[Diy_efi] Hesitation

Wed Jun 28 14:31:46 UTC 2006

And yes, obviously make sure there are no leaks, but, a new chunk of  hose
to go from the manifold and into the MAP wouldn't hurt anyone, and at 50
cents a foot, why not?  i'd also shoot some carb cleaner in there to make
sure its not clogged with carbon..

On 6/28/06, Jim Butterfield <jimbutterfield at yahoo.com> wrote:
>
> Ditto.... Ditto.... back in the day when I worked at Firestone, we'd see
> little chevys come in with the 2.0L engines and they had an elbow tube
> from map to the manifold... and the elbow would either crack out and leak
> vacuum or plug up with carbon and such...
>
>
>
> dgilbert78 at juno.com wrote:
>   Hello: If you have a MAP system make absolutely sure that the vacuum to
> the MAP is on time, not delayed. Lots of times on GM TBI units (possibly
> others) the vacuum port to the MAP becomes plugged with carbon to the
> point that the orface is so small that the vacuum is delayed to the MAP,
> this will without a doubt cause hessitation on quick throttle opening. On
> slow no load throttle opening the vacuum is fast enough to run the MAP
> and the problem is not present. There is no test for this unless the MAP
> port is completely plugged, then it is obvious, because you will get no
> MAP change. I had to pull the TPI and rod the port and choke cleaner it.
> After that no more hesitation, Probably any problem with the vacuum hose
> to the MAP would cause a similiar problem,
> good luck
> Darryl...
> On Tue, 27 Jun 2006 20:07:53 -0700 (PDT) Scott Scott
> writes:
> > Thanks for the reply. So the EFI system creates its
> > own virtual accelerator pump of sorts? Makes sense, a
> > little extra fuel to compensate for the higher demand.
> >
> >
> > What do I do to diagnose this and correct it?
> >
> > Thanks
> >
> >
> > --- Mike wrote:
> >
> > > Any transient mixture enrichment on rate of change
> > > of throttle position ?
> > >
> > > Even the oldie hitachi/bosch ecu reads rate of
> > > change of throttle
> > > position and intersperses extra injection pulses to
> > > act like the
> > > old accelerator pump of the carbie days, seems like
> > > you have
> > > that issue from your description as you report its
> > > more than
> > > noticable when on load - that is when its most
> > > apparent...
> > >
> > > rgds
> > >
> > > Mike
> > >
> > >
> > >
> > > At 01:33 AM 6/28/06, you wrote:
> > > >I just put a TBI setup from a 1991 Silverado onto a
> > > >1969 Mustang with a 302 (2bbl). It runs well,
> > > idles
> > > >smoothly, but I have a couple of issues.
> > > >
> > > >1?It has some hesitation on acceleration. Not when
> > > I
> > > >rev it in the garage, but when its in gear. Timing
> > > is
> > > >currently set at 10 degrees BTDC (base timing), I'm
> > > >thinking of adding a little more advance to it.
> > > Any
> > > >other ideas? It actually stalls out sometimes when
> > > I
> > > >try to make a fast getaway.
> > > >
> > > >2?I put the ECU under the dash. I reached in and
> > > put
> > > >my hand on the box after I had been driving a
> > > while,
> > > >and it was VERY hot to the touch. I almost
> > > couldn't
> > > >hold on to it. Is this a normal operating
> > > condition
> > > >of the GM ECU?
> > > >
> > > >Any tips are appreciated!
> > > >
> > > >
> > > >__________________________________________________
> > > >Do You Yahoo!?
> > > >Tired of spam? Yahoo! Mail has the best spam
> > > protection around
> > > >http://mail.yahoo.com
> > > >_______________________________________________
> > > >Diy_efi mailing list
> > > >Diy_efi at diy-efi.org
> > > >http://lists.diy-efi.org/mailman/listinfo/diy_efi
> > >
> > >
> > > Regards from
> > >
> > >
> > > Mike
> > > Perth, Western Australia
> > > VL Commodore Fuse Rail that wont warp or melt !
> > > Twin tyres for most sedans, trikes and motorcycle
> > > sidecars
> > > http://niche.iinet.net.au
> > > _______________________________________________
> > > Diy_efi mailing list
> > > Diy_efi at diy-efi.org
> > > http://lists.diy-efi.org/mailman/listinfo/diy_efi
> > >
> >
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam protection around
> > http://mail.yahoo.com
> > _______________________________________________
> > Diy_efi mailing list
> > Diy_efi at diy-efi.org
> > http://lists.diy-efi.org/mailman/listinfo/diy_efi
> >
> >
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>
>
>
> ---------------------------------
> Want to be your own boss? Learn how on  Yahoo! Small Business.
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>

-- 
Sincerely,
Lee M. Lemoine
KB1NQI  - Amateur Radio
http://www.turbochargedsoul.com/
'06 Subaru Legacy GT Limited - 250/250 AWD 5EAT
'93 Chevy Cavalier Z24 Convertible - 300/330 FWD 5MT (Mclaren Turbo!)