258 wierd idle
02-21-2004, 07:20 PM
#11
Guest
Posts: n/a
Re: 258 wierd idle
OK this is just strange. Since the original bbd carb was giving me so much
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
02-21-2004, 07:20 PM
#12
Guest
Posts: n/a
Re: 258 wierd idle
OK this is just strange. Since the original bbd carb was giving me so much
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
02-21-2004, 07:20 PM
#13
Guest
Posts: n/a
Re: 258 wierd idle
OK this is just strange. Since the original bbd carb was giving me so much
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
trouble lately, I bought a new one today. Rebuilt Autozone special -- I
know, I know. The choke doesn't work out of the box so it's going back
tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
(still dialing it in), the same symptoms exist where I can pull any of the
plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
it STILL exhibits the same behavior. The cap/rotor are nearly new and in
good condition. I know I'm getting good spark on 4-6 - plenty of arc when
shorted to the block. Compression is even at 155-160 across all cylinders.
WTF is going on here?
> From: Mike Romain <romainm@sympatico.ca>
> Organization: Bell Sympatico
> Newsgroups: rec.autos.makers.jeep+******
> Date: Sat, 14 Feb 2004 12:30:30 -0500
> Subject: Re: 258 wierd idle
>
> I have seen exactly that, recently too.
>
> One of the barrels of the carb is not giving gas at idle.
>
> If the idle tube is clean, then maybe the venturi is clogged up.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> KurtS wrote:
>>
>> 85 CJ7/258/computer is asleep
>>
>> A few weeks ago my idle started running rough and the exhaust sounded like
>> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
>> the exhaust pressure was higher. The weather is finally warm enough to work
>> on this today. I pulled all the plugs to check their condition. 1-4 were
>> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
>> all back together and got no improvement. I started pulling spark wires one
>> by one until the engine ran worse. Much to my surprise, I could pull off
>> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
>> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
>> - decided to give 'em another half turn out just to see if it made a
>> difference. The idle is a little better but I still get no change in idle if
>> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
>> wires, cap and rotor have about 600 miles on them and all contacts are
>> clean. Any thoughts?
02-22-2004, 09:54 AM
#14
Guest
Posts: n/a
Re: 258 wierd idle
Leaky intake gasket?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
02-22-2004, 09:54 AM
#15
Guest
Posts: n/a
Re: 258 wierd idle
Leaky intake gasket?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
02-22-2004, 09:54 AM
#16
Guest
Posts: n/a
Re: 258 wierd idle
Leaky intake gasket?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
Maybe try some carb cleaner spray along the intake gasket to head crack
and listen for any idle changes.
Oh and a heads up on that 'new' carb. I have seen 3 'new' carbs that
came with pre-plugged up idle tubes and ran as bad if not worse than the
ones being replaced.
When the rebuilders get them, they only use chemicals on the clean up.
The idle tubes need a physical ream which is a big no no for any
rebuilder to do.
Mike
KurtS wrote:
>
> OK this is just strange. Since the original bbd carb was giving me so much
> trouble lately, I bought a new one today. Rebuilt Autozone special -- I
> know, I know. The choke doesn't work out of the box so it's going back
> tomorrow. Sigh. Anyway, put the new carb in and while the idle is better
> (still dialing it in), the same symptoms exist where I can pull any of the
> plug wires on cyl's 4-6 and the idle doesn't change. Pull any of 1-3 and it
> stumbles like I would expect. I swapped in known good wires/plugs on 4-6 and
> it STILL exhibits the same behavior. The cap/rotor are nearly new and in
> good condition. I know I'm getting good spark on 4-6 - plenty of arc when
> shorted to the block. Compression is even at 155-160 across all cylinders.
> WTF is going on here?
>
> > From: Mike Romain <romainm@sympatico.ca>
> > Organization: Bell Sympatico
> > Newsgroups: rec.autos.makers.jeep+******
> > Date: Sat, 14 Feb 2004 12:30:30 -0500
> > Subject: Re: 258 wierd idle
> >
> > I have seen exactly that, recently too.
> >
> > One of the barrels of the carb is not giving gas at idle.
> >
> > If the idle tube is clean, then maybe the venturi is clogged up.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > KurtS wrote:
> >>
> >> 85 CJ7/258/computer is asleep
> >>
> >> A few weeks ago my idle started running rough and the exhaust sounded like
> >> at least one cylinder wasn't firing - a rhythmic putt putt putt sound and
> >> the exhaust pressure was higher. The weather is finally warm enough to work
> >> on this today. I pulled all the plugs to check their condition. 1-4 were
> >> nice and tan, 5&6 were a little oily. I reamed the idle tubes well. Stuck it
> >> all back together and got no improvement. I started pulling spark wires one
> >> by one until the engine ran worse. Much to my surprise, I could pull off
> >> #4-6 with no change in idle. with 1-3 off, the engine ran rougher as
> >> expected. I rechecked the idle mix screws and the were both at 3.5 turns out
> >> - decided to give 'em another half turn out just to see if it made a
> >> difference. The idle is a little better but I still get no change in idle if
> >> i pull plug wires 4-6. Any ideas? Am I really running on 3 cylinders? The
> >> wires, cap and rotor have about 600 miles on them and all contacts are
> >> clean. Any thoughts?
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Ron Croonenberg
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