Having multiple engine issues
Thread Starter
Junior Member
Joined: May 2011
Posts: 43
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From: Cashmere, WA it's by leavenworth
Year: 89 & 91
Model: Cherokee
Engine: 4.0L & 4.0L HO
First off when starting my blue beast the cranking time before it fires up takes longer than it seems it should, when its warm it'll start a bit faster but still slow.
Second when I'm idling it will go from 750 down to 500 for a few seconds a d then pop back to 750
Third when I'm Cruisin along I get a little puh puh every now and then that usually smooths out but comes back..
What I've done so far:
Sea foam in gas tank
Sea foam intake
Tune up along with a brand new distributor and wires plugs cap rotor
New timing chain and gears
Cleaned all electrical plugs and ground points
Sprayed water in engine compartment in search of vacuum leaks... None
Had a friend test my injectors and they turn on and off when they should
I have had this jeep for a while and these issues are drivin me batty, any insight would be greatly appreciated, I'm getting a new exhaust put on tomorrow because currently it's cherry bombed and dumps out in front of the rear axle and sounds like crap. I work nightshift so I don't get a lot of time to fix on this thing, but as previously stated any ideas of where to start or where to go would be awesome. Thank you
Second when I'm idling it will go from 750 down to 500 for a few seconds a d then pop back to 750
Third when I'm Cruisin along I get a little puh puh every now and then that usually smooths out but comes back..
What I've done so far:
Sea foam in gas tank
Sea foam intake
Tune up along with a brand new distributor and wires plugs cap rotor
New timing chain and gears
Cleaned all electrical plugs and ground points
Sprayed water in engine compartment in search of vacuum leaks... None
Had a friend test my injectors and they turn on and off when they should
I have had this jeep for a while and these issues are drivin me batty, any insight would be greatly appreciated, I'm getting a new exhaust put on tomorrow because currently it's cherry bombed and dumps out in front of the rear axle and sounds like crap. I work nightshift so I don't get a lot of time to fix on this thing, but as previously stated any ideas of where to start or where to go would be awesome. Thank you
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Joined: Jan 2012
Posts: 720
Likes: 1
From: vanburen
Year: 1995 &2000
Model: Cherokee
Engine: 4.0
Cel on? If so have it checked for codes then post them here it will help with a diagnosis, but it does sound like o2 sensors and or tps. Also have you checked fuel psi at the rail?
Thread Starter
Junior Member
Joined: May 2011
Posts: 43
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From: Cashmere, WA it's by leavenworth
Year: 89 & 91
Model: Cherokee
Engine: 4.0L & 4.0L HO
Yea I forgot to mention fuel pressure test, it was ok according to the guy who checked it for me. No check engine and even if there was, no one around here can get codes off of the old renix CPU.... My jeep is an 88. Ty for the fast responses, I've hooked my tips to a voltmeter and it seemed ok but I spose it could still be fubar; I believe I have a new o2 sensor just haven't had enough daylight/time to change it! And yes cherry bombs sound like crap IMHO
I'm not used to vehicles with all the emissions garbage on them, so I'm changing the exhaust in case it might be a back pressure issue
I'm not used to vehicles with all the emissions garbage on them, so I'm changing the exhaust in case it might be a back pressure issue
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Thread Starter
Junior Member
Joined: May 2011
Posts: 43
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From: Cashmere, WA it's by leavenworth
Year: 89 & 91
Model: Cherokee
Engine: 4.0L & 4.0L HO
My tb doesn't look dirty at all... And I'm not even sure the engine light works, I'm gonna go outside and flip the key and check real quick :s got a little down time between parts here at work
Thread Starter
Junior Member
Joined: May 2011
Posts: 43
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From: Cashmere, WA it's by leavenworth
Year: 89 & 91
Model: Cherokee
Engine: 4.0L & 4.0L HO
That's a negative on the cel, only lights that come on with key turned to on are emis maint, shift light, washer, and seatbelt.... So I think it must have been on for so long before I bought it that it is now burnt out
CF Veteran
Joined: Nov 2010
Posts: 15,581
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From: some small town oregon
Year: 1989
Model: Cherokee
Engine: 4.0
Originally Posted by freegdr
89 dont have one
Thread Starter
Junior Member
Joined: May 2011
Posts: 43
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From: Cashmere, WA it's by leavenworth
Year: 89 & 91
Model: Cherokee
Engine: 4.0L & 4.0L HO
Funny enough I have a new cps just haven't put it in cus it seems like a pain in the rear to get to it without removing the manifold... And the fuel filter I changed a while back but probably not a bad idea after I seafoamed the gas tank it's probably plugged with more crap
CF Veteran
Joined: Nov 2010
Posts: 15,581
Likes: 8
From: some small town oregon
Year: 1989
Model: Cherokee
Engine: 4.0
Originally Posted by redeyez
Funny enough I have a new cps just haven't put it in cus it seems like a pain in the rear to get to it without removing the manifold... And the fuel filter I changed a while back but probably not a bad idea after I seafoamed the gas tank it's probably plugged with more crap


