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backfire thru the intake

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Old 06-24-2009 | 06:17 PM
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From: eaton ohio
Year: 93
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Default backfire thru the intake

just like the title says, any idea what it could be or what it usually is when it does this
Old 06-24-2009 | 07:52 PM
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From: Stafford,VA
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back-firing thru the intake is normally a sign of timing out of wack.......
Old 06-24-2009 | 08:03 PM
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but you cant time the 4.0 can you? the cps controls all that right?
Old 06-24-2009 | 08:10 PM
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I have seen the Distributor gears wear thin causing pops and misses.

Last edited by 98 JeepJeep; 06-24-2009 at 08:17 PM.
Old 06-24-2009 | 08:15 PM
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and how do i go about adjusting that and checking the gears?
Old 06-24-2009 | 08:24 PM
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Originally Posted by claygrassmann
and how do i go about adjusting that and checking the gears?
Ign timing for the 4.0 is none adjustable.....
Here is what i normally do for a condition like yours

1. check plugs/wires/cap/rotor.
2.Check fuel pressure.
3.for removal of the Dist(if you decide to pull it) you need to mark the base of dist and the block so it goes in exactly like it came out...then next mark the rotor point to the side of the dist. to insure it is pointing in the right spot. remove dist hold down/wires then pull it out....
Old 06-24-2009 | 08:27 PM
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that sounds easy enough and i got a buddy that went to UTI so i think if i eff it up he could fix it. distributers are cheap enough i might just go ahead and do that, what should my fuel psi be at? what do i need to check that?
Old 06-24-2009 | 08:36 PM
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Being that you have a 95 and earlier you should have a schrader valve on your fuel rail....kinda looks like a big valve stem....should have a cap on it. that is where your gonna hook up a fuel pressure guage(0-60psi). and since you have a vacuum asst regulator you should see 31 with line on and 39psi with it off.
Old 06-24-2009 | 08:39 PM
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dude are you a mechanic? or just know that much about jeeps lol

would this work?

http://www.sears.com/shc/s/p_10153_1...0070921x00003a

Last edited by claygrassmann; 06-24-2009 at 08:41 PM.
Old 06-24-2009 | 08:42 PM
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Originally Posted by claygrassmann
dude are you a mechanic? or just know that much about jeeps lol
I am a diesel mechanic during the day....work on the mustang and jeep as a hobby. when im not fixing everyone elses cars around the neighborhood.......
Old 06-24-2009 | 08:43 PM
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Originally Posted by claygrassmann
thats the one i have....it will work on any fuel pressure system that uses a schrader valve......
Old 06-24-2009 | 08:45 PM
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score thanks for the help man i really appreciate it
Old 06-24-2009 | 11:56 PM
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This is my story.https://www.cherokeeforum.com/showth...light=backfire
Old 07-15-2009 | 12:51 AM
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I am having the same issue as this. What ended up being the resolve to your issue?

I have new plugs, wires, dist cap, rotor.... Missing/Backfiring under heavy accel and around 1800 rpm.
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