[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: reprogramming MAF xfer function in '165 ECM



Hi Nick:  Is your friend running an automatic trans?  If he is he should
convert to 89 code and eliminate the cold start injector.  89 code seems to
run better too.
The stock maf flows 529 cfm at 28" of water.
With the screens out it flows 711 cfm.
With the screens out and the heat sinks removed if flows 750 cfm.
These figures are plagiarized straight from TPIS's insider hints.

But I did flow my maf on a superflow 600 and it flowed 600 cfm at 11" which
if you use the Superflow chart = 796.37 cfm.  ( spent some time on that maf
smoothing things out too.

What I have done is with the ported maf it throws off the calibration.  I
don't have it all worked out yet, but I am still working on it.  I max the
maf at 255 grams/sec at about 4700 rpms with my 355 cu in.
So what I have done is added fuel on the PE vs RPM section of the prom and
also told the ecm that I am using 21 lb injectors.  I am considering playing
with the maf calibration and/or the LV8 scaling factor and or the scaler for
the maf table.

But without rescaling anything it runs pretty good.  Basically becomes alpha
N  after the maf sensor pegs.

Mark
-----Original Message-----
From: NickG <nikog@mediaone.net>
To: GM ECM List <gmecm@lists.diy-efi.org>
Date: Sunday, February 27, 2000 8:36 PM
Subject: reprogramming MAF xfer function in '165 ECM


>I'm helping a friend tune his '87 vette. He's got a 383cu. in. engine in it
>with all the goodies. One of the mods is a modified stock mass air to allow
>more airflow (the engine is starved for air).
>
>I wanted to have the meter measured so I could have its transfer function
to
>put into the eprom. I then realized that the ECM only uses an 8 bit value
to
>indicate the mass air flow, and that 255d represents 255g/sec of airflow.
>The meter we have now is probably capable of flowing more air than that, so
>I can't program the correct transfer function into the eprom (not enough
>bits).
>
>Does anybody have any ideas as to how to set this up properly?
>
>Thanks,
>Nick
>
>
>---------------------------------------------------------------------------
-
>To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
>in the body of a message (not the subject) to majordomo@lists.diy-efi.org
>

----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org