Cylinder 6 Misfire... Damsel in Distress
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
I'd do a few simple tests before laying out any cash for parts - do you have a set of jumper cables?
My favorite method of checking for spark is to pull off the spark plug wire of the offending cylinder, and put another good spark plug in the end of the wire. Use the jumper cable to connect the plug to a good ground (grip the plug with one clip, attach the other to a handy place on the engine block).
If you're not sure of the spark quality, just do the same test on a known good cylinder and you'll have something to compare it with.
This will tell you if the problem is in the ignition system or not, and can save lots of hours and dollars in frustration and unneeded parts.
As for the plugs themselves, I'd pull the #6 plug and another plug from a good cylinder to compare them. Is the gap noticeably wider on the #6 plug? How about other differences? BTW, there's a sticker under the hood that says what the spark plug gap should be. The plugs should be reasonably close to this.
If the spark looks ok, I'd do a compression test. If you ask around, someone in your friends and family may have a tester you can borrow. And some parts stores will loan tools, for a deposit.
My favorite method of checking for spark is to pull off the spark plug wire of the offending cylinder, and put another good spark plug in the end of the wire. Use the jumper cable to connect the plug to a good ground (grip the plug with one clip, attach the other to a handy place on the engine block).
If you're not sure of the spark quality, just do the same test on a known good cylinder and you'll have something to compare it with.
This will tell you if the problem is in the ignition system or not, and can save lots of hours and dollars in frustration and unneeded parts.
As for the plugs themselves, I'd pull the #6 plug and another plug from a good cylinder to compare them. Is the gap noticeably wider on the #6 plug? How about other differences? BTW, there's a sticker under the hood that says what the spark plug gap should be. The plugs should be reasonably close to this.
If the spark looks ok, I'd do a compression test. If you ask around, someone in your friends and family may have a tester you can borrow. And some parts stores will loan tools, for a deposit.
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
I figured if I have to go through the coil packs to get to the plugs anyways, I might as well replace the #6 pack (provided I make it that far. Lol).
If I had the monies for a $200 coil pack, I'd probably get a $120 part and pay the difference in labor at a shop.... But as it were, the bulk of my paycheck goes towards paying someone's debt. So I'm trying to do this as cost effective as possible. Hence why I came here to beg my case to you amazing and wonderfully insightful community members. =>
The general consensus seems to be basically to start with the spark plugs, so that is where I will start on Saturday. Don't be surprised if you see posts of fear between now and then, and utter loss and confusion the day of. Lol.
I hope to take pictures along the way, so as to chronicle my feeble attempts of becoming mechanically self-sufficient. If niching else, it will give you all something to laugh about for the weekend.
If I had the monies for a $200 coil pack, I'd probably get a $120 part and pay the difference in labor at a shop.... But as it were, the bulk of my paycheck goes towards paying someone's debt. So I'm trying to do this as cost effective as possible. Hence why I came here to beg my case to you amazing and wonderfully insightful community members. =>
The general consensus seems to be basically to start with the spark plugs, so that is where I will start on Saturday. Don't be surprised if you see posts of fear between now and then, and utter loss and confusion the day of. Lol.
I hope to take pictures along the way, so as to chronicle my feeble attempts of becoming mechanically self-sufficient. If niching else, it will give you all something to laugh about for the weekend.
Thread Starter
Newbie
Joined: Feb 2011
Posts: 18
Likes: 0
From: Oceanside, CA
Year: 2000
Model: Cherokee
Engine: 4.0L 6 cyl
Such a wealth of knowledge... and DIAGRAMS!!
/happy dance
I am a very visual learner, so that is going to be a MAJOR help... thank you, all of you!
It probably sounds pathetic, but I'm sort of actually looking forward to getting under the hood now. I doubt I'll get it, let alone get it right, on the first attempt tomorrow... but I'm going to try my hardest.
/happy dance
I am a very visual learner, so that is going to be a MAJOR help... thank you, all of you!
It probably sounds pathetic, but I'm sort of actually looking forward to getting under the hood now. I doubt I'll get it, let alone get it right, on the first attempt tomorrow... but I'm going to try my hardest.
Senior Member
Joined: Jan 2011
Posts: 801
Likes: 1
From: N. IL
Year: 2000
Model: Cherokee
Engine: 4.0
tool and material list:
•NKG V-Power Spark Plugs; ZFR5N; @ Gap .035 (6)
•13mm Socket
• 5/8" Spark Plug Socket
• Ratchet
• Ratchet Extensions
• Torque Wrench
• Flat Head Screwdriver
• Universal Joint Socket
• Anti-seize Compound
• Dielectric grease
•spark plug gap gauge
if you don't have a Torque Wrench your auto parts store may loan you one
dielectric grease on spark plug ceramic end helps seal from moisture, promotes electrical connection and allows for easier install/uninstall of rubber boots.
Anti-seize on spark plug threads keeps threads from getting frozen in engine.
enjoy the adventure!
•NKG V-Power Spark Plugs; ZFR5N; @ Gap .035 (6)
•13mm Socket
• 5/8" Spark Plug Socket
• Ratchet
• Ratchet Extensions
• Torque Wrench
• Flat Head Screwdriver
• Universal Joint Socket
• Anti-seize Compound
• Dielectric grease
•spark plug gap gauge
if you don't have a Torque Wrench your auto parts store may loan you one
dielectric grease on spark plug ceramic end helps seal from moisture, promotes electrical connection and allows for easier install/uninstall of rubber boots.
Anti-seize on spark plug threads keeps threads from getting frozen in engine.
enjoy the adventure!
Last edited by DaddyCat; Feb 11, 2011 at 12:30 PM.
Senior Member
Joined: Jan 2011
Posts: 801
Likes: 1
From: N. IL
Year: 2000
Model: Cherokee
Engine: 4.0
One warning, when you install the new spark plugs they should thread in easily ~6-10 turns. If it feels tight right at the start loosen one full turn and try again.
Thread Starter
Newbie
Joined: Feb 2011
Posts: 18
Likes: 0
From: Oceanside, CA
Year: 2000
Model: Cherokee
Engine: 4.0L 6 cyl
DaddyCat... you're awesome. All of you are awesome.
I think it best to have my ipad down in the engine with me, so I can read this thread through as the insanity ensues. (And to help channel my inner mechanic.)
I think it best to have my ipad down in the engine with me, so I can read this thread through as the insanity ensues. (And to help channel my inner mechanic.)
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
thttp://www.jeep4x4center.com/knowled...ex.htm#servicehere is freepdf instructions here just enter the model and year
Senior Member
Joined: Jan 2011
Posts: 801
Likes: 1
From: N. IL
Year: 2000
Model: Cherokee
Engine: 4.0
Thank you and you're welcome...... lol @ "inner mechanic"
lotus position chanting "oooommmmm"
one thing missing from tool list..... cold beer
lotus position chanting "oooommmmm"
one thing missing from tool list..... cold beer
Last edited by DaddyCat; Feb 11, 2011 at 01:32 PM.
CF Veteran
Joined: Jan 2011
Posts: 1,648
Likes: 0
From: Havana fl
Year: 1995
Model: Cherokee
Engine: 4.0L
+1 x 4 on the cold ones...... You can do it Lady McCoy. This is car repair 101, now if you'd never done anything but change oil and wanted to try to rebuild you auto trans, we might try to stop you, but you will be fine I do believe.
Thread Starter
Newbie
Joined: Feb 2011
Posts: 18
Likes: 0
From: Oceanside, CA
Year: 2000
Model: Cherokee
Engine: 4.0L 6 cyl
thttp://www.jeep4x4center.com/knowled...ex.htm#servicehere is freepdf instructions here just enter the model and year
DaddyCat: do I need to add a "boot puller" to the tools list? Or is there an acceptable substitution?
My late grandfather used to work on fire trucks, and my brother has been my grease monkey since before I learned to drive... so I know the ability must be in me somewhere, right?
On a side note: I've never been one for beer, I'm more of a jager or fruity-girly drinks kind of gal. And I don't think those will help my cause much. lol
Senior Member
Joined: Jan 2011
Posts: 801
Likes: 1
From: N. IL
Year: 2000
Model: Cherokee
Engine: 4.0
no boot puller needed, just pull on the coil rail and the boots all come out (they are attached to the coil rail).
Last edited by DaddyCat; Feb 11, 2011 at 01:41 PM.