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Unread 10-09-2013, 07:30 AM   #1
92utownxj
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1992 XJ Cherokee 
 
Join Date: Sep 2005
Location: Unionville, Indiana
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4.0 difficult to start and won't idle

I searched yesterday and tried a few things last night, but it's still acting up. I have a 1997 Grand Cherokee with the 4.0 and 180,000 miles. I won't start most of the time unless I use the throttle and I have to keep on the throttle to keep it running. If I let off, it dies. I gave it a general tune up since it needed it anyway: plugs, wires, cap, rotor. I took the idle air control valve out last night and cleaned it up really well. There was lots of build up on it. It didn't help though, still stalls out. I don't want to buy parts to throw at it in hopes of fixing it unless I know for sure. Could it be the throttle position sensor on the throttle body? A friend mentioned crankshaft position sensor too.

Any help would be greatly appreciated. Currently my gf is driving my lifted Cherokee on 33s, which she loves, but need to get her Jeep fixed.

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Unread 10-09-2013, 08:39 AM   #2
kensnelling
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1998 ZJ 
 
Join Date: Nov 2012
Location: Broken Arrow, OK
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Quote:
Originally Posted by 92utownxj View Post
I took the idle air control valve out last night and cleaned it up really well. There was lots of build up on it. It didn't help though, still stalls out.
Did you just clean the IAC pintle, or did you pull the throttle body and clean the well it goes into also? Still sounds like a dirty throttle body, or maybe a defective IAC motor.

Ken
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Unread 10-09-2013, 09:11 AM   #3
92utownxj
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1992 XJ Cherokee 
 
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Location: Unionville, Indiana
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I just pulled the IAC and cleaned it. I can pull the whole throttle body and clean it really well. I'll try doing that tonight and see what happens.
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Unread 10-09-2013, 09:25 AM   #4
kensnelling
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Wouldn't be a bad idea to also get a throttle body to manifold gasket also. They've been known to crack when you pull the throttle body off.

Ken
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Unread 10-09-2013, 10:12 AM   #5
92utownxj
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1992 XJ Cherokee 
 
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Location: Unionville, Indiana
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I was going to ask about that. I'll pick one up. I hope the Napa in town has one in stock. Hopefully cleaning the throttle body and everything really well will fix the problem. Thanks.
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Unread 10-09-2013, 10:36 AM   #6
Speedymcracer01
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Sounds like your TPS if you haven't tried yet. After you crank it keep it running " I had to constantly play with the accelerator to get my 98 to move" but if you can get it to go down the road,it will not want to shift out if it is the TPS. The TPS controls when the transmission down shifts,and shifts out into the next gear. So if yours doesn't want to change gears it's a very good possibility you need a TPS. I picked my TPS up from O'Reillys auto parts for around $40. They usually have it in stock
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Unread 10-09-2013, 11:48 AM   #7
92utownxj
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Location: Unionville, Indiana
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So far it drives fine if I can keep it running while at idle. There aren't any issues with shifting or anything.
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Unread 10-09-2013, 01:37 PM   #8
Speedymcracer01
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Ok so it's wanting to die when it's idling. Is that the only time it acts up like that?
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Unread 10-09-2013, 01:45 PM   #9
92utownxj
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1992 XJ Cherokee 
 
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Location: Unionville, Indiana
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That's the only time I've noticed it. Last night I had to work the throttle to get it to start. Then, when I'd let off completely the rpms would drop and die. It didn't sputter or anything, just stalls. It doesn't want to idle at all, but if I hold the throttle open a bit it will maintain a steady rpm without any hesitation. The first time I started it last night with a cold engine it took a few times to get it started, but it did idle perfectly. I shut it off, then it had trouble starting and wouldn't idle.
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Unread 10-15-2013, 10:34 AM   #10
92utownxj
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1992 XJ Cherokee 
 
Join Date: Sep 2005
Location: Unionville, Indiana
Posts: 6
Last week I was able to take off the throttle body and clean it really well. I made sure the IAC was very clean and all the connections were tight. I also cleaned up the battery posts and connections. The first few times I started it I still had to work the throttle for it to run without stalling. The next day it started perfectly and idled great. It's been great ever since so hopefully by doing everything the problem is solved. I'll keep you updated. Thanks for the help.
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Unread 10-15-2013, 12:13 PM   #11
Speedymcracer01
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Glad it's running good now
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