Hi Barry

I'm not an expert on ECU's, but have had to find ways to get them to behave
when running engines on a dyno without many of the bits that are fitted in
the vehicle.

If you definitely have no O2 sensors, you would need to rig the inputs (the
second sensor) to indicate a Lambda 1 condition, since otherwise the ECU may
continuously cycle the mixture to try to find the right operating point. I'm
not sure it would be possible to achieve success without at least 1 sensor
(closest to the manifold) since this sensor drives the basic mixture setting
and the second the fine tuning The next problem is that once it finds a
"failure", it may switch into a "basic strategy" mode, which may reduce the
performance significantly. If this is the case you may need to have a
dealer reset the ECU, then fix all the signal level issues before powering
it up again.

The best way to avoid these issues is to look at the signal levels of all
the inputs in the car under normal driving conditions (engine hot,
transmission in drive etc), then simulate these signal conditions at all the
inputs that are not used in your application. You should also check if you
are getting plausible signals from the accessories which you are using
(massflowmeter, crankshaft & camshaft sensors at the very least)

Be aware that full throttle will always result in a rich mixture. If you
back off just slightly from full throttle the mixture will be leaner
without a significant power reduction.

Best of luck
Keith
"Barry Palmer" schrieb im Newsbeitrag
...
Anyone out there work with EFI engines. I have a 4.3L Chevy V-6 that was
removed from a car with its ECU and when operated with a propeller load
does
not want to get above 1500rpm, (should go to 4200rpm) while it hunts up
and
down for the correct mixture ratio. The transmission is removed, if there
are
any sensors on it they are caput. I hate to just blame it on the O2
sensor.

Anyone have any suggestions as to newsgroups in the hot rod area that
work
with the ECU's?

Barry Palmer, for Sevtec (http://members.aol.com/sevtec/sev/skmr.html)