High idle after warmed up (88 Jeep Comanche)
 

So I had an issue about 6 months ago with a high idle (about 3000 rpm)
immediately on start-up. That was rectified by taking out and cleaning the
IAC; life was good.

Now it idles fine on start-up, but after the engines warmed up a bit (5
minutes of running), the idle creeps up to about 1500 rpm, and stays there.
Very consistent. I've cleaned the IAC again, and the connectors on both the
IAC and TPS. Am I looking at cleaning the entire throttle body now? Is
that a logical next step? Or is there something else I should be looking at
first?

Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

I would be putting a vacuum gauge on to see if it has a leak I think.

I then would be checking the TPS with a multimeter. It can be tested
live for voltage levels with the engine off, but the key in run or
unplugged with the ohm meter. For volts you would be looking at .2 to
4.8 I believe from closed to open.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Clint wrote:
> So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> immediately on start-up. That was rectified by taking out and cleaning
> the IAC; life was good.
>
> Now it idles fine on start-up, but after the engines warmed up a bit (5
> minutes of running), the idle creeps up to about 1500 rpm, and stays
> there. Very consistent. I've cleaned the IAC again, and the connectors
> on both the IAC and TPS. Am I looking at cleaning the entire throttle
> body now? Is that a logical next step? Or is there something else I
> should be looking at first?
>
> Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

I would be putting a vacuum gauge on to see if it has a leak I think.

I then would be checking the TPS with a multimeter. It can be tested
live for voltage levels with the engine off, but the key in run or
unplugged with the ohm meter. For volts you would be looking at .2 to
4.8 I believe from closed to open.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Clint wrote:
> So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> immediately on start-up. That was rectified by taking out and cleaning
> the IAC; life was good.
>
> Now it idles fine on start-up, but after the engines warmed up a bit (5
> minutes of running), the idle creeps up to about 1500 rpm, and stays
> there. Very consistent. I've cleaned the IAC again, and the connectors
> on both the IAC and TPS. Am I looking at cleaning the entire throttle
> body now? Is that a logical next step? Or is there something else I
> should be looking at first?
>
> Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

I would be putting a vacuum gauge on to see if it has a leak I think.

I then would be checking the TPS with a multimeter. It can be tested
live for voltage levels with the engine off, but the key in run or
unplugged with the ohm meter. For volts you would be looking at .2 to
4.8 I believe from closed to open.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Clint wrote:
> So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> immediately on start-up. That was rectified by taking out and cleaning
> the IAC; life was good.
>
> Now it idles fine on start-up, but after the engines warmed up a bit (5
> minutes of running), the idle creeps up to about 1500 rpm, and stays
> there. Very consistent. I've cleaned the IAC again, and the connectors
> on both the IAC and TPS. Am I looking at cleaning the entire throttle
> body now? Is that a logical next step? Or is there something else I
> should be looking at first?
>
> Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

I would be putting a vacuum gauge on to see if it has a leak I think.

I then would be checking the TPS with a multimeter. It can be tested
live for voltage levels with the engine off, but the key in run or
unplugged with the ohm meter. For volts you would be looking at .2 to
4.8 I believe from closed to open.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Clint wrote:
> So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> immediately on start-up. That was rectified by taking out and cleaning
> the IAC; life was good.
>
> Now it idles fine on start-up, but after the engines warmed up a bit (5
> minutes of running), the idle creeps up to about 1500 rpm, and stays
> there. Very consistent. I've cleaned the IAC again, and the connectors
> on both the IAC and TPS. Am I looking at cleaning the entire throttle
> body now? Is that a logical next step? Or is there something else I
> should be looking at first?
>
> Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

Does this seem to describe how I'm supposed to adjust/test the voltage?
http://wagoneers.com/XJ/tech/TPS-adjustment.html

Similar to this:

I have a1989 factory service manual and it says the
following for manual trans application. On the back of the TPS harness
connector the terminals are marked A, B, and C. While leaving it
plugged in
you will need to back probe the connector with a digital volt/ohm
meter. (
you can stick the leads of the meter in the back of the plug where the
wires
enter without doing any damage). The sensor input voltage is read by
inserting the negative lead in terminal B and positive lead in terminal
A.
Throttle should be completely closed and voltage should read about 5
volts.
(record your reading)
To check sensor output voltage, leave negative wire in
back of
terminal B, switch positive lead to terminal C. Again throttle is to be

completely closed. (record your reading)
To check for proper TPS adjustment, divide the output
voltage
reading by the input voltage reading. The desired ratio is .825 to .835

(.830
desired). If necessary adjust TPS sensor until the correct ratio is
obtained.

Clint

Mike Romain wrote:
> I would be putting a vacuum gauge on to see if it has a leak I think.
>
> I then would be checking the TPS with a multimeter. It can be tested
> live for voltage levels with the engine off, but the key in run or
> unplugged with the ohm meter. For volts you would be looking at .2 to
> 4.8 I believe from closed to open.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> 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)
>
> Clint wrote:
> > So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> > immediately on start-up. That was rectified by taking out and cleaning
> > the IAC; life was good.
> >
> > Now it idles fine on start-up, but after the engines warmed up a bit (5
> > minutes of running), the idle creeps up to about 1500 rpm, and stays
> > there. Very consistent. I've cleaned the IAC again, and the connectors
> > on both the IAC and TPS. Am I looking at cleaning the entire throttle
> > body now? Is that a logical next step? Or is there something else I
> > should be looking at first?
> >
> > Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

Does this seem to describe how I'm supposed to adjust/test the voltage?
http://wagoneers.com/XJ/tech/TPS-adjustment.html

Similar to this:

I have a1989 factory service manual and it says the
following for manual trans application. On the back of the TPS harness
connector the terminals are marked A, B, and C. While leaving it
plugged in
you will need to back probe the connector with a digital volt/ohm
meter. (
you can stick the leads of the meter in the back of the plug where the
wires
enter without doing any damage). The sensor input voltage is read by
inserting the negative lead in terminal B and positive lead in terminal
A.
Throttle should be completely closed and voltage should read about 5
volts.
(record your reading)
To check sensor output voltage, leave negative wire in
back of
terminal B, switch positive lead to terminal C. Again throttle is to be

completely closed. (record your reading)
To check for proper TPS adjustment, divide the output
voltage
reading by the input voltage reading. The desired ratio is .825 to .835

(.830
desired). If necessary adjust TPS sensor until the correct ratio is
obtained.

Clint

Mike Romain wrote:
> I would be putting a vacuum gauge on to see if it has a leak I think.
>
> I then would be checking the TPS with a multimeter. It can be tested
> live for voltage levels with the engine off, but the key in run or
> unplugged with the ohm meter. For volts you would be looking at .2 to
> 4.8 I believe from closed to open.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> 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)
>
> Clint wrote:
> > So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> > immediately on start-up. That was rectified by taking out and cleaning
> > the IAC; life was good.
> >
> > Now it idles fine on start-up, but after the engines warmed up a bit (5
> > minutes of running), the idle creeps up to about 1500 rpm, and stays
> > there. Very consistent. I've cleaned the IAC again, and the connectors
> > on both the IAC and TPS. Am I looking at cleaning the entire throttle
> > body now? Is that a logical next step? Or is there something else I
> > should be looking at first?
> >
> > Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

Does this seem to describe how I'm supposed to adjust/test the voltage?
http://wagoneers.com/XJ/tech/TPS-adjustment.html

Similar to this:

I have a1989 factory service manual and it says the
following for manual trans application. On the back of the TPS harness
connector the terminals are marked A, B, and C. While leaving it
plugged in
you will need to back probe the connector with a digital volt/ohm
meter. (
you can stick the leads of the meter in the back of the plug where the
wires
enter without doing any damage). The sensor input voltage is read by
inserting the negative lead in terminal B and positive lead in terminal
A.
Throttle should be completely closed and voltage should read about 5
volts.
(record your reading)
To check sensor output voltage, leave negative wire in
back of
terminal B, switch positive lead to terminal C. Again throttle is to be

completely closed. (record your reading)
To check for proper TPS adjustment, divide the output
voltage
reading by the input voltage reading. The desired ratio is .825 to .835

(.830
desired). If necessary adjust TPS sensor until the correct ratio is
obtained.

Clint

Mike Romain wrote:
> I would be putting a vacuum gauge on to see if it has a leak I think.
>
> I then would be checking the TPS with a multimeter. It can be tested
> live for voltage levels with the engine off, but the key in run or
> unplugged with the ohm meter. For volts you would be looking at .2 to
> 4.8 I believe from closed to open.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> 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)
>
> Clint wrote:
> > So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> > immediately on start-up. That was rectified by taking out and cleaning
> > the IAC; life was good.
> >
> > Now it idles fine on start-up, but after the engines warmed up a bit (5
> > minutes of running), the idle creeps up to about 1500 rpm, and stays
> > there. Very consistent. I've cleaned the IAC again, and the connectors
> > on both the IAC and TPS. Am I looking at cleaning the entire throttle
> > body now? Is that a logical next step? Or is there something else I
> > should be looking at first?
> >
> > Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

Does this seem to describe how I'm supposed to adjust/test the voltage?
http://wagoneers.com/XJ/tech/TPS-adjustment.html

Similar to this:

I have a1989 factory service manual and it says the
following for manual trans application. On the back of the TPS harness
connector the terminals are marked A, B, and C. While leaving it
plugged in
you will need to back probe the connector with a digital volt/ohm
meter. (
you can stick the leads of the meter in the back of the plug where the
wires
enter without doing any damage). The sensor input voltage is read by
inserting the negative lead in terminal B and positive lead in terminal
A.
Throttle should be completely closed and voltage should read about 5
volts.
(record your reading)
To check sensor output voltage, leave negative wire in
back of
terminal B, switch positive lead to terminal C. Again throttle is to be

completely closed. (record your reading)
To check for proper TPS adjustment, divide the output
voltage
reading by the input voltage reading. The desired ratio is .825 to .835

(.830
desired). If necessary adjust TPS sensor until the correct ratio is
obtained.

Clint

Mike Romain wrote:
> I would be putting a vacuum gauge on to see if it has a leak I think.
>
> I then would be checking the TPS with a multimeter. It can be tested
> live for voltage levels with the engine off, but the key in run or
> unplugged with the ohm meter. For volts you would be looking at .2 to
> 4.8 I believe from closed to open.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> 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)
>
> Clint wrote:
> > So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> > immediately on start-up. That was rectified by taking out and cleaning
> > the IAC; life was good.
> >
> > Now it idles fine on start-up, but after the engines warmed up a bit (5
> > minutes of running), the idle creeps up to about 1500 rpm, and stays
> > there. Very consistent. I've cleaned the IAC again, and the connectors
> > on both the IAC and TPS. Am I looking at cleaning the entire throttle
> > body now? Is that a logical next step? Or is there something else I
> > should be looking at first?
> >
> > Clint

Re: High idle after warmed up (88 Jeep Comanche)
 

Does this seem to describe how I'm supposed to adjust/test the voltage?
http://wagoneers.com/XJ/tech/TPS-adjustment.html

Similar to this:

I have a1989 factory service manual and it says the
following for manual trans application. On the back of the TPS harness
connector the terminals are marked A, B, and C. While leaving it
plugged in
you will need to back probe the connector with a digital volt/ohm
meter. (
you can stick the leads of the meter in the back of the plug where the
wires
enter without doing any damage). The sensor input voltage is read by
inserting the negative lead in terminal B and positive lead in terminal
A.
Throttle should be completely closed and voltage should read about 5
volts.
(record your reading)
To check sensor output voltage, leave negative wire in
back of
terminal B, switch positive lead to terminal C. Again throttle is to be

completely closed. (record your reading)
To check for proper TPS adjustment, divide the output
voltage
reading by the input voltage reading. The desired ratio is .825 to .835

(.830
desired). If necessary adjust TPS sensor until the correct ratio is
obtained.

Clint

Mike Romain wrote:
> I would be putting a vacuum gauge on to see if it has a leak I think.
>
> I then would be checking the TPS with a multimeter. It can be tested
> live for voltage levels with the engine off, but the key in run or
> unplugged with the ohm meter. For volts you would be looking at .2 to
> 4.8 I believe from closed to open.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> 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)
>
> Clint wrote:
> > So I had an issue about 6 months ago with a high idle (about 3000 rpm)
> > immediately on start-up. That was rectified by taking out and cleaning
> > the IAC; life was good.
> >
> > Now it idles fine on start-up, but after the engines warmed up a bit (5
> > minutes of running), the idle creeps up to about 1500 rpm, and stays
> > there. Very consistent. I've cleaned the IAC again, and the connectors
> > on both the IAC and TPS. Am I looking at cleaning the entire throttle
> > body now? Is that a logical next step? Or is there something else I
> > should be looking at first?
> >
> > Clint