all muffler and exhaust questions go here!!!!!!
CF Veteran
Joined: May 2011
Posts: 2,135
Likes: 1
From: Santa Rosa, California
Year: 1987 Comanche,1990
Model: Cherokee
Engine: 4.0L Renix
CF Veteran
Joined: Nov 2011
Posts: 2,433
Likes: 6
From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
Hello -- from my 1989 Jeep Exhaust High Temp Post....to Muffler/Exhaust Expert
Hope we can solve this problem.
I have a 1989 Jeep Laredo...6 cyl, 4.0 liter. Old but I love it.
Recently, have had trouble starting after I take it out to store and then come back to drive it again.
On 2 occassions, the car was running at 40MPH and completley shut down...no RPM
Last time it happened, it back fired and flames came out of exhaust pipe.
When I got to side of the road, there was a fire under the car...above muffler...burning the under coating and hot enough to get carpet to smolder. Fire went out. Ever heard that hppen before?
Cat converter is relativley new...20K
Local mechnic tested the O2 sensor and said it is suppose to range 0.1 to 1.0 volts but was reading 2.5 volts and I was told that sensor was calling for more fuel. Does that make sense given that high reading?
Does this car have an Check Engine Alert when something like O2 sensor fails and/or it gets hot like that.
Was lucky this didn't go up in flames, I guess.
Any input from the forum welcomed.....rich (Coloado)
Hope we can solve this problem.
I have a 1989 Jeep Laredo...6 cyl, 4.0 liter. Old but I love it.
Recently, have had trouble starting after I take it out to store and then come back to drive it again.
On 2 occassions, the car was running at 40MPH and completley shut down...no RPM
Last time it happened, it back fired and flames came out of exhaust pipe.
When I got to side of the road, there was a fire under the car...above muffler...burning the under coating and hot enough to get carpet to smolder. Fire went out. Ever heard that hppen before?
Cat converter is relativley new...20K
Local mechnic tested the O2 sensor and said it is suppose to range 0.1 to 1.0 volts but was reading 2.5 volts and I was told that sensor was calling for more fuel. Does that make sense given that high reading?
Does this car have an Check Engine Alert when something like O2 sensor fails and/or it gets hot like that.
Was lucky this didn't go up in flames, I guess.
Any input from the forum welcomed.....rich (Coloado)
Hello -- from my 1989 Jeep Exhaust High Temp Post....to Muffler/Exhaust Expert
Hope we can solve this problem.
I have a 1989 Jeep Laredo...6 cyl, 4.0 liter. Old but I love it.
Recently, have had trouble starting after I take it out to store and then come back to drive it again.
On 2 occassions, the car was running at 40MPH and completley shut down...no RPM
Last time it happened, it back fired and flames came out of exhaust pipe.
When I got to side of the road, there was a fire under the car...above muffler...burning the under coating and hot enough to get carpet to smolder. Fire went out. Ever heard that hppen before?
Cat converter is relativley new...20K
Local mechnic tested the O2 sensor and said it is suppose to range 0.1 to 1.0 volts but was reading 2.5 volts and I was told that sensor was calling for more fuel. Does that make sense given that high reading?
Does this car have an Check Engine Alert when something like O2 sensor fails and/or it gets hot like that.
Was lucky this didn't go up in flames, I guess.
Any input from the forum welcomed.....rich (Coloado)
Hope we can solve this problem.
I have a 1989 Jeep Laredo...6 cyl, 4.0 liter. Old but I love it.
Recently, have had trouble starting after I take it out to store and then come back to drive it again.
On 2 occassions, the car was running at 40MPH and completley shut down...no RPM
Last time it happened, it back fired and flames came out of exhaust pipe.
When I got to side of the road, there was a fire under the car...above muffler...burning the under coating and hot enough to get carpet to smolder. Fire went out. Ever heard that hppen before?
Cat converter is relativley new...20K
Local mechnic tested the O2 sensor and said it is suppose to range 0.1 to 1.0 volts but was reading 2.5 volts and I was told that sensor was calling for more fuel. Does that make sense given that high reading?
Does this car have an Check Engine Alert when something like O2 sensor fails and/or it gets hot like that.
Was lucky this didn't go up in flames, I guess.
Any input from the forum welcomed.....rich (Coloado)
Last tune up?
Test the CPS. You can test it from the engine bay. Just unplug it. Any resistance, it's bad. Plugs into bell housing, then connects by valve cover.
Last edited by CrawlerXJ; Jul 24, 2012 at 08:27 PM.
Thread Starter
::Regional Moderator::
Joined: Aug 2011
Posts: 4,742
Likes: 10
From: Jacksonville, NC
Year: 1993
Model: Cherokee
Engine: I6 4.0L HO
Originally Posted by CrawlerYJ
I don't think on the '89 you have that. It's renix if I remember.
Last tune up?
Test the CPS. You can test it from the engine bay. Just unplug it. Any resistance, it's bad. Plugs into bell housing, then connects by valve cover.
$50
http://www.oreillyauto.com/site/c/de...=oxygen+sensor
Last edited by CrawlerXJ; Jul 24, 2012 at 08:41 PM.
Thread Starter
::Regional Moderator::
Joined: Aug 2011
Posts: 4,742
Likes: 10
From: Jacksonville, NC
Year: 1993
Model: Cherokee
Engine: I6 4.0L HO
Originally Posted by CrawlerYJ
Mechanics are always right. There you go. OP problem is solved.
$50
http://www.oreillyauto.com/site/c/de...=oxygen+sensor
Lol idk had a long day.
But 2 things would cause that. A bad cat or running super rich.
And a cat with 20k isnt what i would expect. But yes o2 at 2.5 volts bad soo bad.
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
you guys want to help me with my exhaust/performance? just PM'd with another member on here and this is what we came up with
1993 xj 4.0
intake manifold heat shield/ relocate IAT sensor
install a 1997 fuel pressure regulator
wrap my header
2.5" mandrel bent down pipe
8-12" section of flex pipe
2.5" evans cat from autozone (gotta be CA legal)
2.5" pipe
2.5" flowmaster super 40 dumped
1993 xj 4.0
intake manifold heat shield/ relocate IAT sensor
install a 1997 fuel pressure regulator
wrap my header
2.5" mandrel bent down pipe
8-12" section of flex pipe
2.5" evans cat from autozone (gotta be CA legal)
2.5" pipe
2.5" flowmaster super 40 dumped
Thread Starter
::Regional Moderator::
Joined: Aug 2011
Posts: 4,742
Likes: 10
From: Jacksonville, NC
Year: 1993
Model: Cherokee
Engine: I6 4.0L HO
Originally Posted by Atmos
you guys want to help me with my exhaust/performance? just PM'd with another member on here and this is what we came up with
1993 xj 4.0
intake manifold heat shield/ relocate IAT sensor
install a 1997 fuel pressure regulator
wrap my header
2.5" mandrel bent down pipe
8-12" section of flex pipe
2.5" evans cat from autozone (gotta be CA legal)
2.5" pipe
2.5" flowmaster super 40 dumped
1993 xj 4.0
intake manifold heat shield/ relocate IAT sensor
install a 1997 fuel pressure regulator
wrap my header
2.5" mandrel bent down pipe
8-12" section of flex pipe
2.5" evans cat from autozone (gotta be CA legal)
2.5" pipe
2.5" flowmaster super 40 dumped
And a 4.2 stroker
jk jk but that set up is good.
Thread Starter
::Regional Moderator::
Joined: Aug 2011
Posts: 4,742
Likes: 10
From: Jacksonville, NC
Year: 1993
Model: Cherokee
Engine: I6 4.0L HO
Originally Posted by CrawlerYJ
I posted a link around here with dyno charts. I think those mufflers are close.
http://www.mustang50magazine.com/tec...t/viewall.html
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
I like the flowmaster it's all preference and nothing is really going to significantly help this 4.0 anyway
I dont care about the numbers I just want it to breathe
so there's nothing you guys would change on my plans? add? I dont want to do this twice
other upgrades will include cowl induction, ironman motor mounts, 62mm bored tb, 22lb injectors, and water proofed
I dont care about the numbers I just want it to breathe
so there's nothing you guys would change on my plans? add? I dont want to do this twice
other upgrades will include cowl induction, ironman motor mounts, 62mm bored tb, 22lb injectors, and water proofed


