Re: CJ - backfiring problem help (a little long)
 

Mike is not all that old......


"Earle Horton" <earle-NOSPAM-horton@msn.com> wrote in message
news:448ec07e$0$3554$88260bb3@free.teranews.com...
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture.
> With
> older models you simply back off the idle mixture screw, until the engine
> is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
>> My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
>> 4.11's, Detroits, etc and "full" factory emissions crap meaning
>> computer, pulse air and all those vacuum lines etc (I have one more WA
>> state emissions test to pass before it "ages out" and it no longer
>> needs to be tested) is having a mild to severe "backfiring problem"
>> on deceleration. LOTS of popping and noises out the exhaust when I
>> decelerate or downshift.
>>
>> The timing is set at "about 12 degrees" before TDC (which
>> Chilton's suggests is about right - (pretty sure it's a California
>> model). The timing mark sorta "bounces around" when I check it
>> witht the light (distributor vacuum line disconnected and plugged) -
>> possibly due to some wear in the distributor or ??. I have another
>> distributor to swap in to "test" the wear theory, but haven't had
>> the time to do so yet.
>>
>> Anyway - if I advance the timing further which significantly improves
>> the driveability and idle, I start to get engine pinging (a little
>> difficult to hear over the tires) - so I don't really want to leave
>> it too far advanced. I'm running 87 octane - NOT from Arco.
>>
>> But I'd like to improve the drive-ability, STOP the "backfiring",
>> and not damage the engine.
>>
>> Any thoughts or guidance?
>>
>> Thanks
>>
>> Lynn in Vancouver, WA
>>
>
>
>
> --
> Posted via a free Usenet account from http://www.teranews.com
>

Re: CJ - backfiring problem help (a little long)
 

Mike is not all that old......


"Earle Horton" <earle-NOSPAM-horton@msn.com> wrote in message
news:448ec07e$0$3554$88260bb3@free.teranews.com...
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture.
> With
> older models you simply back off the idle mixture screw, until the engine
> is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
>> My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
>> 4.11's, Detroits, etc and "full" factory emissions crap meaning
>> computer, pulse air and all those vacuum lines etc (I have one more WA
>> state emissions test to pass before it "ages out" and it no longer
>> needs to be tested) is having a mild to severe "backfiring problem"
>> on deceleration. LOTS of popping and noises out the exhaust when I
>> decelerate or downshift.
>>
>> The timing is set at "about 12 degrees" before TDC (which
>> Chilton's suggests is about right - (pretty sure it's a California
>> model). The timing mark sorta "bounces around" when I check it
>> witht the light (distributor vacuum line disconnected and plugged) -
>> possibly due to some wear in the distributor or ??. I have another
>> distributor to swap in to "test" the wear theory, but haven't had
>> the time to do so yet.
>>
>> Anyway - if I advance the timing further which significantly improves
>> the driveability and idle, I start to get engine pinging (a little
>> difficult to hear over the tires) - so I don't really want to leave
>> it too far advanced. I'm running 87 octane - NOT from Arco.
>>
>> But I'd like to improve the drive-ability, STOP the "backfiring",
>> and not damage the engine.
>>
>> Any thoughts or guidance?
>>
>> Thanks
>>
>> Lynn in Vancouver, WA
>>
>
>
>
> --
> Posted via a free Usenet account from http://www.teranews.com
>

Re: CJ - backfiring problem help (a little long)
 

Mike is not all that old......


"Earle Horton" <earle-NOSPAM-horton@msn.com> wrote in message
news:448ec07e$0$3554$88260bb3@free.teranews.com...
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture.
> With
> older models you simply back off the idle mixture screw, until the engine
> is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
>> My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
>> 4.11's, Detroits, etc and "full" factory emissions crap meaning
>> computer, pulse air and all those vacuum lines etc (I have one more WA
>> state emissions test to pass before it "ages out" and it no longer
>> needs to be tested) is having a mild to severe "backfiring problem"
>> on deceleration. LOTS of popping and noises out the exhaust when I
>> decelerate or downshift.
>>
>> The timing is set at "about 12 degrees" before TDC (which
>> Chilton's suggests is about right - (pretty sure it's a California
>> model). The timing mark sorta "bounces around" when I check it
>> witht the light (distributor vacuum line disconnected and plugged) -
>> possibly due to some wear in the distributor or ??. I have another
>> distributor to swap in to "test" the wear theory, but haven't had
>> the time to do so yet.
>>
>> Anyway - if I advance the timing further which significantly improves
>> the driveability and idle, I start to get engine pinging (a little
>> difficult to hear over the tires) - so I don't really want to leave
>> it too far advanced. I'm running 87 octane - NOT from Arco.
>>
>> But I'd like to improve the drive-ability, STOP the "backfiring",
>> and not damage the engine.
>>
>> Any thoughts or guidance?
>>
>> Thanks
>>
>> Lynn in Vancouver, WA
>>
>
>
>
> --
> Posted via a free Usenet account from http://www.teranews.com
>

Re: CJ - backfiring problem help (a little long)
 

Hey there old timer, who you callin' old?

One sign of a vacuum leak is oil puking into the air filter. If that is
also happening along with a crappy idle, the OP should post back.

The carb 'can' be adjusted for mix, but it is supposed to stay factory
set so the computer does the mix. It 'can' be set back factory if
needed. That is another fix.

If the engine won't idle under 1100 or so rpm, then there is another fix
for that. (plugged 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)

Earle Horton wrote:
>
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture. With
> older models you simply back off the idle mixture screw, until the engine is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
> > My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
> > 4.11's, Detroits, etc and "full" factory emissions crap meaning
> > computer, pulse air and all those vacuum lines etc (I have one more WA
> > state emissions test to pass before it "ages out" and it no longer
> > needs to be tested) is having a mild to severe "backfiring problem"
> > on deceleration. LOTS of popping and noises out the exhaust when I
> > decelerate or downshift.
> >
> > The timing is set at "about 12 degrees" before TDC (which
> > Chilton's suggests is about right - (pretty sure it's a California
> > model). The timing mark sorta "bounces around" when I check it
> > witht the light (distributor vacuum line disconnected and plugged) -
> > possibly due to some wear in the distributor or ??. I have another
> > distributor to swap in to "test" the wear theory, but haven't had
> > the time to do so yet.
> >
> > Anyway - if I advance the timing further which significantly improves
> > the driveability and idle, I start to get engine pinging (a little
> > difficult to hear over the tires) - so I don't really want to leave
> > it too far advanced. I'm running 87 octane - NOT from Arco.
> >
> > But I'd like to improve the drive-ability, STOP the "backfiring",
> > and not damage the engine.
> >
> > Any thoughts or guidance?
> >
> > Thanks
> >
> > Lynn in Vancouver, WA
> >
>
> --
> Posted via a free Usenet account from http://www.teranews.com

Re: CJ - backfiring problem help (a little long)
 

Hey there old timer, who you callin' old?

One sign of a vacuum leak is oil puking into the air filter. If that is
also happening along with a crappy idle, the OP should post back.

The carb 'can' be adjusted for mix, but it is supposed to stay factory
set so the computer does the mix. It 'can' be set back factory if
needed. That is another fix.

If the engine won't idle under 1100 or so rpm, then there is another fix
for that. (plugged 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)

Earle Horton wrote:
>
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture. With
> older models you simply back off the idle mixture screw, until the engine is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
> > My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
> > 4.11's, Detroits, etc and "full" factory emissions crap meaning
> > computer, pulse air and all those vacuum lines etc (I have one more WA
> > state emissions test to pass before it "ages out" and it no longer
> > needs to be tested) is having a mild to severe "backfiring problem"
> > on deceleration. LOTS of popping and noises out the exhaust when I
> > decelerate or downshift.
> >
> > The timing is set at "about 12 degrees" before TDC (which
> > Chilton's suggests is about right - (pretty sure it's a California
> > model). The timing mark sorta "bounces around" when I check it
> > witht the light (distributor vacuum line disconnected and plugged) -
> > possibly due to some wear in the distributor or ??. I have another
> > distributor to swap in to "test" the wear theory, but haven't had
> > the time to do so yet.
> >
> > Anyway - if I advance the timing further which significantly improves
> > the driveability and idle, I start to get engine pinging (a little
> > difficult to hear over the tires) - so I don't really want to leave
> > it too far advanced. I'm running 87 octane - NOT from Arco.
> >
> > But I'd like to improve the drive-ability, STOP the "backfiring",
> > and not damage the engine.
> >
> > Any thoughts or guidance?
> >
> > Thanks
> >
> > Lynn in Vancouver, WA
> >
>
> --
> Posted via a free Usenet account from http://www.teranews.com

Re: CJ - backfiring problem help (a little long)
 

Hey there old timer, who you callin' old?

One sign of a vacuum leak is oil puking into the air filter. If that is
also happening along with a crappy idle, the OP should post back.

The carb 'can' be adjusted for mix, but it is supposed to stay factory
set so the computer does the mix. It 'can' be set back factory if
needed. That is another fix.

If the engine won't idle under 1100 or so rpm, then there is another fix
for that. (plugged 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)

Earle Horton wrote:
>
> The most common cause for backfiring on deceleration is idle mixture too
> lean. That could be a vacuum leak with this vintage. They really do have
> too many vacuum lines, don't they? If that is not it, then short of a new
> or rebuilt carburetor, I don't know how you get a proper idle mixture. With
> older models you simply back off the idle mixture screw, until the engine is
> getting a rich enough mixture. With the smog controlled models, there is
> usually something to prevent that.
>
> Mike and Bill have some good ideas too. Just don't take either of those
> guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
> Earle
>
> <lynnhowlyn@aol.com> wrote in message
> news:1150170260.713493.323610@y43g2000cwc.googlegr oups.com...
> > My 83 CJ7 with a stock (so far as I know) 258, T176, D300, 33's,
> > 4.11's, Detroits, etc and "full" factory emissions crap meaning
> > computer, pulse air and all those vacuum lines etc (I have one more WA
> > state emissions test to pass before it "ages out" and it no longer
> > needs to be tested) is having a mild to severe "backfiring problem"
> > on deceleration. LOTS of popping and noises out the exhaust when I
> > decelerate or downshift.
> >
> > The timing is set at "about 12 degrees" before TDC (which
> > Chilton's suggests is about right - (pretty sure it's a California
> > model). The timing mark sorta "bounces around" when I check it
> > witht the light (distributor vacuum line disconnected and plugged) -
> > possibly due to some wear in the distributor or ??. I have another
> > distributor to swap in to "test" the wear theory, but haven't had
> > the time to do so yet.
> >
> > Anyway - if I advance the timing further which significantly improves
> > the driveability and idle, I start to get engine pinging (a little
> > difficult to hear over the tires) - so I don't really want to leave
> > it too far advanced. I'm running 87 octane - NOT from Arco.
> >
> > But I'd like to improve the drive-ability, STOP the "backfiring",
> > and not damage the engine.
> >
> > Any thoughts or guidance?
> >
> > Thanks
> >
> > Lynn in Vancouver, WA
> >
>
> --
> Posted via a free Usenet account from http://www.teranews.com

Re: CJ - backfiring problem help (a little long)
 

On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
<earle-NOSPAM-horton@msn.com> wrote:

>The most common cause for backfiring on deceleration is idle mixture too
>lean. That could be a vacuum leak with this vintage. They really do have
>too many vacuum lines, don't they? If that is not it, then short of a new
>or rebuilt carburetor, I don't know how you get a proper idle mixture. With
>older models you simply back off the idle mixture screw, until the engine is
>getting a rich enough mixture. With the smog controlled models, there is
>usually something to prevent that.

Plastic caps that are easily removed with a pocket/exacto knife or the
tip of a soldering iron (both are standard shop practices).

Dan
>
>Mike and Bill have some good ideas too. Just don't take either of those
>guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
>Earle

Re: CJ - backfiring problem help (a little long)
 

On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
<earle-NOSPAM-horton@msn.com> wrote:

>The most common cause for backfiring on deceleration is idle mixture too
>lean. That could be a vacuum leak with this vintage. They really do have
>too many vacuum lines, don't they? If that is not it, then short of a new
>or rebuilt carburetor, I don't know how you get a proper idle mixture. With
>older models you simply back off the idle mixture screw, until the engine is
>getting a rich enough mixture. With the smog controlled models, there is
>usually something to prevent that.

Plastic caps that are easily removed with a pocket/exacto knife or the
tip of a soldering iron (both are standard shop practices).

Dan
>
>Mike and Bill have some good ideas too. Just don't take either of those
>guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
>Earle

Re: CJ - backfiring problem help (a little long)
 

On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
<earle-NOSPAM-horton@msn.com> wrote:

>The most common cause for backfiring on deceleration is idle mixture too
>lean. That could be a vacuum leak with this vintage. They really do have
>too many vacuum lines, don't they? If that is not it, then short of a new
>or rebuilt carburetor, I don't know how you get a proper idle mixture. With
>older models you simply back off the idle mixture screw, until the engine is
>getting a rich enough mixture. With the smog controlled models, there is
>usually something to prevent that.

Plastic caps that are easily removed with a pocket/exacto knife or the
tip of a soldering iron (both are standard shop practices).

Dan
>
>Mike and Bill have some good ideas too. Just don't take either of those
>guys too seriously. They are pretty old and grizzled, both of them. ;^)
>
>Earle

Re: CJ - backfiring problem help (a little long)
 

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> <earle-NOSPAM-horton@msn.com> wrote:
>
> >The most common cause for backfiring on deceleration is idle mixture too
> >lean. That could be a vacuum leak with this vintage. They really do
> >have too many vacuum lines, don't they? If that is not it, then short
> >of a new or rebuilt carburetor, I don't know how you get a proper
> >idle mixture. With older models you simply back off the idle mixture
> >screw, until the engine is getting a rich enough mixture. With the smog
> >controlled models, there is
> >usually something to prevent that.
>
> Plastic caps that are easily removed with a pocket/exacto knife or the
> tip of a soldering iron (both are standard shop practices).
>
Quite. If you are going to do that, it is a good idea to record the number
of turns out for the factory setting. Just in case you later decide, that
the problem was something else.

Earle