VSS- Part 1 solved

[Bruce Plecan]

-----Original Message-----
From: mrvette <mrvette at bellsouth.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Thursday, October 01, 1998 10:09 AM
Subject: Re: VSS- Part 1 solved


>Feeding the 2k pulse nto the 4k pulse input should work fine,  as I have
driven

If you feed the pulsed 12v into it it just ignores it...........
The 4000ppm is a A/C type signal !........
IF you want to feed it the 2000ppm signal put a 472 cap inline, so
it at least sees the 2000ppm signal.
Bruce
>extensively the 730 'puter without the VSS hooked up at all, for about 6
>months....then I bought that expensive adapter thingy to hook up....only
thing I
>noticed was that the idle speed upon sitting at a light settled down to
~700
>rpm's and stopped that incessant pulsing up and down....that is the oly
reason I
>added the VSS....that idle speed variation drove me crazy.....I think the
2k
>pulse rate should be enuff to tell the computer that you are stopped
>still.....after all the signal is mostly useless otherwise, afterall you
cold be
>in any gear (stickshift) or have any final drive ratio....so just what the
>computer would use with a VSS signal in a running/driving mode I don't
know....
>seems to be a useless input considering the other more important larger
>variables,  load, rpm's.  etc.....just when it's standing still....it needs
to
>know that to set idle speed......GENE
>
>Mike Hoenes wrote:
>>
>> sorry to flog this horse again, but most of the contributors here are
about
>> two feet over my head regarding electronics.
>> anyhow - just so i'm clear on this....
>> does this software change mean i can run a DC 2000ppm VSS signal into my
91
>> TPI 730, and this will replace the normal AC 4000ppm VSS signal the 730
>> expects?
>> i dont have an electronic speedo so i dont care about feeds to the
>> speedometer.
>>
>> thanks for indulging me.
>>  ----------
>> From: Bruce Plecan
>> To: diy_efi at efi332.eng.ohio-state.edu
>> Subject: VSS-  Part 1 solved
>> Date: Tuesday, September 29, 1998 11:52PM
>>
>> OK, this just in and verified.  If you are running a 1227730 ecm,
>> from a 90-92 TPI that uses prom aujp, and you want to run a 2000ppm
speedo
>> input do the following,
>>
>> Change prom address 0018 from D8  to 98
>> Then use C-6 as the speedo input.
>>
>> As run on my bench in side beside testing they were +/- 1 mph..
>> Speed was set, and the the diacom reset and run on the other
>> ecm to compare mph's.  747 to 730.
>> Cheers
>> Bruce         Grumpy lost a dime on this bet, and has been in a
>>                     fit over it (course that's a days wages here).
>
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