Timing advancing too much... solution?
09-01-2003, 10:28 AM
#1
Guest
Posts: n/a
Timing advancing too much... solution?
89 YJ I6, bored .30 over, RV cam, Weber 38DGES
Since I put the Weber on my 89 I've had this problem - set the initial
timing just right, and when the vacuum advance is re-connected , it will
advance too much at low speed under 4lo load causing piston-killing
detonation. I've tried retarding the initial timing and that takes care of
it to an extent, but then the idle is crap. Is there a way to retard the
vacuum advance? I think the entire problem is the monstrous vacuum coming
off the Weber. Any help/advice would be greatly appreciated.
--------------------
89 YJ 6 Low input, High output
95 YJ 4 High input, Low output
03 Rubicon - High Payment
Since I put the Weber on my 89 I've had this problem - set the initial
timing just right, and when the vacuum advance is re-connected , it will
advance too much at low speed under 4lo load causing piston-killing
detonation. I've tried retarding the initial timing and that takes care of
it to an extent, but then the idle is crap. Is there a way to retard the
vacuum advance? I think the entire problem is the monstrous vacuum coming
off the Weber. Any help/advice would be greatly appreciated.
--------------------
89 YJ 6 Low input, High output
95 YJ 4 High input, Low output
03 Rubicon - High Payment
09-01-2003, 11:25 AM
#2
Guest
Posts: n/a
Re: Timing advancing too much... solution?
I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
distributor. You need to get a bigger idle jet from Weber. Your problem is
that you have to open your throttle plate too much to get the idle you need,
this exposes the "ported vacuum" for your advance. If you get a bigger jet
you can close your throttle and only get vacuum when you hit the gas. The
way to get around it is to set your timing with the advance connected, you
will have a flat spot when accelerating but your idle and low end will be
there. I had to go from a .70 to a .80 jet because of my headers.
Scott
90YJ
"Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
>
> Since I put the Weber on my 89 I've had this problem - set the initial
> timing just right, and when the vacuum advance is re-connected , it will
> advance too much at low speed under 4lo load causing piston-killing
> detonation. I've tried retarding the initial timing and that takes care of
> it to an extent, but then the idle is crap. Is there a way to retard the
> vacuum advance? I think the entire problem is the monstrous vacuum coming
> off the Weber. Any help/advice would be greatly appreciated.
>
> --------------------
> 89 YJ 6 Low input, High output
> 95 YJ 4 High input, Low output
> 03 Rubicon - High Payment
>
>
distributor. You need to get a bigger idle jet from Weber. Your problem is
that you have to open your throttle plate too much to get the idle you need,
this exposes the "ported vacuum" for your advance. If you get a bigger jet
you can close your throttle and only get vacuum when you hit the gas. The
way to get around it is to set your timing with the advance connected, you
will have a flat spot when accelerating but your idle and low end will be
there. I had to go from a .70 to a .80 jet because of my headers.
Scott
90YJ
"Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
>
> Since I put the Weber on my 89 I've had this problem - set the initial
> timing just right, and when the vacuum advance is re-connected , it will
> advance too much at low speed under 4lo load causing piston-killing
> detonation. I've tried retarding the initial timing and that takes care of
> it to an extent, but then the idle is crap. Is there a way to retard the
> vacuum advance? I think the entire problem is the monstrous vacuum coming
> off the Weber. Any help/advice would be greatly appreciated.
>
> --------------------
> 89 YJ 6 Low input, High output
> 95 YJ 4 High input, Low output
> 03 Rubicon - High Payment
>
>
09-01-2003, 11:25 AM
#3
Guest
Posts: n/a
Re: Timing advancing too much... solution?
I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
distributor. You need to get a bigger idle jet from Weber. Your problem is
that you have to open your throttle plate too much to get the idle you need,
this exposes the "ported vacuum" for your advance. If you get a bigger jet
you can close your throttle and only get vacuum when you hit the gas. The
way to get around it is to set your timing with the advance connected, you
will have a flat spot when accelerating but your idle and low end will be
there. I had to go from a .70 to a .80 jet because of my headers.
Scott
90YJ
"Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
>
> Since I put the Weber on my 89 I've had this problem - set the initial
> timing just right, and when the vacuum advance is re-connected , it will
> advance too much at low speed under 4lo load causing piston-killing
> detonation. I've tried retarding the initial timing and that takes care of
> it to an extent, but then the idle is crap. Is there a way to retard the
> vacuum advance? I think the entire problem is the monstrous vacuum coming
> off the Weber. Any help/advice would be greatly appreciated.
>
> --------------------
> 89 YJ 6 Low input, High output
> 95 YJ 4 High input, Low output
> 03 Rubicon - High Payment
>
>
distributor. You need to get a bigger idle jet from Weber. Your problem is
that you have to open your throttle plate too much to get the idle you need,
this exposes the "ported vacuum" for your advance. If you get a bigger jet
you can close your throttle and only get vacuum when you hit the gas. The
way to get around it is to set your timing with the advance connected, you
will have a flat spot when accelerating but your idle and low end will be
there. I had to go from a .70 to a .80 jet because of my headers.
Scott
90YJ
"Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
>
> Since I put the Weber on my 89 I've had this problem - set the initial
> timing just right, and when the vacuum advance is re-connected , it will
> advance too much at low speed under 4lo load causing piston-killing
> detonation. I've tried retarding the initial timing and that takes care of
> it to an extent, but then the idle is crap. Is there a way to retard the
> vacuum advance? I think the entire problem is the monstrous vacuum coming
> off the Weber. Any help/advice would be greatly appreciated.
>
> --------------------
> 89 YJ 6 Low input, High output
> 95 YJ 4 High input, Low output
> 03 Rubicon - High Payment
>
>
09-01-2003, 04:22 PM
#4
Guest
Posts: n/a
Re: Timing advancing too much... solution?
Makesense - I have a bunch of jets here.
"Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> distributor. You need to get a bigger idle jet from Weber. Your problem is
> that you have to open your throttle plate too much to get the idle you
need,
> this exposes the "ported vacuum" for your advance. If you get a bigger jet
> you can close your throttle and only get vacuum when you hit the gas. The
> way to get around it is to set your timing with the advance connected, you
> will have a flat spot when accelerating but your idle and low end will be
> there. I had to go from a .70 to a .80 jet because of my headers.
>
> Scott
> 90YJ
>
>
> "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> >
> > Since I put the Weber on my 89 I've had this problem - set the initial
> > timing just right, and when the vacuum advance is re-connected , it will
> > advance too much at low speed under 4lo load causing piston-killing
> > detonation. I've tried retarding the initial timing and that takes care
of
> > it to an extent, but then the idle is crap. Is there a way to retard the
> > vacuum advance? I think the entire problem is the monstrous vacuum
coming
> > off the Weber. Any help/advice would be greatly appreciated.
> >
> > --------------------
> > 89 YJ 6 Low input, High output
> > 95 YJ 4 High input, Low output
> > 03 Rubicon - High Payment
> >
> >
>
>
"Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> distributor. You need to get a bigger idle jet from Weber. Your problem is
> that you have to open your throttle plate too much to get the idle you
need,
> this exposes the "ported vacuum" for your advance. If you get a bigger jet
> you can close your throttle and only get vacuum when you hit the gas. The
> way to get around it is to set your timing with the advance connected, you
> will have a flat spot when accelerating but your idle and low end will be
> there. I had to go from a .70 to a .80 jet because of my headers.
>
> Scott
> 90YJ
>
>
> "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> >
> > Since I put the Weber on my 89 I've had this problem - set the initial
> > timing just right, and when the vacuum advance is re-connected , it will
> > advance too much at low speed under 4lo load causing piston-killing
> > detonation. I've tried retarding the initial timing and that takes care
of
> > it to an extent, but then the idle is crap. Is there a way to retard the
> > vacuum advance? I think the entire problem is the monstrous vacuum
coming
> > off the Weber. Any help/advice would be greatly appreciated.
> >
> > --------------------
> > 89 YJ 6 Low input, High output
> > 95 YJ 4 High input, Low output
> > 03 Rubicon - High Payment
> >
> >
>
>
09-01-2003, 04:22 PM
#5
Guest
Posts: n/a
Re: Timing advancing too much... solution?
Makesense - I have a bunch of jets here.
"Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> distributor. You need to get a bigger idle jet from Weber. Your problem is
> that you have to open your throttle plate too much to get the idle you
need,
> this exposes the "ported vacuum" for your advance. If you get a bigger jet
> you can close your throttle and only get vacuum when you hit the gas. The
> way to get around it is to set your timing with the advance connected, you
> will have a flat spot when accelerating but your idle and low end will be
> there. I had to go from a .70 to a .80 jet because of my headers.
>
> Scott
> 90YJ
>
>
> "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> >
> > Since I put the Weber on my 89 I've had this problem - set the initial
> > timing just right, and when the vacuum advance is re-connected , it will
> > advance too much at low speed under 4lo load causing piston-killing
> > detonation. I've tried retarding the initial timing and that takes care
of
> > it to an extent, but then the idle is crap. Is there a way to retard the
> > vacuum advance? I think the entire problem is the monstrous vacuum
coming
> > off the Weber. Any help/advice would be greatly appreciated.
> >
> > --------------------
> > 89 YJ 6 Low input, High output
> > 95 YJ 4 High input, Low output
> > 03 Rubicon - High Payment
> >
> >
>
>
"Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> distributor. You need to get a bigger idle jet from Weber. Your problem is
> that you have to open your throttle plate too much to get the idle you
need,
> this exposes the "ported vacuum" for your advance. If you get a bigger jet
> you can close your throttle and only get vacuum when you hit the gas. The
> way to get around it is to set your timing with the advance connected, you
> will have a flat spot when accelerating but your idle and low end will be
> there. I had to go from a .70 to a .80 jet because of my headers.
>
> Scott
> 90YJ
>
>
> "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> >
> > Since I put the Weber on my 89 I've had this problem - set the initial
> > timing just right, and when the vacuum advance is re-connected , it will
> > advance too much at low speed under 4lo load causing piston-killing
> > detonation. I've tried retarding the initial timing and that takes care
of
> > it to an extent, but then the idle is crap. Is there a way to retard the
> > vacuum advance? I think the entire problem is the monstrous vacuum
coming
> > off the Weber. Any help/advice would be greatly appreciated.
> >
> > --------------------
> > 89 YJ 6 Low input, High output
> > 95 YJ 4 High input, Low output
> > 03 Rubicon - High Payment
> >
> >
>
>
09-01-2003, 05:41 PM
#6
Guest
Posts: n/a
Re: Timing advancing too much... solution?
The springs inside can wear out too.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Jeepaholic wrote:
>
> Makesense - I have a bunch of jets here.
>
> "Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
> news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> > I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> > distributor. You need to get a bigger idle jet from Weber. Your problem is
> > that you have to open your throttle plate too much to get the idle you
> need,
> > this exposes the "ported vacuum" for your advance. If you get a bigger jet
> > you can close your throttle and only get vacuum when you hit the gas. The
> > way to get around it is to set your timing with the advance connected, you
> > will have a flat spot when accelerating but your idle and low end will be
> > there. I had to go from a .70 to a .80 jet because of my headers.
> >
> > Scott
> > 90YJ
> >
> >
> > "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> > news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> > >
> > > Since I put the Weber on my 89 I've had this problem - set the initial
> > > timing just right, and when the vacuum advance is re-connected , it will
> > > advance too much at low speed under 4lo load causing piston-killing
> > > detonation. I've tried retarding the initial timing and that takes care
> of
> > > it to an extent, but then the idle is crap. Is there a way to retard the
> > > vacuum advance? I think the entire problem is the monstrous vacuum
> coming
> > > off the Weber. Any help/advice would be greatly appreciated.
> > >
> > > --------------------
> > > 89 YJ 6 Low input, High output
> > > 95 YJ 4 High input, Low output
> > > 03 Rubicon - High Payment
> > >
> > >
> >
> >
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Jeepaholic wrote:
>
> Makesense - I have a bunch of jets here.
>
> "Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
> news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> > I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> > distributor. You need to get a bigger idle jet from Weber. Your problem is
> > that you have to open your throttle plate too much to get the idle you
> need,
> > this exposes the "ported vacuum" for your advance. If you get a bigger jet
> > you can close your throttle and only get vacuum when you hit the gas. The
> > way to get around it is to set your timing with the advance connected, you
> > will have a flat spot when accelerating but your idle and low end will be
> > there. I had to go from a .70 to a .80 jet because of my headers.
> >
> > Scott
> > 90YJ
> >
> >
> > "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> > news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> > >
> > > Since I put the Weber on my 89 I've had this problem - set the initial
> > > timing just right, and when the vacuum advance is re-connected , it will
> > > advance too much at low speed under 4lo load causing piston-killing
> > > detonation. I've tried retarding the initial timing and that takes care
> of
> > > it to an extent, but then the idle is crap. Is there a way to retard the
> > > vacuum advance? I think the entire problem is the monstrous vacuum
> coming
> > > off the Weber. Any help/advice would be greatly appreciated.
> > >
> > > --------------------
> > > 89 YJ 6 Low input, High output
> > > 95 YJ 4 High input, Low output
> > > 03 Rubicon - High Payment
> > >
> > >
> >
> >
09-01-2003, 05:41 PM
#7
Guest
Posts: n/a
Re: Timing advancing too much... solution?
The springs inside can wear out too.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Jeepaholic wrote:
>
> Makesense - I have a bunch of jets here.
>
> "Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
> news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> > I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> > distributor. You need to get a bigger idle jet from Weber. Your problem is
> > that you have to open your throttle plate too much to get the idle you
> need,
> > this exposes the "ported vacuum" for your advance. If you get a bigger jet
> > you can close your throttle and only get vacuum when you hit the gas. The
> > way to get around it is to set your timing with the advance connected, you
> > will have a flat spot when accelerating but your idle and low end will be
> > there. I had to go from a .70 to a .80 jet because of my headers.
> >
> > Scott
> > 90YJ
> >
> >
> > "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> > news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> > >
> > > Since I put the Weber on my 89 I've had this problem - set the initial
> > > timing just right, and when the vacuum advance is re-connected , it will
> > > advance too much at low speed under 4lo load causing piston-killing
> > > detonation. I've tried retarding the initial timing and that takes care
> of
> > > it to an extent, but then the idle is crap. Is there a way to retard the
> > > vacuum advance? I think the entire problem is the monstrous vacuum
> coming
> > > off the Weber. Any help/advice would be greatly appreciated.
> > >
> > > --------------------
> > > 89 YJ 6 Low input, High output
> > > 95 YJ 4 High input, Low output
> > > 03 Rubicon - High Payment
> > >
> > >
> >
> >
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Jeepaholic wrote:
>
> Makesense - I have a bunch of jets here.
>
> "Foot Loose" <footloose61@ NOSPAM hotmail.com> wrote in message
> news:CxJ4b.4371$cQ1.1333745@kent.svc.tds.net...
> > I had the same problem. My set up is 90YJ 258, headers, Weber carb, HEI
> > distributor. You need to get a bigger idle jet from Weber. Your problem is
> > that you have to open your throttle plate too much to get the idle you
> need,
> > this exposes the "ported vacuum" for your advance. If you get a bigger jet
> > you can close your throttle and only get vacuum when you hit the gas. The
> > way to get around it is to set your timing with the advance connected, you
> > will have a flat spot when accelerating but your idle and low end will be
> > there. I had to go from a .70 to a .80 jet because of my headers.
> >
> > Scott
> > 90YJ
> >
> >
> > "Jeepaholic" <jeepahoilcs@earthlink.net> wrote in message
> > news:fII4b.4582$Lk5.2533@newsread3.news.pas.earthl ink.net...
> > > 89 YJ I6, bored .30 over, RV cam, Weber 38DGES
> > >
> > > Since I put the Weber on my 89 I've had this problem - set the initial
> > > timing just right, and when the vacuum advance is re-connected , it will
> > > advance too much at low speed under 4lo load causing piston-killing
> > > detonation. I've tried retarding the initial timing and that takes care
> of
> > > it to an extent, but then the idle is crap. Is there a way to retard the
> > > vacuum advance? I think the entire problem is the monstrous vacuum
> coming
> > > off the Weber. Any help/advice would be greatly appreciated.
> > >
> > > --------------------
> > > 89 YJ 6 Low input, High output
> > > 95 YJ 4 High input, Low output
> > > 03 Rubicon - High Payment
> > >
> > >
> >
> >
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