advise or help needed to measure hall output, and spewage

[urq]

... sorry to be so frank Ken, but if you really don't even know how to use
the tools you really should consider yourself in over your head.  Perhaps
the thing for you to do is to find someone in your area who is familiar with
using an oscilloscope and have them work with you.  Perhaps you can work
with the EFI vendor ... seems to me you actually paid money to them for it,
they might want to provide some sort of support!  I haven't really done a
lot of investigation into such systems, but I doubt that many are designed
with the intention of working with the various signals different
manufacturers use.  On EFI332 the project makes use of a particular wheel
with a specific tooth configuration that you bolt onto your engine somewhere
...

The Hall signal is pretty much a "digital" signal ... it is in one state
when the sender is blocked by the shutter and the other when it is not.  The
speed sensor signal looks pretty much like a sine wave ... and the reference
sensor has a very interesting signal which is the result of a single metal
pin flying up and past a coil of wire.  As important as knowing the
individual signals is understanding how they work together ... and this
takes a good bit of work to understand in detail.

Perhaps the best reference I've seen is the Audi IST documents for the urq
... which seem to still be available from Dyment.  Other than the relocation
of the pin in the flywheel the info in the IST applies to the MC as well.
Be advised that even the IST docs aren't going to answer all of your
questions!  One other idea ... see if anyone wants to work with you on this
on the "torsen" list.  Since the bandwidth there is much more reasonable I
can still monitor that list from my e-mail at work ... perhaps I might even
have time to help ...

I would love to be able to help you with you project, and I'll bet there are
others on the list who would like to do likewise ... but really I didn't
even have the time to put this message together ... seeing that now it is
after 7 I really need to get going!

Good luck with your project Ken!  I do hope this note helped!

Steve Buchholz
San Jose, CA (USA)
>
> My efi project is pretty much stalled.  Motor is a MC-1 with
> MAC11B setup/pieces, efi ecu is LinkPlus, car is an '85 4ksq.
>
> I'm waiting for myself to acquire tools and skills to get information
> about the stock ignition system triggers.
>
> This is even for an implementation using the standard, cam-driven
> hall sensor output for the sync signal.  Not with my more
> complicated and even less likely-to-happen idea to create a circuit
> to incorporate both the crank reference signal and the hall sensor.
>
> [That other tangental project seems to entail understanding analog
> to TTL signal conditioning (to eliminate "ringing" and other noise,
> apparently), and other stuff.  I have no skills or experience in this
> area at all, and others have been less than totally responsive to my
> questions, which is understandable (although the courtesy of a
> reply "at all" to my inquiries, even perhaps telling me to "learn it
> myself", or "go screw myself", if that is what the sentiment really
> is, is preferable to me than no reply "at all", fellow enthusiasts).  Of
> course, none of this is important to anyone else except me, so
> what do I expect.]
>
> Anyways...  I'd still like to hear from anyone who might think of
> themselves as helpful, that has an understanding of some of these
> questions I have.
>
> So, I'm faced with backing off that effort, and need to focus on the
> difficult-enough-for-me requirement for me to understand the stock
> sensor outputs.  Actually, I would probably need to understand
> them even if I was continuing to push for my circuit idea.
>
> I very possibly could be working with incorrect understanding or
> assumptions.  This is what I have to do, as far as I know:
>
> I need to understand the output of the hall sensor, relative to crank
> location.  Apparently this entails the use of many items that I don't
> have possession of or experience with their use.  My current
> understanding, from emails and postings, is that the hall sensor
> output is normally "high" (at 5 volts?) and "low output" window is 40
> degrees wide, and this window is centered (when the distributor is
> indexed where it should be) on the flywheel pin location of 62
> degrees BTDC.  One specific clarification I would like is whether
> this is on the 360 scale of the crank, or is it on the 360 scale of the
> distributor itself.  I would imagine that it is the crank, but since I
> can't measure jack-sh!t currently, I can't confirm anything.
>
> In order to determine physical TDC accurately, it seems I need a
> dial indicator and a suitable mounting base, to make direct contact
> with the piston to find where it is located.  I need help here, both
> with locating and choosing the correct tool, and with learning to
> use it properly.
>
> In order to determine crank position, I also apparently need to
> locate and learn to use a degree wheel.  These items apparently
> get attached to either a crank pulley or the flywheel, and tell you
> how far you are rotating the engine.
>
> In order to measure the output of the hall sensor, I need to possess
> and use an oscilloscope.  I can follow directions if I have them.  At
> this time, I haven't analyzed which wires to hook up to the meter
> (that I don't have).  I need to acquire some different testing leads,
> so that I can probe things without cutting into them, I suppose.
>
> I think that's all I need.  It's what I get for trying to do something
> myself without any resources.  I'm a bit discouraged, but only
> because of the amount of time this is all taking.
>
> I'd love to hear that I'm wrong about how complicated this is, and
> that there is either some other way to get the information I need.
> For example, it was said that SJM's site had the o-scope
> waveforms of the hall sensor.  I didn't find that, I only found the rpm
> and timing reference sensors output waveforms.  Does anyone
> know where I can find a waveform of a hall sensor output?
>
> I'm trying to come up with a solution for standalone engine
> management for a 5 cylinder turbo application, using stock
> sensors, for a reasonable price.  That's not even totally accurate.
> The solution exists already, I just need to provide some data to the
> manufacturer.  I would think this is something that would be a good
> thing, but it feels like a party of one.
>
> If anyone has the ability to measure the output of the hall sensor,
> and is willing to do so, will you please contact me or post to the
> list?  Maybe that's what I should ask?
>
> Or, maybe someone will flame me and/or give me a reality check
> on my thought process here.  I have gotten plenty of negative
> emails, saying not to bother with efi, or that it won't work, or
> whatever other negative opinions that people feel strongly enough
> about to send an email to express.
>
> At the moment, I'm at a low point in how excited and enthusiastic I
> am for my projects.  This kinda sucks.  But I guess it's only
> because I'm trying to do something that I almost can't.  For me, I've
> always wanted to "grow" into whatever person has the skills and
> knowledge to get something done, whatever it is.  I figure, I have all
> my fingers and eyeballs and a brain and all the stuff that the other
> people have that know how to do things, so there's no reason that
> by determination and effort (and time! a big one) I shouldn't be able
> to bring myself up to speed to also know how or have the skill to do
> something.
>
> Btw, I have a bunch of beginner electronics books from Radio
> Shack.  But what I really need to know is mid-level stuff, without
> knowing the whole damn history of the transistor, if you know what
> I mean.  I mean it helps, but only so very little.
>
> It's just all taking so much freaking time...
>
> Thanks for reading.
>
> Later,
>
> Ken
>
> '88 5kcstq, 1.8bar, euros, 150a alt., new clutch and tranny laying
> on ground, "new" to me sport interior and Fuchs laying around the
> garage, cracked windshield, "new" rack *installed*, other crap
> '85 4ksq, "t" project, MC-1 motor on stand, h1/h4 eurolites in
> boxes, Jamex strut brace, 17" wheels/tires, KH intake/TB, fuel rail,
> 2B tie rod, 2-piece EM, 200t flywheel/clutch, 20v head and a bunch
> of other stuff just laying around... wtf?!
> '94 SL2, some mods, driven
> '87 5kt parts
>
>
>