hall sensor on a '85 4kq? (5 window type?)

[Ken Keith]

Quoting Orin Eman <orin at drizzle.com>:

> > I'm still researching the ignition timing reference pin location for
> my
> > engine management system conversion.  I supposed I've
> > determined that the pin is located 62 degrees BTDC for cylinder
> > number 1 (?).
>
> Correct, 63 BTDC on cyl 1.  135 teeth on the flywheel.

Hi Orin,

63?  Not 62?  SJMAutotechnnik.com says 62, which you agreed with last month here: http://www.audifans.com/pipermail/quattro/20011205/040974.html

I found that last night while searching.   I'm sure it's a typo, but this is important stuff to get right! :-)

> > Now I'm wondering how the stock 4kq hall sensor works.  I know
> > the hot ticket for some EFI conversions are to use the NF/NG
> > ignition system, which has a 5 window hall sensor.  Is this is the
> > case with the 4kq as well?
>
> Yes, 5 windows for 4kq.

I just have to figure out how to use that part of the 4kq system along with the long block of the MC-1 motor.

> > I remember the NF/NG system is preferred over the 4kq system,
> > but that's because of the knock sensor.  My engine management
> > system will have one or two knock sensors of it's own, so that's not
> > important to me.  However, if it is a 5 window hall sensor as well,
> > then I may be all set.  Anyone know?
>
> A good knock control system will need to determine the compression
> stroke on cyl 1.  Better make sure you can do that with the 5 window
> sensor along with the timing pin.  You need to know what cyl is firing to
> determine which sensor to listen to, as well as what scaling to apply to
> the knock signal.

Yeah, I'll have to figure out if the combination of 5 window signal and timing reference pin is usable.

I don't know about the internals of the way the knock sensing system works.  I guess to make it less likely to get false alarms, you would want to not listen to the knock sensor on the other side of the engine from the cylinder that's firing.  I can probably find out about that.  As for the scaling, I didn't see anything in the owners manual for the LinkPlus that mentioned having anything to adjust.

Does anyone care to comment on where I would splice into the hall sensor to connect it to the standalone ECU?

Luckily, I haven't had to mess with the hall sensor on either of my previous Coupe GT's.  I knew a guy that supposedly fried his, which he said happened when he was trying to check for spark incorrectly, but I don't remember how.  I know if you pull the plug, plug it into the wire, and ground the plug threads/body, that you should be okay.  Perhaps he fried it by not grounding the plug threads/body?  Anyways, the point is that I have not experience in the hall sensor area.  I need to find a site like SJM's for 4kq's.  Next, I'll spend some time at Huw's site to see what's up there.

Thanks!

Ken

p.s.  Regarding Electromotive, there are plenty of other systems out there that will work with a 5 cylinder.  I know of 034EFI, Autronic, EMS, Motec, Haltech, and LinkPlus.  At least according to other people online using them, and the factory documentation.  Just vote with your dollars.