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Re: added baro sensor to 730



----- Original Message -----
From: John S. Gwynne <jsg@jsgpc.mrcday.com>
To: <gmecm@diy-efi.org>
Sent: Tuesday, March 21, 2000 7:52 PM
Subject: Re: added baro sensor to 730


>
> | 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?).

Yep, even in just long distance driving.   In the *Smokie/Blue Ridge
Mountains*, would have to clear the 747s throat a couple times, during an
afternoon, cruise.  Some occasions yes was probably also due to lack of IAT.
Grumpy


 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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