low idle warm 90 jeep 4.0
03-19-2006, 04:01 PM
#31
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
The early 4.0's had EGR's but they dropped them at some point. I know
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
03-19-2006, 04:01 PM
#32
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
The early 4.0's had EGR's but they dropped them at some point. I know
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
03-19-2006, 04:01 PM
#33
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
The early 4.0's had EGR's but they dropped them at some point. I know
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
the 87 - 89 XJ/MJ using the Renix computer had them - I've cleaned
mine a couple of times.
My MJ had real idle problems and curing them was a step by step
process. Cleaning the throttle body made a big difference (don't
forget the MAP sensor port!), cleaning the connectors also helped but
the last little bit of surge/die coming to a stop persisted until I
changed out the O2 sensor. It tested good, but the tail pipe said it
was idling rich (black soot, black smoke accelerating from idle when
hot) so I changed the sensor. Now all I have to do is clean the
connectors every so often.
On Sun, 19 Mar 2006 19:56:57 UTC "JD Adams" <JDAdams@Softcom.Net>
wrote:
> You're right, Mike. No EGR at all on my rig, and it's probably the
> same on all 4.0's. No wonder it runs so well. EGR is the
> technological equivalance of throwing a wet blanket on a fire, and
> they're difficult to clean when they get gummed up. Smog check techs
> love 'em though; they're good for retest business.
>
> I'm going to put my money on the TPS and a dirty throttle body. Some
> older computers will throw a code for a low TPS signal, but on a '90,
> it's doubtful. Another symptom of TPS failure is an automatic
> transmission OD that keeps dropping in and out when cruising. One
> could hook up a DVM and check it manually, but they're cheap enough
> that replacement makes more sense.
>
> Let us know what you find, Harry.
>
> -JD
>
--
Will Honea
03-19-2006, 06:18 PM
#34
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
Hi Guys:
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
03-19-2006, 06:18 PM
#35
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
Hi Guys:
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
03-19-2006, 06:18 PM
#36
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
Hi Guys:
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
03-19-2006, 06:18 PM
#37
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
Hi Guys:
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
Thanks for the good info. It's been too cold and windy for me today
to do too much, but I did tap into the O2 sensor and that seems pretty
non-responsive. The voltage slowly drops from about .45 to .3 volts,
motor still running and no engine lights. Shouldn't it be closer to
..5V? Even with that, it seems to run fine after its ran a few minutes.
Humm. Maybe that engine light is burnt out. Any quick ways to check
for codes, with a laptop or something?
Thanks!
Harry
03-19-2006, 06:30 PM
#38
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
90 XJ 4.0 does indeed have EGR. Just like your 88.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.
03-19-2006, 06:30 PM
#39
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
90 XJ 4.0 does indeed have EGR. Just like your 88.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.
03-19-2006, 06:30 PM
#40
Guest
Posts: n/a
Re: low idle warm 90 jeep 4.0
90 XJ 4.0 does indeed have EGR. Just like your 88.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.
In message <441AF396.83C2B581@sympatico.ca>, "Mike Romain" wrote:
>The 4.0 doesn't have an EGR, just a CCV. When it's tube plugs, oil
>blows into the air filter.
>
>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)
>
>JD Adams wrote:
>>
>> How long has it been since you've cleaned the throttle body? Most
>> don't ever do it at all. It could be a PCV valve that is damaged and
>> has dropped the valve portion down into the engine creating a big
>> vacuum leak, a really dirty throttle body or a bad spot on the TPS.
>> When you clean out the TB, use a very soft toothbrush and a soft cloth,
>> along with TB-friendly cleaner, not carb cleaner. Work with the engine
>> OFF, and take your time cleaning all the gunk off the sides and the
>> butterfly valve.
>>
>> While you're in there, pull your EGR valve and give that a good
>> cleaning as well. Sometimes they get so gunked up that they stick
>> open, creating a vaccum leak.
>>
>> Also, on those TPS's, aftermarket units are junk. Buy only an OEM
>> replacement. Same goes for the EGR valve, if you ever need to swap it
>> out. I found this all out the hard way.