ECM fault?

[Mike Rolica]

How do you figure???  Did you erase the ecm... make it go dumb? Then drive
it for a while?.. the o2 sensor is not used when you first start up or when
you are idling correct?  But does it not influence the idle characteristics
once the ecm is learned?   One thing I have found is run genuine ac/delco
plugs, o2 sensors, tps sensors, iac valves, thermostats, knock sensors, temp
sensors on a gm.  Other parts maybe cheaper but they do not last long or not
at all.  I whent through 3 ngk o2 sensors before I went to an ac delco and
had no problems with it.  Also had 2 cheapo knock sensors that fell aprt in
2 months.  Plugs.. ac/delco rapid fires make the most power out of any
others on a gm (ngk,champ, bosch even the platnum and iridium ones)
Mike Rolica
EXT. 260
 :-)


	-----Original Message-----
	From:	Akselrud, Boris [SMTP:AkselruB at moodys.com]
	Sent:	Tuesday, November 09, 1999 9:29 AM
	To:	'gmecm at efi332.eng.ohio-state.edu'
	Cc:	'Programmer'
	Subject:	RE: ECM fault?

	O2 output does seem slow when you scope it. We did replace it, but I
am not
	sure if it was genuine GM.
	Also I would imagine that right after the replacement while the
sensor was
	brand new we should have felt at least some change in the idle
character,
	but there was no change.
	That's why I am beginning to think that ECM program is causing it by
	reacting slowly or over/under compensating the sensor input. Do you
think
	that it is possible? Of caurse if that's the case, I'll be stuck
trying to
	reprogram it.

	Thanks very much for your opinion.

	-----Original Message-----
	From: Programmer [mailto:nwester at eidnet.org]
	Sent: Monday, November 08, 1999 1:31 PM
	To: gmecm at efi332.eng.ohio-state.edu
	Subject: Re: ECM fault?


	A slow rolling idle can be caused by an O2 that doesn't react fast
anymore
	or has become "poisoned". Have you replaced the O2 with a GM one
??--stay
	away from the generic O2 sensors. Remember--in "closed" loop, the O2
sensor
	is directly responsible for fuel control. The PCM just responds to
what the
	O2 sends--a biased lean O2 will also command a PCM "rich"--as well
as a
	biased rich O2 will command a lean condition overall.

	Lyndon
	-----Original Message-----
	From: Akselrud, Boris <AkselruB at moodys.com>
	To: gmecm at efi332.eng.ohio-state.edu
<gmecm at efi332.eng.ohio-state.edu>
	Date: November 8, 1999 10:11 AM
	Subject: ECM fault?


	>Unfortunately no one answered my first post regarding what I think
is ECM
	>related problem in 5.7 TBI in my 1993 Cadillac Fleetwood.
	>The problem is erratic or I would say unstable idle. Looks like ECM
is
	>leaning the mixture (don't know for sure) causing idle to go below
	>comfortable level for 2..3 seconds followed by 2..3 seconds of
smooth
	>operation.
	>I've gone trough repeated sensors and parameters check on the
engine during
	>the last two years. I am confident that all the sensors working
within spec
	>and I scoped the output from all of them. Mechanical condition of
the
	engine
	>is also good - no noices or knocks, compression tests like new,
ignition
	>system checked repeatedly and spark plugs replaced, no vaacum
leaks.
	Another
	>words the mechanical condition is not at fault. However the output
of O2
	>sensor at idle is somewhat slow with a period of 2 seconds. I don't
know if
	>this is normal for that engine.
	>Could anyone tell me if you have experienced similar behavior of
the engine
	>at idle and if you got it corrected. Can it be ECM induced?
	>Please, share with me what you can, I have exausted all other
sources.
	>