Re: VDO Oil pressure gauge

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

> Has anyone added an analog oil pressure  gauge?  Surplus Center has these 
> nifty 2" VDO mechanical gauges for $8.95.  What does the existing idiot oil 
> light measure?  Where could the required oil pressure sender be placed?  My 
> idiot light keeps going off intermittently and I'm concerned it may be low 
> oil pressure since the oil level is fine.
> 
IME the switches go out more frequently than actual pressure problems occur.
It is always best to assume the worst though.  I have installed analog oil
pressure gauges on both the urQ and the Fox.  VDO made a sending unit that 
had both the pressure gauge output and switch for the idiot light.  I can't 
tell you exactly where the switch is on the 5k, but you should be able to 
replace the low pressure switch with the gauge/switch unit and have every-
thing work fine.  I believe the LP switch is mounted on the drivers side
of the engine, down low near cyl 3&4.  

Both of your 5ks should have the "Dynamic" oil pressure monitoring system.
This means that there are actually two pressure senders and an electronic
monitoring circuit.  The low pressure switch is pretty much standard faire,
a switch that closes when the pressure is below some low value like 6 PSI.
The high pressure switch closes at high pressure and there is a module on
a relay panel that receives a tach signal and the switch input.  The cir-
cuitry expects the high pressure switch to be closed whenever the engine 
RPM is greater than a threshold (2500 RPM?).  My recollection of the wiring
is that the output of this electronic module is another ground signal which
is effectively in parallel with the normal low pressure switch.  It seems 
to me that if anyone is having intermittent trips of the high pressure 
module they can eliminate them by simply pulling the module out.  The low 
pressure circuit will operate as most every other car in the world does.

You said "mechanical gauge" but then refer to it as needing a sending 
unit, which would be electrical.  Are the gauges at Surplus Center 
electrical gauges that rtequire sending units, or are they mechanical 
units with tiny hoses?  Do you get catalogs from Surplus Center on a 
regular basis?  If so, I'd appreciate it if you could forward their 
phone number to me, it seems like they have interesting bits for sale 
from time to time.  TIA!

Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)