Mike, maybe this is a stupid solution, if so I hope
the listers will explain why (I have some suspisions),
but why not give it one or 2 notches of choke at high
RPM's if that smooths it out? Thst leaves your low
rev mixture lean enough, and only enriches your high
rev mixture. Is this too simplistic??
Mike Harper
'66 1600
Charleston SC
--- datsunmike <datsunmike@nyc.rr.com> wrote:
> The formulation thing makes sense. If they are
> running MBTE it is an oxygen
> enricher for gasoline and would displace the
> gasoline so it's less bang for
> each ounce which is why you get worse gas mileage
> using it.
>
> Makes sense but . . . that still leaves me with a
> problem I have to fix.
>
> It definitely runs lean under steady throttle yet
> it's rich under
> acceleration and idle.
>
>
>
> ----- Original Message -----
> From: "Marc Sayer" <marcsayer@home.com>
> To: "Datsun Roadster List"
> <datsun-roadsters@autox.team.net>
> Sent: Friday, June 01, 2001 2:34 PM
> Subject: Re: Runnin Outta Gas
>
>
> > Its the needles. The profile is not right for the
> engine and at steady
> throttle
> > you are going lean. Since it does not lean out on
> hard acceleration (which
> is
> > enriched by the damper), it is not a fuel feed
> problem, which is the only
> other
> > thing that could cause this. Just to be sure,
> check your fuel pressure and
> float
> > level settings, but I'll bet they are within
> specs.
> >
> > Lots of folks are starting to run into a lean-out
> condition like this,
> even with
> > a stock engine and new stock needles. I am not
> sure why. We miked several
> new
> > needles to see if they were different from the
> older versions and they
> were
> > identical, within tolerances. Same engines, same
> carbs, same needles, but
> now
> > the cars are running lean??
> >
> > All I can think of is that something they have
> done to the gas is causing
> the
> > problem. I know that on my FI cars a change in gas
> formulation is very
> > noticeable. When I drive down to SoCal, my cars
> always run worse on CA gas
> than
> > they do on the OR gas. We get a different
> formulation up here. So I am
> wondering
> > if one of the newer additives, like say the MBTE
> or other "oxygenators" is
> > causing the fuel to act "leaner" somehow. Any
> chemists on the list that
> want to
> > try and answer this? Anyone else got any ideas?
> >
> > Nathan Ruffcorn wrote:
> > >
> > > Mike-
> > > I have always experienced the same problem on my
> 2L (N17 needles). Mine
> > > will keep power while aggresively accelerating,
> but if I hold a steady
> > > speed, it tends to surge. I hate to do this,
> but if I'm on the highway
> I
> > > pull the choke out part way. You may try this
> as it will help determine
> if
> > > you are truly getting enough fuel. The choke
> cleans it right up, but I
> hate
> > > the chance of running too rich and washing my
> cylinder walls. I've
> > > experimented with richening the carbs
> dramatically, but I get the same
> > > result (also required radically increasing idle
> speed setting to run-not
> too
> > > practical). At first I thought the needles were
> causing the lean
> condition,
> > > now I'm not so sure. Any thoughts?!
> > > BTW, manifold vaccum is good through all RPM's.
> > >
> > > Nathan
> > >
> > > ----- Original Message -----
> > > From: datsunmike <datsunmike@nyc.rr.com>
> > > To: Datsun Roadster List
> <datsun-roadsters@autox.team.net>
> > > Sent: Thursday, May 31, 2001 8:08 PM
> > > Subject: Runnin Outta Gas
> > >
> > > > Well I finally took my car out for a spin and
> it was great! I haven't
> > > driven
> > > > my car in over a year and I forgot what it
> felt like.
> > > >
> > > > While the car generally runs well I have no
> power above 4K RPMs. It
> feels
> > > > like it's running outta gas. I have 2L carbs
> with N17 needles and
> one1/4"
> > > > fuel line supplying both carbs from the Facet
> electric fuel pump to
> the
> > > > carbs. Do you think this could be the problem?
> I am not running lean
> as if
> > > I
> > > > richen it my idle deteriorates.
> > > >
> > > > Thanks for any help you can provide.
> > > >
> > > > Mike
> >
> > --
> > Marc Sayer
> > 82 280ZXT
> > 71 510 2.5 Trans Am vintage racer
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