I have noticed recently some disturbing oil pressure reasings on my dash display [3 pin sender]. I replaced the sender about a year ago but my wiring, expecially around the 14 pin conector was a bit of a basket case, with much of the insulation crumbled. I cut back the wiring and installed some extension pigtails using screwed connectors but did nothing at the sender end.

For the most part the signals have been reasonable with cold indicated pressures quite normal but whne warn the signal can be a bit erratic and more worryingly, seems to show a lowe roil pressure of about 3 barg however when this happens the indication is not characteristic of what I expect to see relative to rpm's.

Now my dimemma is whether I have reduced oil pressure for real or whether it is a case of false signals. I can well believe that as things heat up there will be more "signal losses". The motor itself feels healthy enough and I cannot think of any scenario that should cause a loss of oil pressure.

I am thinking of trying to put some new wiring in to test for signal loss. I understand that the connector is no longer available as an available spare [Roger?] but looking at the pins it should be possible to fit some kind of ocnnector to each pin individually- anyone know of any work arounds for this?

Any thoughts on the above in general appreciated. I am reticent to run the motor until I can prove whether there is a genuine mechanical problem or whether it is just a signal error.

Regards

Fred

 

If you say erratic, does this mean that the instrument "flickers" sometimes or does not indicate anything at all?
Common source of problems at the gauge is the ground soldering spot...

 

add some deoxit spray to the wires ,
this will improve conductivity.

Note there could also be resistance in the repairs already made,
the deoxit should reduce the resistance

 

Schocki,

The needle sometimes flickers and jumps to full scale deflection suggesting connectivity issues but generally gives sensible reading when cold. Then when hot, the needle seems ot settle low [around 3 barg] but then does not seem to move much at all irrespective of rpm's and certainly not proportionately to rpm's. if the oil p ressure readings are correct, then even if they were genuinely low I would expect to see normal type proportionality to rpm's which is not really the case. Thus I suspect [hope] it is a gauge reading error rather than a wear problem.

I know my engine bay cables are in generally poor shape and I dare say it is just as possible that from the 14 pin connector through to the gauge head unit there could be problems as well not to mention the gauge head itself.

I have had problems with the tach signal regularly breaking down at rpm's over 5k rpm for some time and had the same issue with my late S4. I put this down to degradation probably accelerated by our relentless heat.

In reality I problably need to replace all the engine bay wiring/connectors.

The deoxit applicaton is also on my radar as I try to work out what I need to purchase to rectify this problem set. Just that with ambient temps currently running low 40's centigrade I am not in too big a hurry.

Regards

Fred