IACs made of gold now
CF Veteran
Joined: Jul 2011
Posts: 1,045
Likes: 1
From: Oceanside So Cal
Year: 88
Model: Cherokee (XJ)
Engine: 4.0 renix
First off, congratulations on being so thorough.
My buddy replaced the valve spring on his offending cylinder/valve with no luck. It seems that carbon gets hammered between the valve face and seat. He tried Seafoam, BG 44K etc. I advised him to try the following old mechanic's trick and that finally fixed it.
Pretty easy.
Get a cup of water, preferably something like a Dixie cup.
With the air cleaner off, hold the engine RPM at 2000 RPM or higher and dribble the water from the Dixie cup, which you've pinched to look like a spout on top, into the carb or throttle body. Go slowly and the engine will bog a bit. Stop and let it recover. Repeat until the cup is empty.
My buddy replaced the valve spring on his offending cylinder/valve with no luck. It seems that carbon gets hammered between the valve face and seat. He tried Seafoam, BG 44K etc. I advised him to try the following old mechanic's trick and that finally fixed it.
Pretty easy.
Get a cup of water, preferably something like a Dixie cup.
With the air cleaner off, hold the engine RPM at 2000 RPM or higher and dribble the water from the Dixie cup, which you've pinched to look like a spout on top, into the carb or throttle body. Go slowly and the engine will bog a bit. Stop and let it recover. Repeat until the cup is empty.
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Joined: Aug 2011
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
CF Veteran
Joined: Jul 2011
Posts: 1,045
Likes: 1
From: Oceanside So Cal
Year: 88
Model: Cherokee (XJ)
Engine: 4.0 renix
Thread Starter
Member
Joined: Aug 2012
Posts: 171
Likes: 2
From: Atlanta Georgia
Year: 1997
Model: Cherokee
Engine: 4.0L
Ok so Jeep made the trip out to Augusta from Atlanta fine. Had 3/4 tank of gas so I put a full bottle in of the Texchron. Avg about 70 with RPMs at about 2100. Ran fine. Had a event for about 3.5 and it sat. Came out started fine but could feel the roughness back in the idle. Bang CEL back on. Bummer.
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
CF Veteran
Joined: Jul 2012
Posts: 1,395
Likes: 1
From: SD
Year: 1998
Model: Cherokee
Engine: 4.0
I'm still thinking you need to replace the valve springs, at least on that cyl. With mine, I ran the Mopar Comb. Chamber Cleaner, and the code stayed away for awhile, too. When it finally came back, I replaced the springs on the affected cyl, and that cured it. In summary, both the spring replacement and the de-carbonizing are needed. (If you replace the springs, then you may want to do the water treatment one more time.)
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'm still thinking you need to replace the valve springs, at least on that cyl. With mine, I ran the Mopar Comb. Chamber Cleaner, and the code stayed away for awhile, too. When it finally came back, I replaced the springs on the affected cyl, and that cured it. In summary, both the spring replacement and the de-carbonizing are needed. (If you replace the springs, then you may want to do the water treatment one more time.)
Banned
Joined: Oct 2012
Posts: 1,744
Likes: 2
From: USA
Year: 1998
Model: Cherokee
Engine: 4.0L i6
My local dealer charges $119 for the IAC.
So, you just run the engine with the entire intake boot off?
Can this work on cars with a MAF right after the air filter and before the throttle body?
So, you just run the engine with the entire intake boot off?
Can this work on cars with a MAF right after the air filter and before the throttle body?
Last edited by BimmerJeeper; Jan 19, 2013 at 12:31 AM.
CF Veteran
Joined: Dec 2011
Posts: 1,777
Likes: 22
From: PA KOTUFU!
Year: 1998
Engine: 4.0L 162,000
Jeep- Yes.
No . not really. Don't put water or any spray thru the MAF. Maybe could spray just before the TB, but there can't be any air leaks. Seafoam has an adapter/guide for the spray tube to put under the clamp on the TB to seal it and still be able to spray in the Seafoam.
No . not really. Don't put water or any spray thru the MAF. Maybe could spray just before the TB, but there can't be any air leaks. Seafoam has an adapter/guide for the spray tube to put under the clamp on the TB to seal it and still be able to spray in the Seafoam.
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