Re: added baro sensor to 730

["John S. Gwynne" <jsg@jsgpc.mrcday.com>]

| Seems like a lot of added work.  Why not just read the MAP for baro at
| start up and then defeat the engine running baro re-calc code?  That
| code is probably what is screwing your baro up.
| 
| Scot Sealander

Hi Scot,

It wasn't that much work... any how... as I'm sure you know that the
baro value is stored in NVRAM at 0x002e. with a quick start from fuel
still in the engine (you can see this by pulling the injector fuses
before starting), the engine can pull enough vacuum by the first read
to offset the value by 5-10kPa... based upon data collected, slow
starts would not be a problem. The factory code expects this too. The
initial condition for the first baro read is that the read value must
be greater than that stored or no update.  Excluding this you still
have a CPU restart while driving (I suppose your code senses this and
just doesn't update?), and change in altitude while driving (I've
heard of situations of cars running rough while climbing a mountain
before being floored or restarted... anyone have an experience with
that?). It just makes more sense to me to put the second sensor in
since I had one laying on the work bench and the ECM had a pin just
waiting for it. The alternative software solution I considered was to
be more limiting over the rpm/TPS range. For the level of effort, it
seemed to be the best fix.

john gwynne
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