[Diy_efi] Making a fake O2
Mike
niche
Thu Jun 2 05:29:38 UTC 2005
At 06:17 AM 2/06/05, you wrote:
>I never said that ANY open loop maps would destroy an engine...
>My comment was that a computer DESIGNED FOR CLOSED LOOP WITH AN O2 SENSOR if
>run in open loop only with the O2 disabled will cause damage.
>Geez people, learn to READ
Having looked closely at the Hitachi/Bosch ECU for the NIssan RB30E
and RB30ET for some 10 years or so - I really doubt the efficacy of
your wild generalisation. This ECU is designed specifically for use with
a classic O2 sensor and has many modes that allow it to operate
reliably without input from some sensors, in that respect:-
If the O2 sensor is faulty or missing the ECU runs open loop *plus* makes
the mixture about 5% richer overall. ie It still uses the primary inputs of AFM and
engine speed to provide open loop fueling but cannot close the loop, therefore
it must be open loop - yes ?
How can this cause damage when it averages 5% or so enrichment ?
Provide some earnest rationalisation to support your generalisation please ?
Mike
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org
>> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Marcello A. Belloli
>> Sent: Tuesday, May 31, 2005 11:28 PM
>> To: diy_efi at diy-efi.org
>> Subject: RE: [Diy_efi] Making a fake O2
>>
>> Dan,
>> Yes, that is exactly where I am. The stock computers
>> mapping is in no way set up for the engine that is now
>> connected to it. Everything you said is right on. We have a
>> mismatch. The stock ecm and its mapping isn't going to work.
>> I have kept reading hoping the bickering would stop. I
>> agree with both sides of the debate. GM computers are
>> terrible when their O2s fail. And run so rich I'm couldn't
>> understand why anyone would drive it. Now the ECM I'm
>> running in my Landcruiser is a GM with TBI setup out of 1989
>> C series 5.7l GM truck. And it will actually use data
>> gathered during closed loop to effect WOT. And it can do damage.
>> Now, the Honda/Acura setup we're working on right now will
>> run so rich with the o2 disconnected it will barely idle.
>> Now these are two cars. I have also seen setups where you
>> could remove half the sensors on the car, and the computer
>> will keep it running like nothing ever changed. And it won't
>> set a light. Dodge Caravan OBDII. And the emissions will be
>> perfect. I believe it is smart enough to use other data to
>> make a good guess (kinda like
>> Speed-density) at what the sensor should be reading. You
>> would be hard pressed to get one of these engines to hurt
>> itself. And if there was misfire that could cause damage it
>> will kill cylinders to wake the driver up (Thats if they
>> don't see the flashing MIL lamp) and protect the engine.
>> There are many computers out there, and many different
>> approaches used. Now I have never personally seen a motor go
>> boom because of a bad o2 sensor, but I have seen a lot of
>> damage done. The o2 goes bad. The cat plugs up, the exhuast
>> is restricted, and the temps at the engine exhuast go
>> steadily upward. Exhuast valves damaged, seals damaged,
>> exhuast manifolds damaged, cylinder heads damaged. etc,..
>> I believe that it all depends on the computer you are using.
>> There are computers that go both ways.... I also don't see
>> the problem with an open loop car. The Carburetor analogy is
>> a good one. I've run vehicles 100,000 of miles with a
>> carburetor without any problem.
>> And I can think of one setup or two aftermarket setups that don't use
>> o2 sensors unless you add them. Both Eldebrock, and Holley
>> have aftermarket EFI setups that don't intially use an O2. I
>> think Accel has one two. And these things have been used in
>> many cars, and trucks without any problems.
>> And this all started with a simple question about faking
>> out the o2...
>>
>> Marcello
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> > I've been watching this thread over the last few days. People are
>> > debating the safety of the stock maps with 02 faulty but no one has
>> > mentioned that the engine in question is no longer stock. Marcello
>> > mentioned that his friend "only made a few changes"
>> (eye-roll) meaning
>> > to me that probably the friend put together a parts combination far
>> > from stock. Most likely higher compression and a more
>> aggressive cam.
>> > Those two possibilities alone probably would make the stock maps
>> > irrelevant or at least "not safe".
>> > Considering how much $$ most people typically throw at a motor when
>> > they "make a few changes" I would proceed slowly and work
>> to develop new maps.
>> > I
>> > think Marcello realizes this and hopes his friend will keep
>> his foot
>> > out of it until he gets home to work at the problem logically.
>> >
>> > My experience is with Ford EEC's. I know when I "made a
>> few changes"
>> > the EEC was totally confused because my parts changes had taken the
>> > range of operation well beyond the stock limits of compensation.
>> >
>> > Good discussion.
>> >
>> > Dan Nicoson
>> >
>> >
>> >> -----Original Message-----
>> >> From: diy_efi-bounces at diy-efi.org
>> >> [mailto:diy_efi-bounces at diy-efi.org]On
>> >> Behalf Of Steve Ravet
>> >> Sent: Tuesday, May 31, 2005 12:36 PM
>> >> To: diy_efi at diy-efi.org
>> >> Subject: RE: [Diy_efi] Making a fake O2
>> >>
>> >>
>> >> I was going to refer to the EFI testbench that Bruce built. My
>> >> recollection is that he used a 555 type circuit to generate an O2
>> >> signal. There's not really any mention of it in the
>> article, but I'm
>> >> sure the details are in the archive. I think for some
>> computers this
>> >> worked OK, for others that expected to see more
>> correlation between
>> >> pulsewidth and O2, it didn't. Anyway, go to the gmecm page,
>> >> projects, then ECM testbench for the ascii version of the
>> article.
>> >> The MS word version is probably gone for good.
>> >>
>> >> --steve
>> >>
>> >>
>> >> ________________________________
>> >>
>> >> From: diy_efi-bounces at diy-efi.org
>> >> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Bret Levandowski
>> >> Sent: Sunday, May 29, 2005 11:16 AM
>> >> To: diy_efi at diy-efi.org
>> >> Subject: Re: [Diy_efi] Making a fake O2
>> >>
>> >>
>> >> Actually, it is not 'impossible to fool an ECU with a
>> constant or
>> >> switching voltage source'. There are two companies I know
>> of (in the
>> >> states) that have developed a plug-in replacement for the
>> O2 sensor
>> >> on numerous vehicles (mostly OBD II) that generates a
>> 'proper' signal.
>> >> These are used in instances where inj size was increased
>> or a turbo
>> >> or screw-charger was installed. Some also did require a
>> flash of the ecu.
>> >>
>> >> _______________________________________________
>> >> Diy_efi mailing list
>> >> Diy_efi at diy-efi.org
>> >> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>> >>
>> >
>> > _______________________________________________
>> > Diy_efi mailing list
>> > Diy_efi at diy-efi.org
>> > http://lists.diy-efi.org/mailman/listinfo/diy_efi
>> >
>>
>> _______________________________________________
>> Diy_efi mailing list
>> Diy_efi at diy-efi.org
>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>
>
>_______________________________________________
>Diy_efi mailing list
>Diy_efi at diy-efi.org
>http://lists.diy-efi.org/mailman/listinfo/diy_efi
Regards from
Mike Massen
Perth, Western Australia
VL Commodore Fuse Rail that wont warp or melt !
http://niche.iinet.net.au
More information about the Diy_efi
mailing list