AO

Over the weekend I decided to play around with the digital dash diagnostics. I found something very interesting.

Lately, I've been very cognisant of my oil pressure. My gage has only been going 4.5bar, and I've been curious if this is a gage problem or an actual oil pressure problem. While reading the digital dash diagnostics paper (if you have Jim's CDs it's on CD1 under "Other") I realised that I could get a digital readout of the oil pressure!

So after a little running around, I snapped this picture. Sorry for the lousy quality, but it was taken with my cell phone.



What's interesting is that from 0 - ~3bar, the analog gage seems to be pretty accurate, but any higher than 3bar and the analog gage doesn't keep up. You can clearly see that I'm running 4.1bar, but the gage only shows about 3.5bar.

So, if you have a digital dash, you should be able to verify your gage's accuracy using this method. Have fun!

Chris

Had this problem with my 91, the gauge would not reach 5 bar, replaced the sender and problem solved.

Where the sender is located it collects a whole bunch of garbage through that pinhole, if you ever remove put it upside down on some paper and come back the next day and see what has drained out.

I like the diagnostic feature, very cool

Chris

AO

Chris, the problem is not the sender because they use the same sender. The problem is the gage. This method just shows the difference between the digital readout and the inaccuracy of analog gage. But if they had been the same... I would have looked at the sender.

Chris

Dugh, my bad, should have had more coffee before typing ....

Mike Frye

So Andrew,

If your needle used to go higher but now it doesn't. Is that just a sign of age or something else?

Is there something that can be done to get it back up where it belongs?

AO

Funny Mike!

Taking your question seriosly though, I can't say what the casue is. But for the fix, I think the only way to fix it would be to either physically adjust the needle or periodically do this test to see what the relationship is.

Mrmerlin

the other thing you could do is replace the old sender and see if anything changes. Just a thought but an expensive one

shadowknight

I have a digital dash 89 s4 how do I turn on the diagnostics

AO

From the CD's:

The connector they refer to is the round diagnostic port under the cover between the passenger seat and the door.

borland

Andrew,

According to the Porsche Service Guide, "Diagnosis of the Instrument Cluster", page 9, your analog gage should read about 4.5 bar, when the digital display reads 3.7-4.2 bar.

So, I'd say your analog gage at 3.5 bar is pointing too low.

Shark Attack

just pull the pointer off the oil pressure gauage and move it over... this kinda concept also works well when you have that silly antilock brake light on... remove the bulb.. Or when the brakes squeel... turn up the radio. all very good fixes

borland

Before taking a fork to the pointer, you might consider taking readings similar to as shown in the guide, from low to high, and again going from high to low. That would also give you a measure of the analog gage hysteresis.

AO

Here's a question... What is the difference between Sensor 07 -"Oil Pressure Indication" (pg 9) and Sensor 08 - "Oil Pressure Sensor" (pg 10)?

I've already taken some readings. What concerns me is that below 3.5 bar the gage matched the digital readout. I think I would rather have it read accurately on the low-end than on the high end. But when I pull the pod this winter, I may 'tweak' the needle a hair as the needle stops at 4.5 bar.

Vilhuer

Quesing one is ok/not ok light and another is actual needle.

IcemanG17

Okay
digital dash in way cool!!! Mine never ever reads a full 5 bar....about 4.7 is as high as it gets....running M1 15-50.....