P&H Injector Interface

[Garfield Willis]

On Mon, 22 May 2000 14:45:03 -0400, "nacelp" <nacelp at bright.net> wrote:

>As far as gm goes, I don't know of a popular 4 cyl gm SEFI that folks are
>likely to hop up.  Now batch fires are another issue.
>...
>Bashful
>    Holding the fort, since the last incident

Thanks Bash. Say, do you know if Grumpy is gonna be carrying his laptop
with him?

>> If a module was made that covered
>> just 6 & 8-cyl cases, would that cover just about everybody in the SEFI
>> camp? Lastly, would anyone mind paying the additional small incremental
>> cost to an 8-cyl interface module, even if they only needed a 6 at the
>> time (say for the sake of conversation the *difference* was less than
>> $40)? Would someone rather have the chance to use the same interface
>> module later on an 8 they might run across, and be willing to pay for an
>> 8, especially if only an 8-injector module was made? Or would that piss
>> the 6-cyl guys off?

Anyone else wanna take a shot at this question? Remember, this only has
to do with the Sequential P&H Interface module issue. Come on, there's
gotta be at least one guy contemplating P&Hs in a sequential ECM onlist
that has an opinion. Then again, maybe not.

BTW, here's the present thot on the Batch side of things: basically, we
wanna drive two wires, each with 2, 3, or 4 P&H TPIs. The issue is that
the peak current and hold current levels for each combo are different.
I'd like to avoid a bunch of different models, so the thot is just to
make the internal drivers big enough for the worst case, and then you
*switch-select* how many P&Hs you're intending the interface should
drive. This means a bit of overkill for the lower end of the driving
requirements (if you only wanted to drive 2 or 3 per wire), but I don't
think the cost differential is worth designing several different models.

So, what I'm thinking at this point is one switch-selectable interface
module for Batch, which I think/hope covers all the GM cases, and one
SEFI interface module which contains enough drivers for 8 separate P&H
injectors (of the 2.4ohm 4mH variety). If you need only 6, well I guess
you have a couple spares. :)

In the case of the Batch module, I think a hard break into the harness
wire near the ECM is the only acceptable/reliable waytogo. Bruce's
suggestion to provide all the connectors, etc. and allow fallback to the
original wiring, would be the plan. In the case of the Sequential, if
it's possible to manage a simple pin-swap with a cheap pin extraction
tool and connectors supplied, that would be the plan. Either way would
be completely reversable, electrically speaking.

If ya wanna influence this, ya gotta gimme yer feedback.

Gar


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