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Jeep Wrangler High Idle Problem



 
 
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  #1  
Old August 13th 07, 02:07 AM posted to rec.autos.makers.jeep+willys
97tjMike
external usenet poster
 
Posts: 73
Default Jeep Wrangler High Idle Problem

Hello Everyone:

I have a 97 TJ and 95% of the time it idles perfectly. However, about
5% of the time, usually when the vehicle has been run for more than 20
minutes or so, the idle in neutral or park will shoot up to between
1200 and 1500 RPM. The only way to get it to stop is to put the
vehicle into gear or to restart the car. If I restart it, it will not
happen for a while, but it eventually comes back. The TPS was recently
replaced, and I just replaced the idle air control valve, thinking
this may have been the problem, but it still has the same effect. I'm
thinking now that it may be the coolant temperature sensor (something
wacky when the engine is hotter making the vehicle run at higher
speeds??). Any suggestions? I'm hoping its not my computer...

Ads
  #2  
Old August 13th 07, 02:42 AM posted to rec.autos.makers.jeep+willys
Jeff DeWitt
external usenet poster
 
Posts: 175
Default Jeep Wrangler High Idle Problem

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>


Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt
  #3  
Old August 13th 07, 02:42 AM posted to rec.autos.makers.jeep+willys
Jeff DeWitt
external usenet poster
 
Posts: 175
Default Jeep Wrangler High Idle Problem

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>


Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt
  #4  
Old August 13th 07, 03:00 AM posted to rec.autos.makers.jeep+willys
97tjMike
external usenet poster
 
Posts: 73
Default Jeep Wrangler High Idle Problem

On Aug 12, 9:42 pm, Jeff DeWitt > wrote:
> 97tjMike wrote:
> > Hello Everyone:

>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...

>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt


Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

  #5  
Old August 13th 07, 03:00 AM posted to rec.autos.makers.jeep+willys
97tjMike
external usenet poster
 
Posts: 73
Default Jeep Wrangler High Idle Problem

On Aug 12, 9:42 pm, Jeff DeWitt > wrote:
> 97tjMike wrote:
> > Hello Everyone:

>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...

>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt


Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

  #6  
Old August 13th 07, 06:04 PM posted to rec.autos.makers.jeep+willys
Will Honea[_1_]
external usenet poster
 
Posts: 552
Default Jeep Wrangler High Idle Problem

97tjMike wrote:

> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...


Clean the TPS connector. Go to an electronics parts store and buy some
contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
disconnect several times, blow dry, then use some dielectric grease on the
the connector seal ring to keep moisture out.

--
Will Honea
  #7  
Old August 13th 07, 06:47 PM posted to rec.autos.makers.jeep+willys
Mike Romain
external usenet poster
 
Posts: 3,758
Default Jeep Wrangler High Idle Problem

Will Honea wrote:
> 97tjMike wrote:
>
>> Hello Everyone:
>>
>> I have a 97 TJ and 95% of the time it idles perfectly. However, about
>> 5% of the time, usually when the vehicle has been run for more than 20
>> minutes or so, the idle in neutral or park will shoot up to between
>> 1200 and 1500 RPM. The only way to get it to stop is to put the
>> vehicle into gear or to restart the car. If I restart it, it will not
>> happen for a while, but it eventually comes back. The TPS was recently
>> replaced, and I just replaced the idle air control valve, thinking
>> this may have been the problem, but it still has the same effect. I'm
>> thinking now that it may be the coolant temperature sensor (something
>> wacky when the engine is hotter making the vehicle run at higher
>> speeds??). Any suggestions? I'm hoping its not my computer...

>
> Clean the TPS connector. Go to an electronics parts store and buy some
> contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
> disconnect several times, blow dry, then use some dielectric grease on the
> the connector seal ring to keep moisture out.
>


Yup, replacing parts only cleans 'half' the connection.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
  #8  
Old August 14th 07, 02:10 AM posted to rec.autos.makers.jeep+willys
97tjMike
external usenet poster
 
Posts: 73
Default Jeep Wrangler High Idle Problem

How would the TPS affect idle speed? From my understanding, it is just
a sending unit, meaning it can only give information to the PCM but
cannot receive and therefore manipulate any settings.

On Aug 13, 1:47 pm, Mike Romain > wrote:
> Will Honea wrote:
> > 97tjMike wrote:

>
> >> Hello Everyone:

>
> >> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> >> 5% of the time, usually when the vehicle has been run for more than 20
> >> minutes or so, the idle in neutral or park will shoot up to between
> >> 1200 and 1500 RPM. The only way to get it to stop is to put the
> >> vehicle into gear or to restart the car. If I restart it, it will not
> >> happen for a while, but it eventually comes back. The TPS was recently
> >> replaced, and I just replaced the idle air control valve, thinking
> >> this may have been the problem, but it still has the same effect. I'm
> >> thinking now that it may be the coolant temperature sensor (something
> >> wacky when the engine is hotter making the vehicle run at higher
> >> speeds??). Any suggestions? I'm hoping its not my computer...

>
> > Clean the TPS connector. Go to an electronics parts store and buy some
> > contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
> > disconnect several times, blow dry, then use some dielectric grease on the
> > the connector seal ring to keep moisture out.

>
> Yup, replacing parts only cleans 'half' the connection.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
> (More Off Road album links at bottom of the view page)



  #9  
Old August 14th 07, 03:24 AM posted to rec.autos.makers.jeep+willys
c[_1_]
external usenet poster
 
Posts: 173
Default Jeep Wrangler High Idle Problem

The PCM uses the signals it receives from the TPS to adjust other
systems on the engine. I would also recommend cleaning the IAC valve and
connector. If it is sticking it can raise the idle speed up.

97tjMike wrote:
> How would the TPS affect idle speed? From my understanding, it is just
> a sending unit, meaning it can only give information to the PCM but
> cannot receive and therefore manipulate any settings.
>
> On Aug 13, 1:47 pm, Mike Romain > wrote:
>> Will Honea wrote:
>>> 97tjMike wrote:
>>>> Hello Everyone:
>>>> I have a 97 TJ and 95% of the time it idles perfectly. However, about
>>>> 5% of the time, usually when the vehicle has been run for more than 20
>>>> minutes or so, the idle in neutral or park will shoot up to between
>>>> 1200 and 1500 RPM. The only way to get it to stop is to put the
>>>> vehicle into gear or to restart the car. If I restart it, it will not
>>>> happen for a while, but it eventually comes back. The TPS was recently
>>>> replaced, and I just replaced the idle air control valve, thinking
>>>> this may have been the problem, but it still has the same effect. I'm
>>>> thinking now that it may be the coolant temperature sensor (something
>>>> wacky when the engine is hotter making the vehicle run at higher
>>>> speeds??). Any suggestions? I'm hoping its not my computer...
>>> Clean the TPS connector. Go to an electronics parts store and buy some
>>> contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
>>> disconnect several times, blow dry, then use some dielectric grease on the
>>> the connector seal ring to keep moisture out.

>> Yup, replacing parts only cleans 'half' the connection.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
>> (More Off Road album links at bottom of the view page)

>
>

  #10  
Old August 14th 07, 02:58 PM posted to rec.autos.makers.jeep+willys
Mike Romain
external usenet poster
 
Posts: 3,758
Default Jeep Wrangler High Idle Problem

The TPS is a resistance based switch just like a volume control. You
can even test it with a multimeter set on ohms or live with the meter
set on volts.

If it has a bad connection, this connection has a resistance factor that
isn't supposed to be there or an arcing issue which causes surges.

When ours got a dirty connection, it would usually stall at the first
stop and get stuck on a 1500 to 2000 rpm fast idle. We were told back
in the 90's that we needed a new TPS in our Cherokee, We just retired
the Cherokee recently with that same 'dead' TPS in it....

All the computer sensors are very low power items that are very touchy
about their connections.

A spray can of electronic contact cleaner will be a very good friend to
you as the Jeep gets older. It will sure save you money, because
changing out parts only fixes 'half' the connection...

Mike

97tjMike wrote:
> How would the TPS affect idle speed? From my understanding, it is just
> a sending unit, meaning it can only give information to the PCM but
> cannot receive and therefore manipulate any settings.
>
> On Aug 13, 1:47 pm, Mike Romain > wrote:
>> Will Honea wrote:
>>> 97tjMike wrote:
>>>> Hello Everyone:
>>>> I have a 97 TJ and 95% of the time it idles perfectly. However, about
>>>> 5% of the time, usually when the vehicle has been run for more than 20
>>>> minutes or so, the idle in neutral or park will shoot up to between
>>>> 1200 and 1500 RPM. The only way to get it to stop is to put the
>>>> vehicle into gear or to restart the car. If I restart it, it will not
>>>> happen for a while, but it eventually comes back. The TPS was recently
>>>> replaced, and I just replaced the idle air control valve, thinking
>>>> this may have been the problem, but it still has the same effect. I'm
>>>> thinking now that it may be the coolant temperature sensor (something
>>>> wacky when the engine is hotter making the vehicle run at higher
>>>> speeds??). Any suggestions? I'm hoping its not my computer...
>>> Clean the TPS connector. Go to an electronics parts store and buy some
>>> contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
>>> disconnect several times, blow dry, then use some dielectric grease on the
>>> the connector seal ring to keep moisture out.

>> Yup, replacing parts only cleans 'half' the connection.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's - Gone to the rust pile...
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
>> (More Off Road album links at bottom of the view page)

>
>

 




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