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Throttle sticking?

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Old Jun 26, 2012 | 12:08 AM
  #1  
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From: Wenatchee, WA
Year: 1990
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Engine: 4.0L Renix
Default Throttle sticking?

About every time I drive my Jeep for over 5 or 10 minutes and I stop or put it in park, the RPM's are abnormally high. However, I can punch the pedal quickly and the RPM's drop back down into a normal idle state. What's causing this? It's rather annoying.
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Old Jun 26, 2012 | 12:12 AM
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Originally Posted by shooting sticks
About every time I drive my Jeep for over 5 or 10 minutes and I stop or put it in park, the RPM's are abnormally high. However, I can punch the pedal quickly and the RPM's drop back down into a normal idle state. What's causing this? It's rather annoying.
tps may be going out?
I would try to pull the throttle body and clean it really good as well as the sensors. The butterfly may be getting caught on something or some buildup and when you punch it and let off the peddle the spring snaps it back where it is supposed to be.
I would start by doing whats cheapest and pulling the trottle body and giving it a good cleaning.
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Old Jun 26, 2012 | 12:14 AM
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Originally Posted by sik_xj
tps may be going out?
I would try to pull the throttle body and clean it really good as well as the sensors. The butterfly may be getting caught on something or some buildup and when you punch it and let off the peddle the spring snaps it back where it is supposed to be.
I would start by doing whats cheapest and pulling the trottle body and giving it a good cleaning.
Recently cleaned the tps and tb. Clean as a whistle!
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Old Jun 26, 2012 | 12:32 AM
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Did you take the Tps out to clean it or just clean it through the port holes?
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Old Jun 26, 2012 | 12:55 AM
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Originally Posted by xj_maniac_newb
Did you take the Tps out to clean it or just clean it through the port holes?
Took it out! Any other ideas?
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Old Jun 26, 2012 | 01:23 AM
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Originally Posted by shooting sticks
Took it out! Any other ideas?
maybe the throttle cable from the pedal is hanging up somewhere...or the cruise cable is getting hung up.
or the spring is screwed up on the throttle body...maybe trying to get a buddy that has a throttle body that is the same to see if you could swap on to see if it makes a difference
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Old Jun 26, 2012 | 01:49 AM
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Never a bad idea to lube the throttle cable anyway. If it's not coming back to the stop screw, see what you need to pull/push to let it come home. Bet it's the cable.
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Old Jun 26, 2012 | 01:51 AM
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Cleaning will fix a dirty TPS, but not a worn-out one. It's just a variable resistor, they can develop mechanical problems. I believe there is a test/adjust procedure posted here somewhere.
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Old Jun 26, 2012 | 02:22 AM
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Yea, cruisers TPS adjustment is in my signature, (For Renix), 91 and on don't adjust, if I have that right.
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Old Jun 26, 2012 | 03:01 AM
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I'll examine the cables closely tomorrow after work. Any spots you can think of off your heads that would like some lubrication?
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Old Jun 30, 2012 | 07:26 PM
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So I checked the throttle cable and it is sticking somewhere causing it to not come all the way to the stop screw. I found a broken plastic piece which I fixed and I thought it fixed the problem since the throttle came all the way back to the stop screw, but I just got off work and when I turned the Jeep on my idle was rock solid at 600 very steady and smooth and when I went up to the next stop light it was at about 900. I can still stomp the throttle and it lowers. What should I lube up!? I put lube at these 3 spots where the wire went into a tube, if that makes sense.
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Old Jun 30, 2012 | 07:57 PM
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OK, check this out. On my 90, the cable housing snaps into the bracket there, then 4 inches or so lower the cable end it's self snaps onto the ball on that bracket. Mine had a small black plastic "sheathing", (sort of like some tendon sheathing I wish I had back). In mine that little black plastic tube around the cable got brittle and broke up. (below the white deal). My symptom was right as I come off idle, it would catch. I disconnected the socket, (it is metal, not the brakeing plastic kind), then I actually fabbed a little pry deal to remove the housing from the bracket. Anyway you will find those clips are front and back.

After it was off I saw, all I neded to do is crunch/shatter the remaining little black plastic tube, (that was around those last few inches of cable). I might have been able to do that with a needle nose without taking it all apart, is was so brittle, it just shattered with pliers.

Anyway, since I had the cable housing end free, I raised it up and applied the "nectar of the gods" (Castrol 30W) and all is fine now. (don't put that stuff on your drill bits or saws, they won't cut).

If you can manage to see or reach that little black tube, just make it gone.

Of course the pivot for your pedal is free, and lubed.
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Old Jun 30, 2012 | 08:01 PM
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Year: 1990
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Originally Posted by DFlintstone
OK, check this out. On my 90, the cable housing snaps into the bracket there, then 4 inches or so lower the cable end it's self snaps onto the ball on that bracket. Mine had a small black plastic "sheathing", (sort of like some tendon sheathing I wish I had back). In mine that little black plastic tube around the cable got brittle and broke up. (below the white deal). My symptom was right as I come off idle, it would catch. I disconnected the socket, (it is metal, not the brakeing plastic kind), then I actually fabbed a little pry deal to remove the housing from the bracket. Anyway you will find those clips are front and back.

After it was off I saw, all I neded to do is crunch/shatter the remaining little black plastic tube, (that was around those last few inches of cable). I might have been able to do that with a needle nose without taking it all apart, is was so brittle, it just shattered with pliers.

Anyway, since I had the cable housing end free, I raised it up and applied the "nectar of the gods" (Castrol 30W) and all is fine now. (don't put that stuff on your drill bits or saws, they won't cut).

If you can manage to see or reach that little black tube, just make it gone.

Of course the pivot for your pedal is free, and lubed.
Got any pictures of this?
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Old Jun 30, 2012 | 11:14 PM
  #14  
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I left my Jeep on and pulled on the throttle to see if it was still catching and it stops bbaaaaaaaaarrrrreeelllyyyy before the stop screw and when I push it that half centimeter the idle lowers by like 300 rpms.. I don't even know what is catching.
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Old Jul 1, 2012 | 09:04 AM
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I wonder if your throttle butterfly stop screw has been screwed with by some "Uncle Bob" at some point. What happens if you disconnect the accelerator cable and work the tB manually? Can you duplicate the symptom? Good way to isolate where the problem is anyway.
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