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87 Jeep Cherokee Laredo 4.0L Vacuum Questions



 
 
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  #1  
Old July 11th 05, 08:36 AM
JKnapp
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Posts: n/a
Default 87 Jeep Cherokee Laredo 4.0L Vacuum Questions

I recently purchased this vehicle and am not having the greatest of
luck with it. for 1 I think I need to clean the CPS Connector. but as
far as the vacuum problem down on the axle I can find where two of the
vacuum lines goto to engage the 4x4, but there is a third line that I
am unable to figue out where it goes. I believe it is the white line.
the other problem that I am having is at idle it will barely have
enough vacuum at idle to divert the air to the vent when I have the
A/C turned on. then when I accel when I get up to about 1500 RPM I
loose the vacuum and the Defroster is what the A/C then comes through.
If I go back to idle It goes back to the vent sometimes. I did tape
off the line underneth by the axle incase that was the problem but
still acts the same. any ideas?

Josh

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  #2  
Old July 12th 05, 01:48 AM
Will Honea
external usenet poster
 
Posts: n/a
Default

On Mon, 11 Jul 2005 07:36:49 UTC JKnapp
> wrote:

> I recently purchased this vehicle and am not having the greatest of
> luck with it. for 1 I think I need to clean the CPS Connector. but as
> far as the vacuum problem down on the axle I can find where two of the
> vacuum lines goto to engage the 4x4, but there is a third line that I
> am unable to figue out where it goes. I believe it is the white line.
> the other problem that I am having is at idle it will barely have
> enough vacuum at idle to divert the air to the vent when I have the
> A/C turned on. then when I accel when I get up to about 1500 RPM I
> loose the vacuum and the Defroster is what the A/C then comes through.
> If I go back to idle It goes back to the vent sometimes. I did tape
> off the line underneth by the axle incase that was the problem but
> still acts the same. any ideas?


The 3 lines to the front axle are on, off, and vent. The vent
terminates with a filter up under the coolant bottle on the firewall -
or at least dangles in that area. The accumulator bottle for the
vacuum is located behind the bumper on the passenger side and the line
to the bottle runs under the battery - that's prone to failure and
sounds like it could be both your idle and a/c air problem. The
vacuum supply comes off the back part of the intake manifold - pull
the hose off the manifold, plug the manifold hole with your finger or
tape and see if that cures the idle. If it does, all you can do is to
start chasing hoses until you find the leak. Get the vacuum leaks
fixed before you get any further since they make everything else an
exercise in futility. Sounds like yours is probably in the main hose
off the manifold. Don't forget that the power brake vacuum also comes
off the manifold - that can really screw things up as well.

The next thing I would do woud be to do a really thorough cleaning job
on the throttle body - I finally wound up taking mine off and throwing
it into an untrasonic bath with carb cleaner (it was that bad). It
took several months of screwing around to finally get a really good
idle when I first got the thing.

--
Will Honea
  #3  
Old July 13th 05, 07:36 AM
JKnapp
external usenet poster
 
Posts: n/a
Default

"" wrote:
> On Mon, 11 Jul 2005 07:36:49 UTC JKnapp
> > wrote:
>
> > I recently purchased this vehicle and am not having the

> greatest of
> > luck with it. for 1 I think I need to clean the CPS

> Connector. but as
> > far as the vacuum problem down on the axle I can find where

> two of the
> > vacuum lines goto to engage the 4x4, but there is a third

> line that I
> > am unable to figue out where it goes. I believe it is the

> white line.
> > the other problem that I am having is at idle it will barely

> have
> > enough vacuum at idle to divert the air to the vent when I

> have the
> > A/C turned on. then when I accel when I get up to about

> 1500 RPM I
> > loose the vacuum and the Defroster is what the A/C then

> comes through.
> > If I go back to idle It goes back to the vent sometimes. I

> did tape
> > off the line underneth by the axle incase that was the

> problem but
> > still acts the same. any ideas?

>
> The 3 lines to the front axle are on, off, and vent. The vent
>
> terminates with a filter up under the coolant bottle on the
> firewall -
> or at least dangles in that area. The accumulator bottle for
> the
> vacuum is located behind the bumper on the passenger side and
> the line
> to the bottle runs under the battery - that's prone to failure
> and
> sounds like it could be both your idle and a/c air problem.
> The
> vacuum supply comes off the back part of the intake manifold -
> pull
> the hose off the manifold, plug the manifold hole with your
> finger or
> tape and see if that cures the idle. If it does, all you can
> do is to
> start chasing hoses until you find the leak. Get the vacuum
> leaks
> fixed before you get any further since they make everything
> else an
> exercise in futility. Sounds like yours is probably in the
> main hose
> off the manifold. Don't forget that the power brake vacuum
> also comes
> off the manifold - that can really screw things up as well.
>
> The next thing I would do woud be to do a really thorough
> cleaning job
> on the throttle body - I finally wound up taking mine off and
> throwing
> it into an untrasonic bath with carb cleaner (it was that
> bad). It
> took several months of screwing around to finally get a really
> good
> idle when I first got the thing.
>
> --
> Will Honea


thanks for the info I will take a look and let you know what i find.
the only thing is that in the same area you were talking about the
vent teminating i found another small vacuum line that was unhooked.
it looked to me like it hooked up to the white line coming from the
axle. the real problem with that white line is it came unhooked and
broken and i couldnt see where it is supposed to go to on the axle.

josh

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/4X4-87-Jee...ict128447.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=627842
  #4  
Old July 13th 05, 06:33 PM
Will Honea
external usenet poster
 
Posts: n/a
Default

On Wed, 13 Jul 2005 06:36:05 UTC JKnapp
> wrote:

> "" wrote:
> > On Mon, 11 Jul 2005 07:36:49 UTC JKnapp
> > > wrote:
> >
> > > I recently purchased this vehicle and am not having the

> > greatest of
> > > luck with it. for 1 I think I need to clean the CPS

> > Connector. but as
> > > far as the vacuum problem down on the axle I can find where

> > two of the
> > > vacuum lines goto to engage the 4x4, but there is a third

> > line that I
> > > am unable to figue out where it goes. I believe it is the

> > white line.
> > > the other problem that I am having is at idle it will barely

> > have
> > > enough vacuum at idle to divert the air to the vent when I

> > have the
> > > A/C turned on. then when I accel when I get up to about

> > 1500 RPM I
> > > loose the vacuum and the Defroster is what the A/C then

> > comes through.
> > > If I go back to idle It goes back to the vent sometimes. I

> > did tape
> > > off the line underneth by the axle incase that was the

> > problem but
> > > still acts the same. any ideas?

> >
> > The 3 lines to the front axle are on, off, and vent. The vent
> >
> > terminates with a filter up under the coolant bottle on the
> > firewall -
> > or at least dangles in that area. The accumulator bottle for
> > the
> > vacuum is located behind the bumper on the passenger side and
> > the line
> > to the bottle runs under the battery - that's prone to failure
> > and
> > sounds like it could be both your idle and a/c air problem.
> > The
> > vacuum supply comes off the back part of the intake manifold -
> > pull
> > the hose off the manifold, plug the manifold hole with your
> > finger or
> > tape and see if that cures the idle. If it does, all you can
> > do is to
> > start chasing hoses until you find the leak. Get the vacuum
> > leaks
> > fixed before you get any further since they make everything
> > else an
> > exercise in futility. Sounds like yours is probably in the
> > main hose
> > off the manifold. Don't forget that the power brake vacuum
> > also comes
> > off the manifold - that can really screw things up as well.
> >
> > The next thing I would do woud be to do a really thorough
> > cleaning job
> > on the throttle body - I finally wound up taking mine off and
> > throwing
> > it into an untrasonic bath with carb cleaner (it was that
> > bad). It
> > took several months of screwing around to finally get a really
> > good
> > idle when I first got the thing.
> >
> > --
> > Will Honea

>
> thanks for the info I will take a look and let you know what i find.
> the only thing is that in the same area you were talking about the
> vent teminating i found another small vacuum line that was unhooked.
> it looked to me like it hooked up to the white line coming from the
> axle. the real problem with that white line is it came unhooked and
> broken and i couldnt see where it is supposed to go to on the axle.


The axle - px side - has a "hump" with a lever coming out. That's the
vacuum shift motor. It will have 3 small plastic pipes running to a
rubber plug. Back toward the body, those lines got to another rubber
plug that connects to the rest of the system. Mine have all broken at
one time or another - I clean the hole in the plug, use a sharp knife
to get a smooth, square end on the platic tube and use Super Glue to
hold the tube in the plug.

The vent line looks like it goes nowhere up under the hood, back by
the radiator bottle on the firewall. Quick check would be to plug the
broken tube with you finger and see if idle is affected. It's a small
tube, so don't expect miracles. If plugging it affects idle, pull the
shift lever into 4WD and see if that also improves idle. I would bet
that you have a bigger vacuum leak further back in the system, tho.

--
Will Honea
  #5  
Old July 18th 05, 08:36 PM
JKnapp
external usenet poster
 
Posts: n/a
Default

"" wrote:
> On Wed, 13 Jul 2005 06:36:05 UTC JKnapp
> > wrote:
>
> > "" wrote:
> > > On Mon, 11 Jul 2005 07:36:49 UTC JKnapp
> > > > wrote:
> > >
> > > > I recently purchased this vehicle and am not having the
> > > greatest of
> > > > luck with it. for 1 I think I need to clean the CPS
> > > Connector. but as
> > > > far as the vacuum problem down on the axle I can find

> where
> > > two of the
> > > > vacuum lines goto to engage the 4x4, but there is a

> third
> > > line that I
> > > > am unable to figue out where it goes. I believe it is

> the
> > > white line.
> > > > the other problem that I am having is at idle it will

> barely
> > > have
> > > > enough vacuum at idle to divert the air to the vent

> when I
> > > have the
> > > > A/C turned on. then when I accel when I get up to

> about
> > > 1500 RPM I
> > > > loose the vacuum and the Defroster is what the A/C then
> > > comes through.
> > > > If I go back to idle It goes back to the vent

> sometimes. I
> > > did tape
> > > > off the line underneth by the axle incase that was the
> > > problem but
> > > > still acts the same. any ideas?
> > >
> > > The 3 lines to the front axle are on, off, and vent. The

> vent
> > >
> > > terminates with a filter up under the coolant bottle on

> the
> > > firewall -
> > > or at least dangles in that area. The accumulator bottle

> for
> > > the
> > > vacuum is located behind the bumper on the passenger side

> and
> > > the line
> > > to the bottle runs under the battery - that's prone to

> failure
> > > and
> > > sounds like it could be both your idle and a/c air

> problem.
> > > The
> > > vacuum supply comes off the back part of the intake

> manifold -
> > > pull
> > > the hose off the manifold, plug the manifold hole with

> your
> > > finger or
> > > tape and see if that cures the idle. If it does, all you

> can
> > > do is to
> > > start chasing hoses until you find the leak. Get the

> vacuum
> > > leaks
> > > fixed before you get any further since they make

> everything
> > > else an
> > > exercise in futility. Sounds like yours is probably in

> the
> > > main hose
> > > off the manifold. Don't forget that the power brake

> vacuum
> > > also comes
> > > off the manifold - that can really screw things up as

> well.
> > >
> > > The next thing I would do woud be to do a really thorough
> > > cleaning job
> > > on the throttle body - I finally wound up taking mine off

> and
> > > throwing
> > > it into an untrasonic bath with carb cleaner (it was that
> > > bad). It
> > > took several months of screwing around to finally get a

> really
> > > good
> > > idle when I first got the thing.
> > >
> > > --
> > > Will Honea

> >
> > thanks for the info I will take a look and let you know what

> i find.
> > the only thing is that in the same area you were talking

> about the
> > vent teminating i found another small vacuum line that was

> unhooked.
> > it looked to me like it hooked up to the white line coming

> from the
> > axle. the real problem with that white line is it came

> unhooked and
> > broken and i couldnt see where it is supposed to go to on

> the axle.
>
> The axle - px side - has a "hump" with a lever coming out.
> That's the
> vacuum shift motor. It will have 3 small plastic pipes
> running to a
> rubber plug. Back toward the body, those lines got to
> another rubber
> plug that connects to the rest of the system. Mine have all
> broken at
> one time or another - I clean the hole in the plug, use a
> sharp knife
> to get a smooth, square end on the platic tube and use Super
> Glue to
> hold the tube in the plug.
>
> The vent line looks like it goes nowhere up under the hood,
> back by
> the radiator bottle on the firewall. Quick check would be to
> plug the
> broken tube with you finger and see if idle is affected. It's
> a small
> tube, so don't expect miracles. If plugging it affects idle,
> pull the
> shift lever into 4WD and see if that also improves idle. I
> would bet
> that you have a bigger vacuum leak further back in the system,
> tho.
>
> --
> Will Honea


I posted a picture on my website showing my next question. here is a
link
http://jknapp.home.mchsi.com/question.html
I have figured out what happened on my axle they replaced a hose and
was messing with me.any how I cannot find whatr this blue hose is for
I taped of the open end so it should not leak but I still dont know
where it is going to or from. any ideas? do i need to remove the tape?

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/4X4-87-Jee...ict128447.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=628637
  #6  
Old July 18th 05, 11:17 PM
Will Honea
external usenet poster
 
Posts: n/a
Default

On Mon, 18 Jul 2005 19:36:29 UTC JKnapp
> wrote:
> I posted a picture on my website showing my next question. here is a
> link
> http://jknapp.home.mchsi.com/question.html
> I have figured out what happened on my axle they replaced a hose and
> was messing with me.any how I cannot find whatr this blue hose is for
> I taped of the open end so it should not leak but I still dont know
> where it is going to or from. any ideas? do i need to remove the tape?


Thaty looks like the vent hose. Mine has a plactic gozmo on the end -
sort of a filter screen, looks like. That does just what your's is
doing and just site there. It serves as the vent for the vacuum motor
down on the axle. Just tie it up high so it won't suck water.

--
Will Honea
 




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