Re: P&H Injector Interface

["nacelp" <nacelp@bright.net>]

> >Pg 182 shoes the late truck ecm connectors (Drk Rd-Drk Blue)
> >12089660 Terminals
> OK, if you're saying the ecm connectors are MicroPack connectors, then
> the terminal part no. you have above (12089660) I don't see in the
> catalog (btw, where'd you get that #?).

I'd have to shot myself if I told ya,
Note to others, pays to save some parts numbers I throw out.

 The female MP terminals are on
> pg. 172, along with all the currently available housings. Most of the
> other numbers you quoted aren't in the catalog either, nor in the
> cross-reference. That's no biggie if it's just the color of the plastic
> that's involved. They often made color specials for OEM usage. But the
> fact that the terminal numbers don't correspond has me still a tad
> worried. Have a look at pg. 172, and see if those terminals are indeed
> the females we're seeking, and you're using.

*My*, numbers are the older numbers used when 730s (and it's "clones") were
in production.

> >What I thought was 727 terminals were wrong, I can't find them anywhere
in
> >this catalog
> Hmmm, wonder if on those they used someone other than Packard as
> supplier? Gawd, why would they DO that?

I don't think they can out side source them.  UAW is really picky about
these matters.  Just so long outta production is my guess.  John Flagg had
dais if e-mailed photos he know he could match up the 727 connectors

> OK, Segue back to another erstwhile issue:

You realise how much research your skimmin off here <g>...

> ...if these GM ECM terminals we've been discussing are indeed MicroPack
> connectors (which I trust they are), be aware that the nominal rated
> current per circuit on the MPs is 5A. Hence my concern about peak
> currents when driving 4 P&H injectors thru them. When driving one TBI
> (1.2ohm 2mH) injector on such a circuit, this is just within parameters
> (it might not look like the math is right, but the 1.2ohm injectors are
> sposed to have a nominal current-limited peak of around 4.5A, and a hold
> current around 1A: remember you have to consider the inductance as well
> as the resistance), and would be equivalent to driving two (2) TPI
> (2.4ohm) injectors, but I think driving four (4) TPI injectors puts you
> over the top. [With sat injectors (12-16ohm), you can see how you can
> drive considerably more of those injectors together thru one such pin].

Well, hmm, I just finished some stuff where we ran some (3)  2.4s  static,
and the only down side was the injectors getting hot.
Not very often are you running any of this stuff at 100% DC. Matter of fact
80 seems about oem max, from what little testing I've done.   At light
cruise you at like 3-4 msec at 2000 rpm, gotta be lots of time for things to
cool, I'd think.

> Now, mind you, you CAN "get away with" that, all that happens is the
> terminals get warmer, and the contact resistance goes up, and the
> low-side load floats up a bit. But in the long run, it's considered bad
> practice to exceed these ratings, because outside it's design limits the
> terminal is corroding from the heat, stressing from the thermal cycle,
> and the injector solenoid isn't pulling in quite as firmly as it would
> have normally, due to the increased resistance.

Heck ya got a sensing resistor in there anyway, what's a couple .1s ohms
gonna change opening/closing rate.

All not-so-good
> downsides. This is all on a continuum tho; just be aware you're skating
> on thinner ice when you hang out on the hairy edge like this. The curves
> on all this bad stuff mentioned above, go up very rapidly outside the
> design region. That's how they decided what IS the design region for the
> connector pin. :)
> Makes we wonder more about the wisdom of retrofitting new higher-power
> drivers directly into the ECM box. All that extra drive current has to
> go out those wee pins. Better to take an injector "signal" from the box,
> and let the bigger external drivers handle the extra load with
> better/bigger contacts (not to mention bigger ground returns) on their
> own side. That'd be my take. Guess I'm getting leery of this "secondary
> ECM connector idea", especially if we're still talking about driving 4
> P&H injectors thru one pin. Hey, call me paranoid, call me
> overly-cautious, but don't call me if months down the road, during some
> critical race, your connectors start to smell and get intermittent on
> ya. In fact, driving 4 (2.4ohm) P&H injectors thru one of these pins is
> far enough over the edge for me that I think this is where I get off the
> train.

Build one, ship her over, and I'll run it thru a ringer so tight I'll stand
behind it if its passes my test.  We gotz lots of batteries waiting to give
there all in the search for truth here.  Or pencil me out what ya want if
other then the pdf ya offered of the cherry drivers
Grumpy

> I think bigger connection pins are in order for these conversions. Just
> me dos centavos, amigos. Back to the intrusive wire splice. Sorry Eric.
> Crumbs, why do I have to always play the part of the Ogre? Whimper.
> Gar


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