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!
 

I was thinking on my setup and I believe if I have the stepper pins all
the way in that they can physically be jammed, that is one step farther
than the computer can set it the way the 'nutter' says to make the
computer 'full rich'. I also think I lost about 5 mpg if I am right. I
think I set the pins one click out or where the carbon mark on it
stopped which indicated the travel the computer had it doing and got my
nice 23 mpg or 11L/100 km for us Canadians, eh.

The engines are very forgiving for timing... Right now, when I goose
the throttle, my vacuum timing snaps to full instantly. I can watch it
move.

The emissions sticker says to have the vacuum off and plugged and to
have it at 1600 rpm when setting the timing. I was under the impression
the mechanical advance was full on at this point and the vacuum varies
it from there.

Stock it has manifold vacuum to the timing, not ported.

Have you read around this site?
http://home.sprynet.com/~dale02/ignmods.htm
http://home.sprynet.com/~dale02/list.htm

It is a good one.

Mike

bobvonbob wrote:
>
> 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!
 

I was thinking on my setup and I believe if I have the stepper pins all
the way in that they can physically be jammed, that is one step farther
than the computer can set it the way the 'nutter' says to make the
computer 'full rich'. I also think I lost about 5 mpg if I am right. I
think I set the pins one click out or where the carbon mark on it
stopped which indicated the travel the computer had it doing and got my
nice 23 mpg or 11L/100 km for us Canadians, eh.

The engines are very forgiving for timing... Right now, when I goose
the throttle, my vacuum timing snaps to full instantly. I can watch it
move.

The emissions sticker says to have the vacuum off and plugged and to
have it at 1600 rpm when setting the timing. I was under the impression
the mechanical advance was full on at this point and the vacuum varies
it from there.

Stock it has manifold vacuum to the timing, not ported.

Have you read around this site?
http://home.sprynet.com/~dale02/ignmods.htm
http://home.sprynet.com/~dale02/list.htm

It is a good one.

Mike

bobvonbob wrote:
>
> 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!
 

I was thinking on my setup and I believe if I have the stepper pins all
the way in that they can physically be jammed, that is one step farther
than the computer can set it the way the 'nutter' says to make the
computer 'full rich'. I also think I lost about 5 mpg if I am right. I
think I set the pins one click out or where the carbon mark on it
stopped which indicated the travel the computer had it doing and got my
nice 23 mpg or 11L/100 km for us Canadians, eh.

The engines are very forgiving for timing... Right now, when I goose
the throttle, my vacuum timing snaps to full instantly. I can watch it
move.

The emissions sticker says to have the vacuum off and plugged and to
have it at 1600 rpm when setting the timing. I was under the impression
the mechanical advance was full on at this point and the vacuum varies
it from there.

Stock it has manifold vacuum to the timing, not ported.

Have you read around this site?
http://home.sprynet.com/~dale02/ignmods.htm
http://home.sprynet.com/~dale02/list.htm

It is a good one.

Mike

bobvonbob wrote:
>
> 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!
 

I was thinking on my setup and I believe if I have the stepper pins all
the way in that they can physically be jammed, that is one step farther
than the computer can set it the way the 'nutter' says to make the
computer 'full rich'. I also think I lost about 5 mpg if I am right. I
think I set the pins one click out or where the carbon mark on it
stopped which indicated the travel the computer had it doing and got my
nice 23 mpg or 11L/100 km for us Canadians, eh.

The engines are very forgiving for timing... Right now, when I goose
the throttle, my vacuum timing snaps to full instantly. I can watch it
move.

The emissions sticker says to have the vacuum off and plugged and to
have it at 1600 rpm when setting the timing. I was under the impression
the mechanical advance was full on at this point and the vacuum varies
it from there.

Stock it has manifold vacuum to the timing, not ported.

Have you read around this site?
http://home.sprynet.com/~dale02/ignmods.htm
http://home.sprynet.com/~dale02/list.htm

It is a good one.

Mike

bobvonbob wrote:
>
> 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!
 

ahhh - i see... yes that makes sense. any advice on how to find the
proper position if there is no indication on the stepper motor shaft? i
dont think the thing will even move if i was to hook up the computer,
the shaft is so stiff.
another question: i set my timing originally to 8-9d BTDC at 1600 rpm,
but then after reading some posts on this list i reset the timing to
8-9d BTDC at 'idle' (approx 700rpm) - i have noticed somewhat of a drop
in power at higher rpms, but there are so many variables i'll have to
sort it all out tomorrow when i reset the carb gaskets...
but what rpms should i set the timing at?
cheers,
bennett

Re: fuel mileage drop problem solved!
 

ahhh - i see... yes that makes sense. any advice on how to find the
proper position if there is no indication on the stepper motor shaft? i
dont think the thing will even move if i was to hook up the computer,
the shaft is so stiff.
another question: i set my timing originally to 8-9d BTDC at 1600 rpm,
but then after reading some posts on this list i reset the timing to
8-9d BTDC at 'idle' (approx 700rpm) - i have noticed somewhat of a drop
in power at higher rpms, but there are so many variables i'll have to
sort it all out tomorrow when i reset the carb gaskets...
but what rpms should i set the timing at?
cheers,
bennett

Re: fuel mileage drop problem solved!
 

ahhh - i see... yes that makes sense. any advice on how to find the
proper position if there is no indication on the stepper motor shaft? i
dont think the thing will even move if i was to hook up the computer,
the shaft is so stiff.
another question: i set my timing originally to 8-9d BTDC at 1600 rpm,
but then after reading some posts on this list i reset the timing to
8-9d BTDC at 'idle' (approx 700rpm) - i have noticed somewhat of a drop
in power at higher rpms, but there are so many variables i'll have to
sort it all out tomorrow when i reset the carb gaskets...
but what rpms should i set the timing at?
cheers,
bennett

Re: fuel mileage drop problem solved!
 

ahhh - i see... yes that makes sense. any advice on how to find the
proper position if there is no indication on the stepper motor shaft? i
dont think the thing will even move if i was to hook up the computer,
the shaft is so stiff.
another question: i set my timing originally to 8-9d BTDC at 1600 rpm,
but then after reading some posts on this list i reset the timing to
8-9d BTDC at 'idle' (approx 700rpm) - i have noticed somewhat of a drop
in power at higher rpms, but there are so many variables i'll have to
sort it all out tomorrow when i reset the carb gaskets...
but what rpms should i set the timing at?
cheers,
bennett

Re: fuel mileage drop problem solved!
 

I set my timing at 650 rpm.

I 'think' it is one 'step' from full jam on the pins. I need to look at
mine so I will have look at where it sits. I will try to do that today,
but I am not moving well due to a change in drugs so I will have to see
what the pain level is. (got smucked up in a car accident a couple
years back)

The pins 'don't' move linearly or easily, they move on a 'stepper
motor'. You have to rock them to get them to go to the next step.

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)

bobvonbob wrote:
>
> ahhh - i see... yes that makes sense. any advice on how to find the
> proper position if there is no indication on the stepper motor shaft? i
> dont think the thing will even move if i was to hook up the computer,
> the shaft is so stiff.
> another question: i set my timing originally to 8-9d BTDC at 1600 rpm,
> but then after reading some posts on this list i reset the timing to
> 8-9d BTDC at 'idle' (approx 700rpm) - i have noticed somewhat of a drop
> in power at higher rpms, but there are so many variables i'll have to
> sort it all out tomorrow when i reset the carb gaskets...
> but what rpms should i set the timing at?
> cheers,
> bennett