[Diy_efi] Making a fake O2
Mike
niche
Fri Jun 3 05:26:15 UTC 2005
At 07:09 AM 3/06/05, you wrote:
>That is called "Limp" mode in a GM computer.
>The original poster was talking about faking an O2 signal, so there would be
>no forced 5% enrichment, only the BARE raw fuel maps in the factory cal.
>Again, learn to read.
>
>Fucking morons
I think you need some anger management.
I was responding only to *your* comment below, not having to recall the whole
thread, you said we should read your post and kindly pasted it for reference so
there would be no misunderstanding, here is your comment and my response
was relevant to it:-
> >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
Now - you are saying I should also have read some other post and mostly
ignored your re-interation above ?
What gives ?
Mike
>
>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org
>> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Mike
>> Sent: Thursday, June 02, 2005 1:30 AM
>> To: diy_efi at diy-efi.org
>> Subject: RE: [Diy_efi] Making a fake O2
>>
>> 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.
>> >> >>
>> >> >> _______________________________________________
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>> >> >> Diy_efi at diy-efi.org
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>> >> >>
>> >> >
>> >> > _______________________________________________
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>> >> >
>> >>
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>> >>
>> >
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>>
>> Regards from
>>
>>
>> Mike Massen
>> Perth, Western Australia
>> VL Commodore Fuse Rail that wont warp or melt !
>> http://niche.iinet.net.au
>>
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>
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Regards from
Mike Massen
Perth, Western Australia
VL Commodore Fuse Rail that wont warp or melt !
http://niche.iinet.net.au
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