J N's MiniRam backfire

[Bruce Plecan]

Don't take this as a "flame" but as just how I see where your at, and they
have pointed you

>     Some answers to your questions.  Car is an 89, 165 ecm $32B.  I have a
> chip from fastchip that I have been playing with that has modified MAF
> tables for a ported MAF.

You happen to know what the base BBC is?, and a copy of the MAF corrections.
I'd be interested in seeing what they did.
Why not start with the 6E code?.
So your not running screens?...

> I also tried my stock timing map and other
> various things.  I have been concentrating on my pump shot.  I called TPIS
> and they knew right away what my problem was.  They said I bet your
getting
> a big backfire through the intake.  They told me to modify the pump shot
> tables and that should do it. I increased the pump shot by 45% and that
did
> nothing.  I plan on increasing the pump shot more and experimenting.

I really beginning to sound like you generating a Alpha-N system, with the
MAF for trimming.
That is a huge huge amount.
Them "knowing" what the problem is so far isn't working.

>  Fuel
> pressure is set to 50 psi line off.  If you blip the gas, the pressure
> spikes to 50 like it should.

?
50 engine running, vac off,
then 50 running vac on, and blip the gas should see definetly more then 50
ie 53ish possibly more depending on cam.

TPIS suggested raising the pressure to 60 psi
> and I explained to them that for whatever reason, my multecs seem to start
> locking up at pressures over 50.  With that in mind, they suggested going
to
> a 24 pound injector.  I have a set of 30 pounders that I have been saving
> for the 396.  I figured that they were too large for a 350 with ported
heads
> and a slightly hot cam.

50-60 to get rid of a sneeze?.

Raising fuel pressure is a universal enrichment.
Just like changing Injector sizing......

There is a basic malfunction here.
One of which is that, I don't see the reasons in carving up a MAF an
expecting it to read right.
Running around, vs running correctly has always been an issue with me.
Ya, it's easy to take a we got it running a quit attitude, but I just get
tangled up in the correct / best possible end of things.
bruce
>
> Thanks,
> Jason Norris
> ----- Original Message -----
> From: <timsiford at hushmail.com>
> To: <gmecm at diy-efi.org>
> Sent: Thursday, November 09, 2000 9:14 AM
> Subject: J N's MiniRam backfire
>
>
> > Jason sent me an XLS spreadsheet with data from a scantool that shows a
> > backfire happening when he blips the throttle.  Car = 1987 Vette w/
> MiniRam.
> >  Its pretty interesting.  (Jason, I am posting here because I can't find
> > your e-mail, thirdgen appears to be down, and I also want to share this
> > info with others here).
> >
> > The data clearly shows Jason 'blipping' the throttle from off idle.
There
> > are 4 data points on the throttle blip and you can clearly see the O2
> volts
> > going from the switching behavior at idle (TPS=0.53V) to 0mV on a
Throttle
> > blip.  The data is below.  This appears to be a fueling issue
(expecially
> > when viewing the SA in relation to the throttle blip and LV8).  Its
> undetermined
> > as to whether or not it is a PROM fueling issue or a mechanical fueling
> > issue.  What do you guys think?
> >
> > RPMs,TPS, O2, AFR, Knock, SA, LV8
> > 875, 0.530, 836, 14.7, 0, 25.4, 57
> > 875, 1.630, 712, 11.7, 0,13.8, 189
> > 875, 3.310, 292, 11.7, 0,15.9, 177
> > 1300, 2.94, 0, 11.8, 0, 28.2, 175
> > 1725, 0.90, 13 ,14.7, 0, 45.5, 124
> >
> > Jason - quick question for you.  The MiniRam has ZERO provisions for
EGR.
> >  What PROM are you running?  Are you running $6E code, $32B code?  Is
your
> > PROM image based off an original TPIS image or did you start with the
> stock
> > image as a base?
> >
> > A separate issue is that IMHO, knock -should- be detected and isn't.
> >
> > Tim
>
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