Swayze wrote:
>
> suggest you check LM331 at National (an-c.pdf?)
Not sure that's the direction I need to go - a V/F device? Hmm....
More info. I didn't admit this in the original post - since this is the
*GM* ECM list, but my friend's truck is a Ford. If you hardcore GMECM
types will allow me a little deviance, here's a little more detail on
what he has done...
It started as a MAP-based 1987 (I think, could be an '88) 2.9L V6 Ford
Ranger. He added a larger stock Mustang throttle body, purchased a
California-only version of the Ranger ECM which was MAF based, and added
a stock Mustang MAF sensor (stock Mustang parts can be had for about the
cost of shipping these days). He's had to fab a few plates from aluminum
to get stuff to bolt up, but it's actually working very well, and with
his ported intake and exhaust work he's picked up about 1/2 second in
the 1/4 mile so far. He also has "bragging rights" that his Ranger is
MAF based, rather than MAP.
However, he's got just this one little "deal" with the MAF sensor
reading too low at idle. I'm wondering, though, if he could simply
insert some sort of restrictor plate in the main body of the MAF meter
to force more air through the bypass measuring area of the Ford MAF
sensor. That way we wouldn't have to have any electrical tomfoolery.
(Since the Ford MAF sensor has a main artery, and a small "bypass" area
where the actual metering occurs.)
He has a book on Ford fuel injection that has him measure the input
impedance of the MAF sensor input to the ECM, and it does measure low
(the book says "should measure over 10k ohm", but it actually measures
about 3.33k ohm). This does concern me (umm, that would cause voltage to
read low!), so I might look at the ECM, or recommend he swap it for
another one.
Sorry for the non-GM content, but I think it's a pretty interesting
project nonetheless. Thanks for the ideas so far!
-Andrew
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