5ktq Possessed oil pressure auto check

[John Cody Forbes]

On Oct 19, 2010, at 10:15 PM, John Cody Forbes <cody at 5000tq.com> wrote:

> 
> 
> On Oct 19, 2010, at 8:20 PM, Huw Powell <audi at humanspeakers.com> wrote:
>> 
>> Are you sure the low pressure switch is NO?  I thought it was NC so a broken wire would set it off.
>> 
>> You apparently have plenty of spare cars to swap the sender into and test, why not try that?
>> 
>> -- 
>> Huw Powell
> 
> In the mechanical testing side of the Bentley (page 17.10) the testing procedure indicates that the .3 bar switch is NO and the 1.8 bar switch (white) is NC. Interestingly it also states that the white switch is active over 2100rpm. My issue occurs only below about 1200rpm. Hmmm. I would expect an issue with the black switch to set the warning off when crossing 2000rpm in that case. Another interesting note is that it says that the black switch will illuminate the light, while the white switch illuminates the light and the 3 tone audible warning is activated. My issue includes the audible warning. Hmmm x2.
> 
> I'm going to wiring diagrams now. I wonder about the tach signal to the autocheck. This is an EFI car, but the tach signal is using the stock wire in the ECU harness. Maybe the autocheck uses a secondary tach signal wire from somewhere I'm not tapped in to.

Aha! Yeah that was the right line of thought. Both the ISV controller and the autocheck get their RPM signal from that extra wire on the top of the ignition coil. I'm running coil-on-plug, the stock coil (and that wire) are no longer in the car. I'll have to get an RPM signal to the autocheck system. The idle oil pressure must be below 1.8 bar and the system defaulting to the white switch since it isn't getting an RPM signal.

Thanks for sending me back to the book Huw. That's just what I needed to prove that it's all down to my own stupidity ;-).

-Cody (mobile)