Multimeter (was Re: '86 C-GT Alternator...)

[ejfluhr@austin.ibm.com (Fluhr)]

Phil Payne writes:
>Look for quite comprehensive volt and ohm ranges, but don't worry if there's
>only a single relatively crude current range.  The most delicate current
>measurement on any Audi is the 430ma (half an amp) on the ISV.  A
>"diode" test position is also a good idea.  The Draper device has all of
>these.

Sorry to disagree, Phil, but the CIS-E and CIS-E III systems use a pressure
actuator current ranging in the tens of milliAmps.  At normal operation at
sea level, the pressure actuator current while running closed loop should
be somewhere around 10mA.  Lean stop is 0mA while rich stop is 20mA. 

The JT engine in the 4000q and the KX/NG engines in the Coupe GT series
both use a form of CIS-E with these pressure actuator currents.  I think
the mid-to-late '80's 5000 and perhaps 80/90 w/2.3L normally aspirated I5
also used the CIS-E systems, though I am not as familiar with these cars
and do not know for sure.

The SunPro CP-7678 is a great multimeter in many respects, but its current
measurement capability is poor.  It cannot measure down to single digit
milliAmps.  If you can afford to spend a bit more money, I would suggest
looking for a multimeter that CAN handle milliAmp measurements accurate
to single digits, _especially_ if you have a CIS-E system.

Later,
Eric
'85 Coupe GT
---
Eric J. Fluhr                                Email:  ejfluhr@austin.ibm.com
630FP Logic/Circuit Design                   Phone:  (512) 838-7589
IBM Microelectronics Div.                    Austin, TX