Rough Idle on 1990 Jeep Wrangler

I've had my 1990 Jeep Wrangler for about 5 years. For a while now
though it has had trouble keeping a steady idle. Labor Day weekend, I
had to get a new engine for it, and I thought the mechanic could tune
the carb so it finally idles correctly. He told me though that he
doesn't understand the electric feedback carburetor systemt and to try
someone else. So here is what it does.

It won't idle at all now, and the idle screw is turned almost all the
way in, When it did idle it keeps sputtering after i turn it off. It
idles fine while choked when it is cold, but when the choke goes off
and it warms up, it can't keep running. I was reading on others and
they mentioned egr valve, but then again I don't know to much about the
egr valve. When the jeep runs the egr pulsates in and out and doesn't
just open and stay open or close and stay close, is this how it is
supposed to work or is it supposed to open and close as necessary.
Hopefully one of you Jeep lovers out there can help me out.

Jacob

www.off-road.com/jeep/tech/engine/carter.html


"Jacob_T" > wrote in message
oups.com...
> I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> though it has had trouble keeping a steady idle. Labor Day weekend, I
> had to get a new engine for it, and I thought the mechanic could tune
> the carb so it finally idles correctly. He told me though that he
> doesn't understand the electric feedback carburetor systemt and to try
> someone else. So here is what it does.
>
> It won't idle at all now, and the idle screw is turned almost all the
> way in, When it did idle it keeps sputtering after i turn it off. It
> idles fine while choked when it is cold, but when the choke goes off
> and it warms up, it can't keep running. I was reading on others and
> they mentioned egr valve, but then again I don't know to much about the
> egr valve. When the jeep runs the egr pulsates in and out and doesn't
> just open and stay open or close and stay close, is this how it is
> supposed to work or is it supposed to open and close as necessary.
> Hopefully one of you Jeep lovers out there can help me out.
>
> Jacob
>

One common failure is the charcoal canister. When it fails totally, the
idle will surge which will make the EGR go in and out or just not want
to work and a pile of oil gets puked into the air filter imitating a
blown engine...

To test this, you follow the PCV line from the front of the valve cover
to the back of the carb. At the back you will find a t fitting or a
solenoid thing with another line coming off it. This other line goes
way down behind the fender to the top of the charcoal canister. At idle
pinch this line closed. If the idle changes, the canister purge valve
is dead.

You can take this line off the canister and plug it at the carb
'temporarily' to set the carb up right. You will need this canister
plugged back in to avoid a lot of gas fumes because the canister is the
vent for the gas tank and float bowls.

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)

Jacob_T wrote:
>
> I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> though it has had trouble keeping a steady idle. Labor Day weekend, I
> had to get a new engine for it, and I thought the mechanic could tune
> the carb so it finally idles correctly. He told me though that he
> doesn't understand the electric feedback carburetor systemt and to try
> someone else. So here is what it does.
>
> It won't idle at all now, and the idle screw is turned almost all the
> way in, When it did idle it keeps sputtering after i turn it off. It
> idles fine while choked when it is cold, but when the choke goes off
> and it warms up, it can't keep running. I was reading on others and
> they mentioned egr valve, but then again I don't know to much about the
> egr valve. When the jeep runs the egr pulsates in and out and doesn't
> just open and stay open or close and stay close, is this how it is
> supposed to work or is it supposed to open and close as necessary.
> Hopefully one of you Jeep lovers out there can help me out.
>
> Jacob

Checking the idle tubes turned out to be fruitful as they were nearly
completely clogged. Thank you for you recomendation.


Steve Foley wrote:
> www.off-road.com/jeep/tech/engine/carter.html
>
>
> "Jacob_T" > wrote in message
> oups.com...
> > I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> > though it has had trouble keeping a steady idle. Labor Day weekend, I
> > had to get a new engine for it, and I thought the mechanic could tune
> > the carb so it finally idles correctly. He told me though that he
> > doesn't understand the electric feedback carburetor systemt and to try
> > someone else. So here is what it does.
> >
> > It won't idle at all now, and the idle screw is turned almost all the
> > way in, When it did idle it keeps sputtering after i turn it off. It
> > idles fine while choked when it is cold, but when the choke goes off
> > and it warms up, it can't keep running. I was reading on others and
> > they mentioned egr valve, but then again I don't know to much about the
> > egr valve. When the jeep runs the egr pulsates in and out and doesn't
> > just open and stay open or close and stay close, is this how it is
> > supposed to work or is it supposed to open and close as necessary.
> > Hopefully one of you Jeep lovers out there can help me out.
> >
> > Jacob
> >

Thank you for your help in getting my jeep up and running again. It
was greatly appreciated.

Mike Romain wrote:
> One common failure is the charcoal canister. When it fails totally, the
> idle will surge which will make the EGR go in and out or just not want
> to work and a pile of oil gets puked into the air filter imitating a
> blown engine...
>
> To test this, you follow the PCV line from the front of the valve cover
> to the back of the carb. At the back you will find a t fitting or a
> solenoid thing with another line coming off it. This other line goes
> way down behind the fender to the top of the charcoal canister. At idle
> pinch this line closed. If the idle changes, the canister purge valve
> is dead.
>
> You can take this line off the canister and plug it at the carb
> 'temporarily' to set the carb up right. You will need this canister
> plugged back in to avoid a lot of gas fumes because the canister is the
> vent for the gas tank and float bowls.
>
> 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)
>
> Jacob_T wrote:
> >
> > I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> > though it has had trouble keeping a steady idle. Labor Day weekend, I
> > had to get a new engine for it, and I thought the mechanic could tune
> > the carb so it finally idles correctly. He told me though that he
> > doesn't understand the electric feedback carburetor systemt and to try
> > someone else. So here is what it does.
> >
> > It won't idle at all now, and the idle screw is turned almost all the
> > way in, When it did idle it keeps sputtering after i turn it off. It
> > idles fine while choked when it is cold, but when the choke goes off
> > and it warms up, it can't keep running. I was reading on others and
> > they mentioned egr valve, but then again I don't know to much about the
> > egr valve. When the jeep runs the egr pulsates in and out and doesn't
> > just open and stay open or close and stay close, is this how it is
> > supposed to work or is it supposed to open and close as necessary.
> > Hopefully one of you Jeep lovers out there can help me out.
> >
> > Jacob

Change your fuel filter, attached to the front right frame rail.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

Jacob_T wrote:
>
> Checking the idle tubes turned out to be fruitful as they were nearly
> completely clogged. Thank you for you recomendation.

left

> Change your fuel filter, attached to the front right frame rail.
> God Bless America, Bill O|||||||O
> http://www.billhughes.com/
>
> Jacob_T wrote:
> >
> > Checking the idle tubes turned out to be fruitful as they were nearly
> > completely clogged. Thank you for you recomendation.

Just a FYI for you. The tube that runs from the gas filter and loops
down to the carb has a tendency to get junk in it from gas evaporating
when it sits. This junk is after the filter and can easily get back
into the idle tubes.

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)

Jacob_T wrote:
>
> Checking the idle tubes turned out to be fruitful as they were nearly
> completely clogged. Thank you for you recomendation.
>
> Steve Foley wrote:
> > www.off-road.com/jeep/tech/engine/carter.html
> >
> >
> > "Jacob_T" > wrote in message
> > oups.com...
> > > I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> > > though it has had trouble keeping a steady idle. Labor Day weekend, I
> > > had to get a new engine for it, and I thought the mechanic could tune
> > > the carb so it finally idles correctly. He told me though that he
> > > doesn't understand the electric feedback carburetor systemt and to try
> > > someone else. So here is what it does.
> > >
> > > It won't idle at all now, and the idle screw is turned almost all the
> > > way in, When it did idle it keeps sputtering after i turn it off. It
> > > idles fine while choked when it is cold, but when the choke goes off
> > > and it warms up, it can't keep running. I was reading on others and
> > > they mentioned egr valve, but then again I don't know to much about the
> > > egr valve. When the jeep runs the egr pulsates in and out and doesn't
> > > just open and stay open or close and stay close, is this how it is
> > > supposed to work or is it supposed to open and close as necessary.
> > > Hopefully one of you Jeep lovers out there can help me out.
> > >
> > > Jacob
> > >

How do you clean that... GumOut?


"Mike Romain" > wrote in message
...
> Just a FYI for you. The tube that runs from the gas filter and loops
> down to the carb has a tendency to get junk in it from gas evaporating
> when it sits. This junk is after the filter and can easily get back
> into the idle tubes.
>
> 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)
>
> Jacob_T wrote:
>>
>> Checking the idle tubes turned out to be fruitful as they were nearly
>> completely clogged. Thank you for you recomendation.
>>
>> Steve Foley wrote:
>> > www.off-road.com/jeep/tech/engine/carter.html
>> >
>> >
>> > "Jacob_T" > wrote in message
>> > oups.com...
>> > > I've had my 1990 Jeep Wrangler for about 5 years. For a while now
>> > > though it has had trouble keeping a steady idle. Labor Day weekend,
>> > > I
>> > > had to get a new engine for it, and I thought the mechanic could tune
>> > > the carb so it finally idles correctly. He told me though that he
>> > > doesn't understand the electric feedback carburetor systemt and to
>> > > try
>> > > someone else. So here is what it does.
>> > >
>> > > It won't idle at all now, and the idle screw is turned almost all the
>> > > way in, When it did idle it keeps sputtering after i turn it off.
>> > > It
>> > > idles fine while choked when it is cold, but when the choke goes off
>> > > and it warms up, it can't keep running. I was reading on others and
>> > > they mentioned egr valve, but then again I don't know to much about
>> > > the
>> > > egr valve. When the jeep runs the egr pulsates in and out and
>> > > doesn't
>> > > just open and stay open or close and stay close, is this how it is
>> > > supposed to work or is it supposed to open and close as necessary.
>> > > Hopefully one of you Jeep lovers out there can help me out.
>> > >
>> > > Jacob
>> > >

I use spray carb cleaner.

Mike

billy ray wrote:
>
> How do you clean that... GumOut?
>
> "Mike Romain" > wrote in message
> ...
> > Just a FYI for you. The tube that runs from the gas filter and loops
> > down to the carb has a tendency to get junk in it from gas evaporating
> > when it sits. This junk is after the filter and can easily get back
> > into the idle tubes.
> >
> > 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)
> >
> > Jacob_T wrote:
> >>
> >> Checking the idle tubes turned out to be fruitful as they were nearly
> >> completely clogged. Thank you for you recomendation.
> >>
> >> Steve Foley wrote:
> >> > www.off-road.com/jeep/tech/engine/carter.html
> >> >
> >> >
> >> > "Jacob_T" > wrote in message
> >> > oups.com...
> >> > > I've had my 1990 Jeep Wrangler for about 5 years. For a while now
> >> > > though it has had trouble keeping a steady idle. Labor Day weekend,
> >> > > I
> >> > > had to get a new engine for it, and I thought the mechanic could tune
> >> > > the carb so it finally idles correctly. He told me though that he
> >> > > doesn't understand the electric feedback carburetor systemt and to
> >> > > try
> >> > > someone else. So here is what it does.
> >> > >
> >> > > It won't idle at all now, and the idle screw is turned almost all the
> >> > > way in, When it did idle it keeps sputtering after i turn it off.
> >> > > It
> >> > > idles fine while choked when it is cold, but when the choke goes off
> >> > > and it warms up, it can't keep running. I was reading on others and
> >> > > they mentioned egr valve, but then again I don't know to much about
> >> > > the
> >> > > egr valve. When the jeep runs the egr pulsates in and out and
> >> > > doesn't
> >> > > just open and stay open or close and stay close, is this how it is
> >> > > supposed to work or is it supposed to open and close as necessary.
> >> > > Hopefully one of you Jeep lovers out there can help me out.
> >> > >
> >> > > Jacob
> >> > >