No Oil Pressure!

['956Wheel]

With the ignition in the on position the "dummy" light comes on and goes off upon starting. I picked up a sensor and grounded it, hooked it up to the wiring with 40 PSI air and the exact symptoms occur.



Any help and ideas would be greatly appreciated!



Mike

 

[Rammin On]

Have you checked the gallery pressure with a mechanical guage?

 

['956Wheel]

Rammin, Where would I hook it up?



Mike

 

[Dieselnerd]

'956, are you saying that with a new sensor hooked into the circuit and 40 psi of air applied, your oil pressure gauge on the dash still reads zero? If this is true, you either have a bad gauge, an open in the wire going to the gauge from the sensor or no power to the gauge. Check for continuity between the sensor and the gauge. This is where the wiring diagrams in the service manual come in handy. The sensor is just a variable resistor and the gauge varies with the resistance. As Rammin On said, it wouldn't hurt to hook up a mechanical gauge just to ensure you really have oil pressure and don't ruin the motor but from your description it sounds electrical. You may have to pull the instrument cluster to find the problem. Maybe others will have more ideas... Hook the mechanical gauge right into the spot where the pressure sender screws in.

 

['956Wheel]

Rammin, A gauge in the 1/8 NPT hole on top of the oil filter mount gets 28 PSI @ Idle... . so my guess is electrical... uggh! By looking at the BIG GREEN book it shows a gray wire going from the sending unit to the gauge with nothing in between... what could go wrong?



Mike

 

[Rammin On]

There is probably an open somewhere ..... like Dieselnerd stated ... you're gonna have to dig into the inst cluster and start having fun with your trusty meter ... .



Your oil pressure is good ... .



good luck! let us know what you find

 

['956Wheel]

Pulled the cluster out and checked all that I could, Had to put it together to go get my daughter from school. I would bet its the gauge itself. Does anyone know if you can get the oil pressure gauge w/o having to get the whole cluster... it attaches with 3 screws to the "trace board".



Kinda sucks driving around with nothing on the gauge!



Mike

 

['956Wheel]

Follow-up:



That big square plug under the dash near the clutch with a 10mm bolt holding it tight has an intermitant (sp) connection. The plug contains the wire from the sender to the gauge. When "solved" and dash all together... . gauge does not work!

After undoing the plug to see if cleaning would help..... not enough room or length of wire to do so, put it together it works

Then after two or so minutes it doesn't

Tomorrow is another day... . under the dash work sux!



Mike

 

['956Wheel]

FIXED... ... . Kick back tomorrow!



Took a couple pins (like in a new shirt) soldered a couple short wires to them and used the long jump lines to work closer and closer till I found the break... that big white plug that you can't get to the backside..... just jumped it... . problem solved.



Mike



P. S. That wiring under the dash is the sloppyest mess I have ever seen... IMO Just like all thsoe blood sucking cable ties under the hood!