Re: fuel mileage drop problem solved!
 

Simon Juncal wrote:
>
> > And I have yet to see any back yard mechanic have an 'air fuel mix
> > gauge'. The CJ's are Carburated Jeeps that were manually tuned since
> > they came out in 1949. Only since the sad demise of mechanics and the
> > rise of 'technicians' that only know what a computer tells them is wrong
> > do you have tools like that.
>
> It's not a computer Mike, everything that lights up and is attached to
> sensors isn't necessarilly a computer... It's a scientific measuring
> device for combustion temps that can tell you if you're running too lean
> or wasting gas (and POWER) by running too rich. It's a HELL of a lot
> more accurate than your gut feeling, and it's WAY WAY freakin more
> accurate than your "hope" technique.
>
> If "computers" and scientific data providing guages caused the demise of
> mechanical yokles and non-adapting-stuck-in-the-past technophobes then
> the world is a better place...
>
> --

What billy ray said....

Plus, the OP is trying to make a carb behave by adjusting the pins on
the 'stepper' motor. This means he has something like 4 or 5 different
static places or 'steps' to put the pins on.

If he had the idle mix screws in the equation, my answer would have been
different than telling him to put it back 'like the factory' originally
set it with the pins in the center.....

I guess if all you know is a computer printout, this doesn't make any
sense to you, but putting it back 'factory' makes perfect sense to
me....

Too bad computers seem to make people forget the basics....

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)

Re: fuel mileage drop problem solved!
 

Simon Juncal wrote:
>
> > And I have yet to see any back yard mechanic have an 'air fuel mix
> > gauge'. The CJ's are Carburated Jeeps that were manually tuned since
> > they came out in 1949. Only since the sad demise of mechanics and the
> > rise of 'technicians' that only know what a computer tells them is wrong
> > do you have tools like that.
>
> It's not a computer Mike, everything that lights up and is attached to
> sensors isn't necessarilly a computer... It's a scientific measuring
> device for combustion temps that can tell you if you're running too lean
> or wasting gas (and POWER) by running too rich. It's a HELL of a lot
> more accurate than your gut feeling, and it's WAY WAY freakin more
> accurate than your "hope" technique.
>
> If "computers" and scientific data providing guages caused the demise of
> mechanical yokles and non-adapting-stuck-in-the-past technophobes then
> the world is a better place...
>
> --

What billy ray said....

Plus, the OP is trying to make a carb behave by adjusting the pins on
the 'stepper' motor. This means he has something like 4 or 5 different
static places or 'steps' to put the pins on.

If he had the idle mix screws in the equation, my answer would have been
different than telling him to put it back 'like the factory' originally
set it with the pins in the center.....

I guess if all you know is a computer printout, this doesn't make any
sense to you, but putting it back 'factory' makes perfect sense to
me....

Too bad computers seem to make people forget the basics....

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)

Re: fuel mileage drop problem solved!
 

Simon Juncal wrote:
>
> > And I have yet to see any back yard mechanic have an 'air fuel mix
> > gauge'. The CJ's are Carburated Jeeps that were manually tuned since
> > they came out in 1949. Only since the sad demise of mechanics and the
> > rise of 'technicians' that only know what a computer tells them is wrong
> > do you have tools like that.
>
> It's not a computer Mike, everything that lights up and is attached to
> sensors isn't necessarilly a computer... It's a scientific measuring
> device for combustion temps that can tell you if you're running too lean
> or wasting gas (and POWER) by running too rich. It's a HELL of a lot
> more accurate than your gut feeling, and it's WAY WAY freakin more
> accurate than your "hope" technique.
>
> If "computers" and scientific data providing guages caused the demise of
> mechanical yokles and non-adapting-stuck-in-the-past technophobes then
> the world is a better place...
>
> --

What billy ray said....

Plus, the OP is trying to make a carb behave by adjusting the pins on
the 'stepper' motor. This means he has something like 4 or 5 different
static places or 'steps' to put the pins on.

If he had the idle mix screws in the equation, my answer would have been
different than telling him to put it back 'like the factory' originally
set it with the pins in the center.....

I guess if all you know is a computer printout, this doesn't make any
sense to you, but putting it back 'factory' makes perfect sense to
me....

Too bad computers seem to make people forget the basics....

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)

Re: fuel mileage drop problem solved!
 

When you get your screws open, (You can flip the carb upside down and
cut 1/8" off the block where the screws are or drill in from the side to
pop the blocks out or if they are tin, just use a sharp punch to get
them out) you can put the pins back in and set the mix like a 'normal'
carb.

Just FYI, the idle mix screws do affect the mix at idle, but that tends
to have an effect all the way up. The stepper pins affect the air mix
through the whole throttle range. They work (have effect) at speed
also, via input from the O2 sensor and computer.

I go for a best lean idle mix. I start with a warm engine and the
screws both out about 5 turns and set the rpm at 600- 700. I then turn
them 1/4 turn in each, then give the throttle a rev, then another 1/4
turn. I continue while revving it between turns until the engine get a
lean stumble. You will hear it. I them back them out 1/4 turn from
there and she just purrs.

As you are doing this the rpm will change up normally. You are supposed
to stop and drop it back down ending up at 600-650 final. 500 is pretty
low.

The emissions sniffer likes them to have that lean rumble so I leave it
like that, 1/4 turn lean on both screws, come emissions time.

Getting the mix right will do wonders for the vacuum.

Mike

bobvonbob wrote:
>
> umm... appears i set off a little bit of a firestorm here...
> anyway, yes mike the screws are still blanked off - until sunday at
> least when i will be pulling the carb to change out the rounded
> mounting nuts with new hardened ones. i am hoping that adjusting the
> idle screws will even out my idle somewhat - it still lopes a bit from
> say 500-600 rpms...
> BUT wait mike, i thought that the idle mixture screws only affected the
> mixture AT IDLE! so running lean on the highway or at > ~1200 rpm
> wouldnt be affected by their position at all... correct? in any case
> she's been running like this for about 5 of the last 6 months without
> any noticable issues. additionally, i would suspect that if it was
> running so lean that i might hole a piston i'd be noticing a little
> backfire on the overrun etc etc.
> oh yeah - i DONT have a carb mixture measurement device, whatever it
> is... i have seen vacuum gauges for doing carb 'timing' adjustment on
> motorcycles with multiple carbs but otherwise i dont know any other way
> of adjusting the damn things besides seat-of-the-pants, old-school,
> shade-tree, guestimation. not to say that that's my preferred method -
> just the only option i currently have. if anyone with a carb
> thing-a-majig wants to come and help me tune this sucker on sunday by
> all means - come on by!
> cheers,
> bennett

Re: fuel mileage drop problem solved!
 

When you get your screws open, (You can flip the carb upside down and
cut 1/8" off the block where the screws are or drill in from the side to
pop the blocks out or if they are tin, just use a sharp punch to get
them out) you can put the pins back in and set the mix like a 'normal'
carb.

Just FYI, the idle mix screws do affect the mix at idle, but that tends
to have an effect all the way up. The stepper pins affect the air mix
through the whole throttle range. They work (have effect) at speed
also, via input from the O2 sensor and computer.

I go for a best lean idle mix. I start with a warm engine and the
screws both out about 5 turns and set the rpm at 600- 700. I then turn
them 1/4 turn in each, then give the throttle a rev, then another 1/4
turn. I continue while revving it between turns until the engine get a
lean stumble. You will hear it. I them back them out 1/4 turn from
there and she just purrs.

As you are doing this the rpm will change up normally. You are supposed
to stop and drop it back down ending up at 600-650 final. 500 is pretty
low.

The emissions sniffer likes them to have that lean rumble so I leave it
like that, 1/4 turn lean on both screws, come emissions time.

Getting the mix right will do wonders for the vacuum.

Mike

bobvonbob wrote:
>
> umm... appears i set off a little bit of a firestorm here...
> anyway, yes mike the screws are still blanked off - until sunday at
> least when i will be pulling the carb to change out the rounded
> mounting nuts with new hardened ones. i am hoping that adjusting the
> idle screws will even out my idle somewhat - it still lopes a bit from
> say 500-600 rpms...
> BUT wait mike, i thought that the idle mixture screws only affected the
> mixture AT IDLE! so running lean on the highway or at > ~1200 rpm
> wouldnt be affected by their position at all... correct? in any case
> she's been running like this for about 5 of the last 6 months without
> any noticable issues. additionally, i would suspect that if it was
> running so lean that i might hole a piston i'd be noticing a little
> backfire on the overrun etc etc.
> oh yeah - i DONT have a carb mixture measurement device, whatever it
> is... i have seen vacuum gauges for doing carb 'timing' adjustment on
> motorcycles with multiple carbs but otherwise i dont know any other way
> of adjusting the damn things besides seat-of-the-pants, old-school,
> shade-tree, guestimation. not to say that that's my preferred method -
> just the only option i currently have. if anyone with a carb
> thing-a-majig wants to come and help me tune this sucker on sunday by
> all means - come on by!
> cheers,
> bennett

Re: fuel mileage drop problem solved!
 

When you get your screws open, (You can flip the carb upside down and
cut 1/8" off the block where the screws are or drill in from the side to
pop the blocks out or if they are tin, just use a sharp punch to get
them out) you can put the pins back in and set the mix like a 'normal'
carb.

Just FYI, the idle mix screws do affect the mix at idle, but that tends
to have an effect all the way up. The stepper pins affect the air mix
through the whole throttle range. They work (have effect) at speed
also, via input from the O2 sensor and computer.

I go for a best lean idle mix. I start with a warm engine and the
screws both out about 5 turns and set the rpm at 600- 700. I then turn
them 1/4 turn in each, then give the throttle a rev, then another 1/4
turn. I continue while revving it between turns until the engine get a
lean stumble. You will hear it. I them back them out 1/4 turn from
there and she just purrs.

As you are doing this the rpm will change up normally. You are supposed
to stop and drop it back down ending up at 600-650 final. 500 is pretty
low.

The emissions sniffer likes them to have that lean rumble so I leave it
like that, 1/4 turn lean on both screws, come emissions time.

Getting the mix right will do wonders for the vacuum.

Mike

bobvonbob wrote:
>
> umm... appears i set off a little bit of a firestorm here...
> anyway, yes mike the screws are still blanked off - until sunday at
> least when i will be pulling the carb to change out the rounded
> mounting nuts with new hardened ones. i am hoping that adjusting the
> idle screws will even out my idle somewhat - it still lopes a bit from
> say 500-600 rpms...
> BUT wait mike, i thought that the idle mixture screws only affected the
> mixture AT IDLE! so running lean on the highway or at > ~1200 rpm
> wouldnt be affected by their position at all... correct? in any case
> she's been running like this for about 5 of the last 6 months without
> any noticable issues. additionally, i would suspect that if it was
> running so lean that i might hole a piston i'd be noticing a little
> backfire on the overrun etc etc.
> oh yeah - i DONT have a carb mixture measurement device, whatever it
> is... i have seen vacuum gauges for doing carb 'timing' adjustment on
> motorcycles with multiple carbs but otherwise i dont know any other way
> of adjusting the damn things besides seat-of-the-pants, old-school,
> shade-tree, guestimation. not to say that that's my preferred method -
> just the only option i currently have. if anyone with a carb
> thing-a-majig wants to come and help me tune this sucker on sunday by
> all means - come on by!
> cheers,
> bennett

Re: fuel mileage drop problem solved!
 

When you get your screws open, (You can flip the carb upside down and
cut 1/8" off the block where the screws are or drill in from the side to
pop the blocks out or if they are tin, just use a sharp punch to get
them out) you can put the pins back in and set the mix like a 'normal'
carb.

Just FYI, the idle mix screws do affect the mix at idle, but that tends
to have an effect all the way up. The stepper pins affect the air mix
through the whole throttle range. They work (have effect) at speed
also, via input from the O2 sensor and computer.

I go for a best lean idle mix. I start with a warm engine and the
screws both out about 5 turns and set the rpm at 600- 700. I then turn
them 1/4 turn in each, then give the throttle a rev, then another 1/4
turn. I continue while revving it between turns until the engine get a
lean stumble. You will hear it. I them back them out 1/4 turn from
there and she just purrs.

As you are doing this the rpm will change up normally. You are supposed
to stop and drop it back down ending up at 600-650 final. 500 is pretty
low.

The emissions sniffer likes them to have that lean rumble so I leave it
like that, 1/4 turn lean on both screws, come emissions time.

Getting the mix right will do wonders for the vacuum.

Mike

bobvonbob wrote:
>
> umm... appears i set off a little bit of a firestorm here...
> anyway, yes mike the screws are still blanked off - until sunday at
> least when i will be pulling the carb to change out the rounded
> mounting nuts with new hardened ones. i am hoping that adjusting the
> idle screws will even out my idle somewhat - it still lopes a bit from
> say 500-600 rpms...
> BUT wait mike, i thought that the idle mixture screws only affected the
> mixture AT IDLE! so running lean on the highway or at > ~1200 rpm
> wouldnt be affected by their position at all... correct? in any case
> she's been running like this for about 5 of the last 6 months without
> any noticable issues. additionally, i would suspect that if it was
> running so lean that i might hole a piston i'd be noticing a little
> backfire on the overrun etc etc.
> oh yeah - i DONT have a carb mixture measurement device, whatever it
> is... i have seen vacuum gauges for doing carb 'timing' adjustment on
> motorcycles with multiple carbs but otherwise i dont know any other way
> of adjusting the damn things besides seat-of-the-pants, old-school,
> shade-tree, guestimation. not to say that that's my preferred method -
> just the only option i currently have. if anyone with a carb
> thing-a-majig wants to come and help me tune this sucker on sunday by
> all means - come on by!
> cheers,
> bennett

Re: fuel mileage drop problem solved!
 

thanks mike - you are the master of these 258/BBD setups as far as i
can tell.
thanks to everyone else as well - i'll be tearing the carb off tomorrow
and will report back after.
BTW mike - STILL no ported vacuum off the carb - thinking its a gasket
issue. we'll see soon enough. one thing tho - if i'm not getting any
advance from 1200-2500 rpm (or whatever the window is before the
mechanical takes over) then why is she still running so well? not that
she's gonna win any stump pulling contests or anything...
cheers,
bennett

Re: fuel mileage drop problem solved!
 

thanks mike - you are the master of these 258/BBD setups as far as i
can tell.
thanks to everyone else as well - i'll be tearing the carb off tomorrow
and will report back after.
BTW mike - STILL no ported vacuum off the carb - thinking its a gasket
issue. we'll see soon enough. one thing tho - if i'm not getting any
advance from 1200-2500 rpm (or whatever the window is before the
mechanical takes over) then why is she still running so well? not that
she's gonna win any stump pulling contests or anything...
cheers,
bennett

Re: fuel mileage drop problem solved!
 

thanks mike - you are the master of these 258/BBD setups as far as i
can tell.
thanks to everyone else as well - i'll be tearing the carb off tomorrow
and will report back after.
BTW mike - STILL no ported vacuum off the carb - thinking its a gasket
issue. we'll see soon enough. one thing tho - if i'm not getting any
advance from 1200-2500 rpm (or whatever the window is before the
mechanical takes over) then why is she still running so well? not that
she's gonna win any stump pulling contests or anything...
cheers,
bennett