1988 Comanche issue..
03-19-2013, 06:57 PM
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1988 Comanche issue..
I just began having a Issue with my Comanche yesterday, It cranked fine a couple time's parked it came back to crank it later and nothing, wouldnt turn over wouldnt do anything. finally after fiddling with the key a little i got it to turn over and crank... sorta, truck will crank and run with the key turned forward in the "start" position, it will rev up and all. but as soon as you release it to the "run" position it shut's off immediately. It is hit and miss on it turning over thou, it may turn over this time but take 10 more tries before it turn's over again, also the fuel pump use to come on when the key was turned to the run position for a few seconds to build up the initial pressure, it does not do that now, it only turns on when you go to the start position with the key, and when you release it to the run position it shuts off. I have not checked pressure on it, but it will crank the truck fine aslong as the key is turned forward, you can back off the key a little with out releasing it all the way and the starter disengages and it continues to run until you release the key all the way.
any idea's on thing's to check? before someone says the ignition switch is out of adjustment, i took it off and operated it manually and it does the same thing, when it will actually turn the truck over, is it bad? I tried another one off a 87 jeep i have that has been setting probably a year and it does the same thing....
any idea's on thing's to check? before someone says the ignition switch is out of adjustment, i took it off and operated it manually and it does the same thing, when it will actually turn the truck over, is it bad? I tried another one off a 87 jeep i have that has been setting probably a year and it does the same thing....
03-19-2013, 10:26 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
On the driver's side inner fender is a fuel pump ballast resistor. See if the connectors are loose on either end.
Got a voltmeter?
Got a voltmeter?
03-20-2013, 10:26 AM
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Year: 1991
Model: Cherokee
Engine: 4.0
If your 88 MJ steering column is anything like mine (91 XJ)...it has the actual ignition switch located at the base of the column...it is actuated by a rod that runs down the column from the key. It is common for the rack mechanism at the back of the key to fail and cause problems similar to yours. The actuator rack or sector gear may be broken. Any decent auto parts store will stock these parts.
03-20-2013, 12:15 PM
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I dropped the column and took the ignition switch off the rod an operated it manually with a screw driver. no change, so i switched it with one from a 87 i has that was setting for about a year. It did the same way.
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03-20-2013, 04:39 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Fuel pump relay?
I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a good electronics cleaner, visually inspecting the terminals making sure they haven’t retracted into the plastic holder, and then plugging it back together. There’s a critical 10-pin connector for the front lighting system located in front of the air cleaner and behind the left headlight assembly. Don’t miss that one
. Also be sure that the connectors to the ballast resistor mounted near the air cleaner housing are clean and tight.
ALL of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then plug them back in. I do this on every Renix Jeep I purchase or work on for someone else.
Revised 07/23/2012
I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a good electronics cleaner, visually inspecting the terminals making sure they haven’t retracted into the plastic holder, and then plugging it back together. There’s a critical 10-pin connector for the front lighting system located in front of the air cleaner and behind the left headlight assembly. Don’t miss that one
. Also be sure that the connectors to the ballast resistor mounted near the air cleaner housing are clean and tight.
ALL of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then plug them back in. I do this on every Renix Jeep I purchase or work on for someone else.
Revised 07/23/2012
03-20-2013, 06:56 PM
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well, got to testing power to the ignition switch and nothing to it has power, I cant seem to locate a diagram of the ignition switch plug's so im not sure which is supposed to have power but i assume one of them must have constant power...
03-20-2013, 10:15 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Ignition switch gets it's power from a red wire that goes through connector c100 from fuse link F (green) off the start relay.
C100 is left of the master cylinder on the dash.
C100 is left of the master cylinder on the dash.
03-20-2013, 11:48 PM
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Year: 90,84
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Engine: 4.0,2.5
Hey Larry...you might have two issues. If you hold the key over, and jiggle the shifter in park or neutral and it starts, it's your NSS. http://bc4x4.com/tech/2010/jeep-neut...ty-switch-nss/
Just a thought there. Then try swapping your second and fourth relays, in that row of four. I guess that second fuel pump relay does more than just fuel, and sticking the AC relay there might tell you something. The blade connections themselves are more suspect than the relay, as Cruiser mentioned.
Not to disagree or distract from the advise above, but both those tests can be done in a minute or two...
Just a thought there. Then try swapping your second and fourth relays, in that row of four. I guess that second fuel pump relay does more than just fuel, and sticking the AC relay there might tell you something. The blade connections themselves are more suspect than the relay, as Cruiser mentioned.
Not to disagree or distract from the advise above, but both those tests can be done in a minute or two...
03-21-2013, 06:36 AM
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Year: 1990
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03-21-2013, 10:29 AM
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Year: 1988
Model: Cherokee
Engine: AMC242
Had the same Sx on my 88 a few years back.
Replaced the ignition switch (atop the column, down by the firewall. Standard GM part atop a GM column) and alles gut!
Probably $20-25, still. BorgWarner or ACDelco are both good brands, and should be readily available. If you can't get either of those, Standard Motor Parts is usually pretty good as well.
Replaced the ignition switch (atop the column, down by the firewall. Standard GM part atop a GM column) and alles gut!
Probably $20-25, still. BorgWarner or ACDelco are both good brands, and should be readily available. If you can't get either of those, Standard Motor Parts is usually pretty good as well.