically doing
> nothing.
>
> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.
>
> --
> Skip

Re: 86 Cherokee appears to have one dead cylinder
 

Skip did pass the time by typing:

> So it looks as though the third cylinder from front is basically doing
> nothing.

Correct

> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.

Newer and I'd say stuck injector or bad harness, but an
86 is gonna be good ol Mr. Carburetor.

If your piston was holed you would be getting exhaust out the
dipstick tube.

Collapsed lifter on the intake side of #3 would do that. If
the valve isn't opening fuel isn't goin in.

First up is a compression check across all cylinders. If the
compression is low, squirt in some oil and run the test again.
If compression picks up it's rings, if not it's valves. I doubt
it's the rings, that usually results in a rough condition with
lots of blowby and real dirty oil.

Your probably going to have to pull the valve cover and watch
as the engine turns. With luck it's just a collapsed lifter.
Or maby a broken return spring on the exhaust valve..

--
DougW

Re: 86 Cherokee appears to have one dead cylinder
 

Skip did pass the time by typing:

> So it looks as though the third cylinder from front is basically doing
> nothing.

Correct

> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.

Newer and I'd say stuck injector or bad harness, but an
86 is gonna be good ol Mr. Carburetor.

If your piston was holed you would be getting exhaust out the
dipstick tube.

Collapsed lifter on the intake side of #3 would do that. If
the valve isn't opening fuel isn't goin in.

First up is a compression check across all cylinders. If the
compression is low, squirt in some oil and run the test again.
If compression picks up it's rings, if not it's valves. I doubt
it's the rings, that usually results in a rough condition with
lots of blowby and real dirty oil.

Your probably going to have to pull the valve cover and watch
as the engine turns. With luck it's just a collapsed lifter.
Or maby a broken return spring on the exhaust valve..

--
DougW

Re: 86 Cherokee appears to have one dead cylinder
 

Skip did pass the time by typing:

> So it looks as though the third cylinder from front is basically doing
> nothing.

Correct

> Any ideas on what's up?
> Mech mentioned valves, piston, and rings.

Newer and I'd say stuck injector or bad harness, but an
86 is gonna be good ol Mr. Carburetor.

If your piston was holed you would be getting exhaust out the
dipstick tube.

Collapsed lifter on the intake side of #3 would do that. If
the valve isn't opening fuel isn't goin in.

First up is a compression check across all cylinders. If the
compression is low, squirt in some oil and run the test again.
If compression picks up it's rings, if not it's valves. I doubt
it's the rings, that usually results in a rough condition with
lots of blowby and real dirty oil.

Your probably going to have to pull the valve cover and watch
as the engine turns. With luck it's just a collapsed lifter.
Or maby a broken return spring on the exhaust valve..

--
DougW

Re: 86 Cherokee appears to have one dead cylinder
 

Collapsed lifter won't cause it to miss. It will cause the valve train to
clatter away but will still open the valve enough for the cyl to contribute.
Hydraulic lifter just takes up the slack, doesn't contribute to the opening.
Collapsed lifter first complaint would have been the noise. Broken valve
spring will cause a miss, but it's pretty uncommon. Comp test first order of
business.
Steve
"DougW" <post.replies@invalid.address> wrote in message
news:fE0Pb.8609$zy3.4571@okepread01...
> Skip did pass the time by typing:
>
> > So it looks as though the third cylinder from front is basically doing
> > nothing.
>
> Correct
>
> > Any ideas on what's up?
> > Mech mentioned valves, piston, and rings.
>
> Newer and I'd say stuck injector or bad harness, but an
> 86 is gonna be good ol Mr. Carburetor.
>
> If your piston was holed you would be getting exhaust out the
> dipstick tube.
>
> Collapsed lifter on the intake side of #3 would do that. If
> the valve isn't opening fuel isn't goin in.
>
> First up is a compression check across all cylinders. If the
> compression is low, squirt in some oil and run the test again.
> If compression picks up it's rings, if not it's valves. I doubt
> it's the rings, that usually results in a rough condition with
> lots of blowby and real dirty oil.
>
> Your probably going to have to pull the valve cover and watch
> as the engine turns. With luck it's just a collapsed lifter.
> Or maby a broken return spring on the exhaust valve..
>
> --
> DougW
>
>

Re: 86 Cherokee appears to have one dead cylinder
 

Collapsed lifter won't cause it to miss. It will cause the valve train to
clatter away but will still open the valve enough for the cyl to contribute.
Hydraulic lifter just takes up the slack, doesn't contribute to the opening.
Collapsed lifter first complaint would have been the noise. Broken valve
spring will cause a miss, but it's pretty uncommon. Comp test first order of
business.
Steve
"DougW" <post.replies@invalid.address> wrote in message
news:fE0Pb.8609$zy3.4571@okepread01...
> Skip did pass the time by typing:
>
> > So it looks as though the third cylinder from front is basically doing
> > nothing.
>
> Correct
>
> > Any ideas on what's up?
> > Mech mentioned valves, piston, and rings.
>
> Newer and I'd say stuck injector or bad harness, but an
> 86 is gonna be good ol Mr. Carburetor.
>
> If your piston was holed you would be getting exhaust out the
> dipstick tube.
>
> Collapsed lifter on the intake side of #3 would do that. If
> the valve isn't opening fuel isn't goin in.
>
> First up is a compression check across all cylinders. If the
> compression is low, squirt in some oil and run the test again.
> If compression picks up it's rings, if not it's valves. I doubt
> it's the rings, that usually results in a rough condition with
> lots of blowby and real dirty oil.
>
> Your probably going to have to pull the valve cover and watch
> as the engine turns. With luck it's just a collapsed lifter.
> Or maby a broken return spring on the exhaust valve..
>
> --
> DougW
>
>

Re: 86 Cherokee appears to have one dead cylinder
 

Collapsed lifter won't cause it to miss. It will cause the valve train to
clatter away but will still open the valve enough for the cyl to contribute.
Hydraulic lifter just takes up the slack, doesn't contribute to the opening.
Collapsed lifter first complaint would have been the noise. Broken valve
spring will cause a miss, but it's pretty uncommon. Comp test first order of
business.
Steve
"DougW" <post.replies@invalid.address> wrote in message
news:fE0Pb.8609$zy3.4571@okepread01...
> Skip did pass the time by typing:
>
> > So it looks as though the third cylinder from front is basically doing
> > nothing.
>
> Correct
>
> > Any ideas on what's up?
> > Mech mentioned valves, piston, and rings.
>
> Newer and I'd say stuck injector or bad harness, but an
> 86 is gonna be good ol Mr. Carburetor.
>
> If your piston was holed you would be getting exhaust out the
> dipstick tube.
>
> Collapsed lifter on the intake side of #3 would do that. If
> the valve isn't opening fuel isn't goin in.
>
> First up is a compression check across all cylinders. If the
> compression is low, squirt in some oil and run the test again.
> If compression picks up it's rings, if not it's valves. I doubt
> it's the rings, that usually results in a rough condition with
> lots of blowby and real dirty oil.
>
> Your probably going to have to pull the valve cover and watch
> as the engine turns. With luck it's just a collapsed lifter.
> Or maby a broken return spring on the exhaust valve..
>
> --
> DougW
>
>