[Diy_efi] Making a fake O2

Tue May 31 10:35:13 UTC 2005

David, i am no engineer, but in my limited experience with EFI's, damaging an engine just by use or misuse of a O2 sensor can be achieved only by dropping the sensor in the inlet manifold while the engine is running.

those who design EFI's and those who integrate them on engines know their business. O2 sensors can only correct fueling by a few % and maps are usually conservatively designed, so that any sensor failure won't damage the engine. i have a high performance turbocharged italian sportcar, which would be the perfect candidate for your theory. and i can assure you, there is NO way of damaging the engine by manipulating the O2 signal.

> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org 
> [mailto:diy_efi-bounces at diy-efi.org]On
> Behalf Of David Cooley
> Sent: Dienstag, 31. Mai 2005 03:53
> To: diy_efi at diy-efi.org
> Subject: RE: [Diy_efi] Making a fake O2
> 
> 
> No, Adam is saying that the factory base fuel maps will NEVER 
> cause problems
> if a vehicls is run in open loop only with NO O2 corrections.
> I have seen melted pistons in engines that had bad O2 sensors 
> and the owners
> "fix" was to remove the service engine soon lamp...
> According to Adam, this never happens and he is actually 
> telling someone
> that wants to run open loop only that it will cause no 
> damage... He must
> have a good attorney for being able to give that advice...
>  
> 
> > -----Original Message-----
> > From: diy_efi-bounces at diy-efi.org 
> > [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Mike
> > Sent: Monday, May 30, 2005 1:28 AM
> > To: diy_efi at diy-efi.org
> > Subject: RE: [Diy_efi] Making a fake O2
> > 
> > At 11:53 AM 30/05/05, you wrote:
> > >Ah, so your experience is a global observation on everything...
> > 
> > David, this is not *everything*, this is a specific technical 
> > list where people are generally technical and that usually 
> > means they have a background in high school physics, 
> > chemistry and maths and move on to higher studies such as 
> > engineering, masters or even a PhD...
> > 
> > The side effect of any technical discipline is the huge 
> > benefit this allows to rationalise most phenomena in 
> > combination with industrial and commercial complexity as they 
> > all come back to scaffolding upon the fundamentals of physics 
> > and chemistry...
> > 
> > Engines are not that complex really, there are combinatorial 
> > issues which are sometimes way beyond most people who have 
> > never had the opportunity to get the basic groundwork of 
> > physics and chemistry sorted out at an early point in their 
> > development. Plus it helps to occasionally suspend 
> > personality so one can launch into abstract notions with less 
> > limitation.
> > 
> > There's also nothing wrong with enjoying a good hard nosed 
> > technical speculation from time to time either ;-)
> > 
> > >You must be a legend in your own mind! 
> > 
> > Do I hear knee jerk reaction from a battered ego...
> > 
> > <chuckle>
> > 
> > Mike
> > 
> > 
> > 
> > 
> > 
> > >> -----Original Message-----
> > >> From: diy_efi-bounces at diy-efi.org
> > >> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Adam Wade
> > >> Sent: Sunday, May 29, 2005 10:11 PM
> > >> To: diy_efi at diy-efi.org
> > >> Subject: RE: [Diy_efi] Making a fake O2
> > >> 
> > >> --- David Cooley <n5xmt at bellsouth.net> wrote:
> > >> 
> > >> > If your injectors are starting to have reduced flow due to
> > >> deposits,
> > >> > low fuel pressure etc, the stock maps are NOT going to be safe.
> > >> 
> > >> Most Honda factory turbo motorcycles have never had their 
> > injectors 
> > >> cleaned, and many are operating with fairly clogged fuel 
> filters.  
> > >> I've never seen nor heard of any engine problem on ANY 
> > Honda turbo, 
> > >> for ANY reason.  They run open-loop, and have been in 
> > service since 
> > >> 1982.
> > >> 
> > >> If turbocharged motorcycle engines can handle it, I daresay 
> > >> normally-aspirated applications will be quite safe when 
> > operated in 
> > >> open-loop without BLM, unless the maps themselves are pretty 
> > >> horrible.
> > >> 
> > >> > The O2 sensor is there to correct for changes in
> > >> airflow/fuel flow etc
> > >> > in the engine to keep the A/F where the manufacturer 
> specified...
> > >> 
> > >> No, the O2 sensor is to command a stoichiometric mixture during 
> > >> low-load steady-state operation.  One of the added 
> > benefits that has 
> > >> come with that is the
> > >> (limited) ability for a manufacturer to partially 
> > compensate for age 
> > >> via the use of BLM tables.  Prior to the emissions 
> > requirements that 
> > >> demanded a three-way catalyst and long-life emissions 
> components, 
> > >> there were no oxygen sensors used in fuel injection.
> > >> And if it was really that advantageous, then every fuel-injected 
> > >> motorcycle made in the past 10 years would have an O2 
> > sensor.  You'll 
> > >> note that most of them don't, and the ones that do only 
> > did so when 
> > >> the EMISSIONS requirements were raised to the point where 
> > closed-loop 
> > >> running with a catalyst was necessary.
> > >> 
> > >> > If you take a vehicle that isn't brand new, and run it 
> > in open loop 
> > >> > with no corrections, then yes, the open loop maps MAY 
> > cause damage.
> > >> 
> > >> So all us motorcycle riders who got injected bikes without 
> > O2 sensors 
> > >> can sue the manufacturer for making self-destructing 
> > engines?  Cool!
> > >> 
> > >> Frankly, since both open- and closed-loop running depend 
> > on the same 
> > >> ingition tables, any fuel maps that would "damage"
> > >> an engine when it was older would also be very likely to 
> damage it 
> > >> when new.  Further, think about where best-power fuel 
> > mixture is, in 
> > >> terms of potential engine damage...
> > >> 
> > >> Somehow, I am certain that those creating the fuel maps for 
> > >> automotive OEs are not neary as horribly stupid as you're 
> > saying they 
> > >> are.
> > >> 
> > >> | 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr 550 
> > (Daphne) | "It 
> > >> | was like an emergency ward after a great catastrophe; it  |
> > >> |   didn't matter what race or class the victims belonged to.   |
> > >> |  They were all given the same miracle drug, which was coffee. |
> > >> |   The catastrophe in this case, of course, was that the sun   |
> > >> |     had come up again."                    -Kurt Vonnegut     |
> > >> | M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |
> > >> 
> > >> __________________________________________________
> > >> Do You Yahoo!?
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> > >> http://mail.yahoo.com 
> > _______________________________________________
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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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