Obd Ii Vpw
10-27-2004, 11:45 AM
#1
Obd Ii Vpw Having dropped an LS1 in my RX7, I am now interested in building my own OBD II interface. Have found a lot of info but I need to know the nominal time required between VPM pulses. Anyone have that info or can direct me to a web page that might?
10-27-2004, 11:57 AM
#2
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There is some of that kind of detail in the older part
of the hptuners.com site (used to be a PCM hacking
BBS before they "went commercial") and there are
a few other similar boards / sites out there with folks
cobbling up low level interfaces etc. But there are
also at least three commercial scan tools and two
released programming tools (plus one in beta test
and nominally releasing in November) that support
scanning to varying degrees (LS1-Edit has a semi-
functional beta version scanner out and HPTuners
has scanning / logging as a solid part of their suite).
Places like obdii.com, the diy-efi list, those kind of
places will have a lot of low-level VPW detail.
So if you're building it for fun, search for the do-it-
yourself pages; if you're building it so you can tune,
I'd just cut to the chase.
of the hptuners.com site (used to be a PCM hacking
BBS before they "went commercial") and there are
a few other similar boards / sites out there with folks
cobbling up low level interfaces etc. But there are
also at least three commercial scan tools and two
released programming tools (plus one in beta test
and nominally releasing in November) that support
scanning to varying degrees (LS1-Edit has a semi-
functional beta version scanner out and HPTuners
has scanning / logging as a solid part of their suite).
Places like obdii.com, the diy-efi list, those kind of
places will have a lot of low-level VPW detail.
So if you're building it for fun, search for the do-it-
yourself pages; if you're building it so you can tune,
I'd just cut to the chase.
10-27-2004, 05:51 PM
#3
I've looked into this, my suggestion is forget about doing your own VPW interface and get one of the chips out there that does it for you with simpler serial interface to the chip. Or, if you want to go lower level hardware design, use a VPW transceiver chip (like MC33390) which handles the timing for you.
