Dead driver on '165?

[Thomas Matthews]

If you think the "engine" fails to "start" because of the MAF, unplug the
MAF, and  the ECM will go to limp home mode- then look and see if you have
injector firing... then you can replace the MAF with a 0-5 volt power
supply, and fake having airflow on the bench...
Tom
----- Original Message -----
From: rr <RRauscher at nni.com>
To: <gmecm at efi332.eng.ohio-state.edu>
Sent: Tuesday, October 26, 1999 11:23 PM
Subject: Re: Dead driver on '165?


> I got a weird feeling, try a small fan blowing into the maf. Maybe
> without airflow, it won't kick the fuel on?
>
> BobR.
>
> Bob Valentine wrote:
>
> > Here's what I've got, and I'm suspecting either the injector drivers or
> > something else is fried in this ECM.  Note that I never actually ran it
in
> > a car.  I've checked most of the sources for a schematic of the '165 and
> > haven't found any.  Is there one?  Again, this is '165 / ABYA (88 350
Camaro)
> >
> > My "test bench" consists of the ECM, all non-emissions related sensors
> > (except for VSS) and all 8 injectors (note I'm using Ford injectors
which
> > tested ok on my 555 injector cleaner/tester).   I have the dist. hooked
to
> > a variable speed motor, I've been "cranking" the motor at about 100-300
rpm
> > (dist speed) which corrolates to about 200-600 crank rpm.    MAF is
hooked
> > up, park/neutral line is tied +12, FP is also hooked up.  TPS is set a
.5v
> >
> > On "cranking" the FP comes on and stays on until "cranking" stops.   IAC
> > motor can be heard exercising slightly.   The injectors never fire, not
> > even once.  Swapped in a noid light, it doesn't come on either.   I have
a
> > 555 VATS eliminator tied to pin B6, I've tried frequencies ranging from
> > about 20 to 40 hz (as determined by my o-scope).   With or without the
VATS
> > makes no difference in the operation below.
> >
> > Everything seems fine except for the fact that the injectors don't fire.
> > The check-engine light (no scanner / aldl reader yet...) turns off
> > momemtarily while cranking, then comes back on.    ECM is setting a code
> > 34;  low MAF reading. This is to be expected since there's no
airflow....
> > ;^>  I've checked for power at all sensors and the MAF - it's there and
good.
> >
> > The only other thing is that the main heatsink in the ECM gets fairly
warm
> > after about 10-15 minutes of power applied.   Is this normal?
> >
> > So are the injector drivers bad, or is there still something with the
VATS?
> >
> > --> Bob Valentine
> > --> bob at tecmark.com
>
>