anti-theft chips ?

[timsiford at hushmail.com]

Here's a quick idea....

We've been discussing programming two images onto a double size chip and 
then using a SPDT switch to control which image we are using on thirdgen.org 
(kudos to Tim Burgess!)....
http://www.thirdgen.org/messageforum3/Forum10/HTML/000072.html

Couldn't you just program one image to have a maximum speed of 0mph and 
the other image to function normally?  Seems that easy in theory.

Why even worry about all that anyhow?  You could just wire up a fuel pump 
kill switch using the FP ground.

Tim


At Thu, 5 Oct 2000 12:02:39 -0600, "Programmer" <nwester at eidnet.org> wrote:

>
>I'd think that any type of anti-theft system may be a hodge-podge in 
>an
>emergency...
>I'm not much of a software compiler guy, Dave. Been years since I wrote
>basic <G>...if I wanted to do this in
>a 7747 bin--how'd I do it ?? I know somebody wrote code to
>put a speed limiter in a 7747 bin--and it works great. If it's shown
>to me once...I'm a quick learner. I've seen this before somewhere in 
>my
>internet travels, but can't remember where. Somebody mentioned a
>"secret start" sequence -- maybe it was at the GN site, I dunno. I'm 
>not
>sure
>if this would work but, how'd you write:
>1. If Key on
>2. If TPS + 70% or A/C signal high, or .... PRNDL in R_DL once
>3. Then fuel on ??
>Will the PCM see this as a one time event at start up--it should I guess?
>If you don't have time help--no problem...I'll try to figure something 
>out.
>
>Lyndon.
>
>-----Original Message-----
>From: Dave Zug. <dzug at delanet.com>
>To: gmecm at diy-efi.org <gmecm at diy-efi.org>
>Date: October 5, 2000 7:58 AM
>Subject: Re: anti-theft chips ?
>
>
>>in '97 or so, I patched in code (manually - no compiler) after the 
>checksum
>>to check TPS and compare it with 50%. checksum occurs at key-on and 
>not
>>otherwise (from what I could find - no other calls to the start of 
>the
>code)
>>based on the comparison I would select 1 of 2 spark tables when it 
>came
>time
>>to do the 3d lookup. I suppose if you either put the execution into 
>an
>>endless loop if TPS is not above 50% when the key is turned on. Interrupts
>>may override this though. I made a lengthy post regarding exactly what 
>I
>did
>>maybe a year ago. another consideration is liability of coarse.  If 
>the car
>>must be started in a panic, or BORROWED in an emergency it could gum 
>things
>>up. If an accident occurs it will take high paid experts to testify 
>that
>>there is no way your patch was responsible.
>>
>>DISCLAIMER - DO THIS ONLY ON A TEST BENCH, for fun  ;-)
>>
>>EFI performance made a security version for their GN chips that required 
>a
>>sequence of activities, something like key, neutral, park, TPS, crank.
>>
>>
>>
>>----- Original Message -----
>>From: Programmer <nwester at eidnet.org>
>>To: <gmecm at diy-efi.org>
>>Sent: Thursday, October 05, 2000 2:35 AM
>>Subject: anti-theft chips ?
>>
>>
>>> Anyone ever figure how to write a secret start sequence so
>>> one wouldn't have to shell out big bucks for an anti-theft
>>> system that is so easily bypassed ? My secretarys' husband
>>> had their 89 C1500 SWB stolen right from in front of their house.
>>> They heard the truck start up and drive away--thought it was a
>>> neighbor <g>. That was last week--got the truck back today,
>>> luckily--the idiot that stole it was caught driving drunk...otherwise
>>> they probably wouldn't have had any action on it at all...
>>> Lyndon.
>>>
>>> -----------------------------------------------------------------
>--------
>-
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>>
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