Can anyone help me diagnose high oil pressure? As soon as I turn the key on, engine off, the oil pressure needle shoots up to 3 bars. I have another sending unit that I swapped in and it is the same problem. When I check the resistance between the sending unit post and ground on one, I get .45 resistance. On the other there is no continuity. So ruling out the sending unit I checked the wiring and I can find no faulty lines.

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1990 190E 3.0L

Hmmm... My 87 W201 does the same thing. I haven't gotten around to sorting it out yet.

I did replace the instrument panel with a nicer looking one and the oil pressure gauge still does the same thing. I reckon, at least in my case, it's not the instrument panel causing the gauge to malfunction.

Makes me a little nervous. Just the same as having no oil pressure in my opinion. Makes me think that something is clogged up and oil isn't getting circulated.

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1990 190E 3.0L

If you take apart the dash pod, observe the coil that is adjacent to the gauge. This is a choke which damps the movement. It's wound on a plastic spool, and the spools become brittle and crack, allowing the coil to short to the case. The easiest solution is to insulate the coil with a bit of tape or shrink wrap.

My gauge has always run at full max pressure except when at idle. I thought it was good sign and never worried about it. I replaced the sender once and same thing. Full max pressure.

The gauge is at max with the engine off

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1990 190E 3.0L

Have you checked for continuity between the brown and white wire from the sender to the cluster?
I am not sure what .45 resistance means, .45 ohms? .45 milliohms? .45 mega ohms?
If you are not sure, you could take a 10 ohm resistor, connect it to the brown white wire and the other end to ground, this should pull the gauge to 0 considering the wire is intact.

The wire that plugs into the sender ends in a plug behind the battery. There is continuity there. From the Br/wh wire to ground there is a resistance of .45. Behind the cluster on the the round plug (pin #15) there is continuity there to ground. I took it apart yesterday and could find no broken spool as mentioned earlier. I have the FSM and there is absolutely no mention in how to test the oil pressure. It tells you how to test every gauge and indicator located in the cluster, but not one regarding oil pressure

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1990 190E 3.0L

I have edited my reply, review it.

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