No Measurable Vacuum at Idle???
02-23-2004, 09:22 AM
#21
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
You are tagging a ported vacuum source.
This gives you timing advance with rpm and in my opinion give the engine
the best 'punch'.
On the newer ones, they use a manifold vacuum to give the engine a
smoother idle for the pollution sniffer and had a computer actually
adjusting the timing advance.
When I dumped the computer, I switched over to the ported advance. On
manifold vacuum timing my engine has a dead spot when you punch the gas,
it bogs down and slowly recovers.
With the timing ported and a punch on the gas pedal, it just perks up
and lights up my 33" mud tires in both 1st and 2nd and takes off like a
scalded cat.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
This gives you timing advance with rpm and in my opinion give the engine
the best 'punch'.
On the newer ones, they use a manifold vacuum to give the engine a
smoother idle for the pollution sniffer and had a computer actually
adjusting the timing advance.
When I dumped the computer, I switched over to the ported advance. On
manifold vacuum timing my engine has a dead spot when you punch the gas,
it bogs down and slowly recovers.
With the timing ported and a punch on the gas pedal, it just perks up
and lights up my 33" mud tires in both 1st and 2nd and takes off like a
scalded cat.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
02-23-2004, 09:22 AM
#22
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
You are tagging a ported vacuum source.
This gives you timing advance with rpm and in my opinion give the engine
the best 'punch'.
On the newer ones, they use a manifold vacuum to give the engine a
smoother idle for the pollution sniffer and had a computer actually
adjusting the timing advance.
When I dumped the computer, I switched over to the ported advance. On
manifold vacuum timing my engine has a dead spot when you punch the gas,
it bogs down and slowly recovers.
With the timing ported and a punch on the gas pedal, it just perks up
and lights up my 33" mud tires in both 1st and 2nd and takes off like a
scalded cat.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
This gives you timing advance with rpm and in my opinion give the engine
the best 'punch'.
On the newer ones, they use a manifold vacuum to give the engine a
smoother idle for the pollution sniffer and had a computer actually
adjusting the timing advance.
When I dumped the computer, I switched over to the ported advance. On
manifold vacuum timing my engine has a dead spot when you punch the gas,
it bogs down and slowly recovers.
With the timing ported and a punch on the gas pedal, it just perks up
and lights up my 33" mud tires in both 1st and 2nd and takes off like a
scalded cat.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
02-23-2004, 09:33 AM
#23
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
I just checked my book and it looks like you have 2 vacuum nipples. The
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
02-23-2004, 09:33 AM
#24
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
I just checked my book and it looks like you have 2 vacuum nipples. The
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
02-23-2004, 09:33 AM
#25
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
I just checked my book and it looks like you have 2 vacuum nipples. The
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
bottom one is the 'spark' port and the upper one is the 'egr' port.
That implies both are ported vacuum to me.
Mike
Drink wrote:
>
> Here's something I've pondered for years...
> When I tune the Jeep, I have no measurable vacuum at idle. If I raise the
> RPM above idle around 1,000 and up (revving high), it shows plenty of
> vacuum; 16 inches or so I think. I have a '76 258 with the ole' Carter YF
> carb with minimal emissions. In fact, the only thing I have is the vacuum
> advance ported from the carb, PCV to manifold, canister to manifold and
> canister pulling vapor from around the bowl. The intake manifold ports were
> all plugged with bungs. I'm describing the plumbing from memory. So, don't
> quote me but I'm pretty sure that's it. The engine runs just fine besides
> being cold natured. but, it ain't a problem down here in Florida.
> All the hoses are in fine shape and I can't find any leaks anywhere. I've
> torqued the manifolds and they've never leaked either through various head
> and manifold swaps. The carb's tight too. So, what's the deal with an
> otherwise healthy engine that shows good compression. The distributor's new
> and I've ruled out a ruptured diaphragm. What could it be? Am I being
> stupid and there shouldn't be any measured vacuum at idle?
> o_o_o_o
> Best Regards, /| ,[_____],
> Jim, WP3JQ |¯¯¯L --O|||||||O-
> ()_)¯()_) ¯¯¯¯¯ )_)
> EM60qk 30.447439N 086.628959W
02-23-2004, 02:00 PM
#26
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
You know the Exhaust Gas Recirculation valve may only work
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
02-23-2004, 02:00 PM
#27
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
You know the Exhaust Gas Recirculation valve may only work
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
02-23-2004, 02:00 PM
#28
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
You know the Exhaust Gas Recirculation valve may only work
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
correctly using full manifold vacuum.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> I just checked my book and it looks like you have 2 vacuum nipples. The
> bottom one is the 'spark' port and the upper one is the 'egr' port.
> That implies both are ported vacuum to me.
>
> Mike
02-23-2004, 02:19 PM
#29
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
The 258 one uses ported vacuum.
Mike
"L.W.(ßill) ------ III" wrote:
>
> You know the Exhaust Gas Recirculation valve may only work
> correctly using full manifold vacuum.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just checked my book and it looks like you have 2 vacuum nipples. The
> > bottom one is the 'spark' port and the upper one is the 'egr' port.
> > That implies both are ported vacuum to me.
> >
> > Mike
Mike
"L.W.(ßill) ------ III" wrote:
>
> You know the Exhaust Gas Recirculation valve may only work
> correctly using full manifold vacuum.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just checked my book and it looks like you have 2 vacuum nipples. The
> > bottom one is the 'spark' port and the upper one is the 'egr' port.
> > That implies both are ported vacuum to me.
> >
> > Mike
02-23-2004, 02:19 PM
#30
Guest
Posts: n/a
Re: No Measurable Vacuum at Idle???
The 258 one uses ported vacuum.
Mike
"L.W.(ßill) ------ III" wrote:
>
> You know the Exhaust Gas Recirculation valve may only work
> correctly using full manifold vacuum.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just checked my book and it looks like you have 2 vacuum nipples. The
> > bottom one is the 'spark' port and the upper one is the 'egr' port.
> > That implies both are ported vacuum to me.
> >
> > Mike
Mike
"L.W.(ßill) ------ III" wrote:
>
> You know the Exhaust Gas Recirculation valve may only work
> correctly using full manifold vacuum.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > I just checked my book and it looks like you have 2 vacuum nipples. The
> > bottom one is the 'spark' port and the upper one is the 'egr' port.
> > That implies both are ported vacuum to me.
> >
> > Mike
