OK, read the archives... I'll ask to make sure.

If the car has been left off overnight, I turn the key to the "ON" position (without starting the car), the pressure gauge gets pegged at 5. It stays pegged when the car is started and running.

Looked under the car, connections are clean and tight. Did not try to look for a broken wire between the engine compartment and the car.

Plenty of oil in the car.

So, this is probably the sender, right? Does the oil pressure idiot light run using info from the same gauge? I assume that the sender is just providing a resistance value. Does anyone have a set of resistance values vs. oil pressure values that I use to check the gauge?

Thanks!

Kevin

 

It was working fine, then just started acting up like this? You're sure you did not mess with the connections?

If the wires are backwards on the sender, it will peg the gauge. If it just happened by itself, and the wires are good, it probably shot.

 

Oh yea it's shot. I ordered my new one from vertex for $45.........problem solved.

Mine happened just the same way.

 

exactly the same with me. Dont bother testing it it is worth the 50 bucks just to buy it.

Christian

 

It had been working fine. On the other hand, I haven't driven the car very much in the last few months.

I did not move the connections, or remove the wires.

BUT...

I did fix a broken wire in the passenger's side headlight wiringe harness. But I don't think that sender unit's wiring goes into the wiring loom at that point. I didn't look carefully enough to be sure.

And I cut open the harness at a point where the headlight wires had already split off from anything else in the harness.

So, I'm thinking that the sender died. I will look at the circuit to see if the gauge can be tested tonight.

Kevin

 

OK I read the clarks-garage site.

Is removing the pump really necessary? Or can I loosen the belt and move the pump out of the way enough to work?

Also, the instructions mention a 24mm _stubby_ wrench. I looked today - is the clearance really that bad?

How tight should this sensor be (I'm having some recent bad luck with over-torquing things).

Thanks!

Kevin

 

You "may" have to move the pump... it's a crapshoot. Torque is low - maybe 20-25ftlbs. There is a sealing ring crush washer.

Good Luck!

 

No you don't need to remove the (power steering?) pump. I did it last weekend with a normal length 24mm Craftsman wrench, turning it bit by bit with the wrench in three different positions. The anti-roll bar was more of a pain than anything else.

Torque is 35Nm or 25 ft lb. It would need to be a 'very special' torque wrench to fit though.

Make sure you get a new sealing washer (I got mine from Sunset Porsche and it was included). You may need to swap the connectors off the old sender unit and have something handy to catch the oil when you unscrew the old one.

Chris

Edit - sorry, should have noticed yours is a 924s. Not sure if it differs from a 944S in the amount of space available.

 

Try to disconnect it - it should be fail-safe if a ware is broken the pressure should read zero to draw your attention. If it does, the instrumet cluster works fine and it is your sender. Otherwise not sure.

I had to remove everthing - sway bar and the pump to get comfortably to the sender. But it just me...
Hope this helps.

 

Sasha, sorry to contradict but I heard from my mechanic that the resistance increases as the pressure goes up and the senders normally fail to a broken circuit, hence being pegged at 5 bar.

If you ground the pressure sensor cable (not the idiot light cable) then the gauge should drop to zero if it is working.

The idiot light and gauge are independent although combined in the same unit.

Edit :
I just took the old sender apart and confirmed zero resistance at no pressure. Just in case it is handy to someone, the idiot light is the terminal marked by the dot of blue paint and connected to the solid blue cable.

Chris