sorting out my proflo, one issue

Jason Haines jhaines15 at home.com
Wed Jul 25 14:09:10 GMT 2001


Do you have a way to check air fuel ratio (other than the rich/lean
indicator in the Pro Flo)? When you get the Pro Flo O2 sensor installed,
check to see if you are going leaner than 14.7 (red light)? How about fuel
pressure - any chance you are loosing fuel pressure under those conditions?
I am working with a Pro Flo right now and I am chasing a transient fuel
condition (goes lean) that will not respond to global or transient fuel
changes (I too have gone as high as 20% without any change in the
condition). It looks like the fuel pressure is dropping when the lean
condition occurs. The other less likely issue could also be fuel rail
"hammer" - does the fuel pressure start jumping up and down very quickly
when the problem occurs?


Jason


> Ross Corrigan wrote:
>
> > I just got my 1980 280zx running with the edelbrock proflo unit sitting
> > atop my '98 full roller .520/.523 cammed small block chevy.
> >
> > The chip I got with it is meant for the ZZ4 cam I'm running as per the
GM
> > crate motor but I've increased the potential with mixed rockers and
> > superior heads....but conversely my exhaust is somewhat poor with a
sharp
> > 90 and a shallow low rise inlet air setup.
> >
> > The 'issue': 'rough' possibly stumbling from 1000rpm on up to 2000 rpm
at
> > mild to mid throttle (ie. if WOT from a stop it's fine and hauls
ass)....if
> > not WOT from idle and then throttle fed in the whole car shakes as it
> > 'fights' to 2500rpm or so and then runs fine.
> >
> > I tried each of the following as an alteration to the base chip,
resetting
> > to the base chip b/t each list of points
> >
> > -I've raised the global fuel modifier by 2%/4%/6% right on up to 20%
with
> > no change.
> > reset
> > -raised the fuel at 12" vaccuum by 6% at 1000rpm/2000rpm/3000rpm, no
change
> > reset
> > -raised spark by 6 degrees at 1000rpm/2000rpm/3000rpm, no change
> > reset
> > -decreased global fuel modifier by 2%/4%/.......on up to -14% for
> > 1000,2000,3000 rpm (it smooths the curves b/t the points I give it and
the
> > ones unaltered)
> >
> > (I only got it running 2 days ago and am now driving it to work.  I
really
> > HOPE to get the o2 sensor installed this Saturday which should help me
know
> > more......the system won't calculate an a/f but it does have a rich/lean
> > light for some help....)
> >
> > Any ideas on what it can be?  At cruise it'll have b/t 20.5-22 " vaccuum
> > depending and in idle out of gear it's at 17-18" vaccuum and once in
gear
> > stopped it drops to 15.5-16" of vaccuum (idle isn't so steady....I'm
> > thinking it's due to one exhaust pipe being more restrictive so I KNOW
one
> > side runs richer than the other, older plugs said that steadily).
> >
> > It's sitting at 25 degrees spark at idle as well.
> >
> > Thanks in advance.
> > Ross Corrigan  /  Vancouver, Canada      , yes 4.11 R200's once again
available
> >
> > Ahh, finished with that inferno of work and returning back to the
lifelong
> > ahem, physics experiments :) ) )
> >
> > mailto:280zx at home.com      ICQ # 11549358
> > http://207.212.212.139/~corrigan/gearheads/pics/wheels/sirbg.jpg
where a
> > Z belongs
>
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