[Diy_efi] Making a fake O2
David Cooley
n5xmt
Thu Jun 2 23:07:46 UTC 2005
Forced open loop, but on TUNED maps, not the factory provided maps without
the benefit of learning trims from an O2??
Or are you comparing apples to oranges again?
> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org
> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Daniel R. Nicoson
> Sent: Wednesday, June 01, 2005 10:08 PM
> To: diy_efi at diy-efi.org
> Subject: RE: [Diy_efi] Making a fake O2
>
> But even that's a rather sweeping statement. You must have
> some particular computer's in mind with a specific experience?
>
> I run my 1994 Mustang computer Open Loop whenever I want, no
> problem. I do have the luxury of changing any maps but with
> stock parts, that computer would run just fine if only forced
> open loop, all other settings left alone.
>
> Dan Nicoson
>
>
> > -----Original Message-----
> > From: diy_efi-bounces at diy-efi.org
> > [mailto:diy_efi-bounces at diy-efi.org]On
> > Behalf Of David Cooley
> > Sent: Wednesday, June 01, 2005 6:18 PM
> > To: diy_efi at diy-efi.org
> > Subject: RE: [Diy_efi] Making a fake O2
> >
> >
> > 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
> >
> > > -----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
> > > >>
> > > >
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