J N's MiniRam backfire

[Bruce Plecan]

(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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