Re: Tachometer Help?!!

[steveb@newkla.kla.com (Steven Buchholz)]

> >Any requests regarding packaging or gauge style, etc.?
> 
> I'm Ok with the stock tach in dash; but, I am interested in the lights as well.

My friend's original idea is a "black box" that is in line to the tach, so 
this should be very doable ...
> 
> I also want to defeat the rpm limiter on the 4000Q. Seems, according to the
> bentley manual, the limiter is fed by terminal #1 from the coil to the fuel
> pump relay. Anyone have any Idea what's inside the relay that triggers the
> fuel pump off at 6500 rpm?

I would imagine that it is some type of circuit that checks the time between 
tach pulses (i.e. sparks).  The same circuit shuts off the FP when the engine 
stops running.  I would imagine that the circuit inside the relay is fairly 
simple and could be defeated or modified to set a higher cut-off.  The prob-
lem is that I do not have such a relay to reverse engineer.  If someone had 
the appropriate FP relay (doesn't matter if it works or not), I could take 
it apart to figure it out.  I've done similar things on other Audi relays ...

Steve Buchholz
s_buchho@kla.com
San Jose, CA