J N's MiniRam backfire

[JN]

The recording is a neutral blip.  It also does it in gear.  Smoothly
increasing the throttle is fine.  It's when you shift and then hit the next
gear kinda hard you feel a dead shot and sometimes a backfire.  Another
interesting note is that the zero O2 reading after hitting the gas was also
recorded (not noticed) when I had the Super Ram on.  There are alot of
Minirammed MAF cars out there running fine.  Maybe someday I'll go to a MAP
(which by the way, TPIS claims are a real bear with a miniram) but not until
I learn this MAF system better.

Jason
----- Original Message -----
From: "Bruce Plecan" <nacelp at bright.net>
To: <gmecm at diy-efi.org>
Sent: Thursday, November 09, 2000 10:28 AM
Subject: Re: J N's MiniRam backfire


>
>
> (reference a modified engine)
> Well, might be time for a 730, and MAP.
> I'm kinda assuming that is a *neutral* blip of the pedal.
> On a MAF system if you want any real response in neutral you just won't
find
> it.  They aren't made to operate that way, and the calibration is going to
> take a really serious amount of work to cure it **correctly**.   The MAF
> demands a min certain lenght to get the air *straightened* out enough so
> that the MAF sees it correctly, with the change in runners and plenum, he
> now has a very different system.  The AE, and IAC stuff will all have to
be
> retuned.   EFI like anything else must be balanced, each and every
> component.
> Being able to blip the gas isn't part of the EPA cycle and I doubt any
> meaning ful time is devoted to it.  There just isn't a MAP AE correction,
> and the TPS AE of the MAF just would have a hard time (as in really
> couldn't) cover that same hole.
> Even a MAP system for a neutral blip aint the greatest in the wold when
> comparing to say a carb..  It's the ingear stuff that matters,
> Bruce
>
>
>
>
>
> > 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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