VDO viewline 150 PSI gauge pegged

[Terry Kerr]

Port gauge pegs past 150 psi as soon as I turn on the on switch. I don’t even have to press the start button to start the engine.

Removed the sending unit and hooked up a manual gauge and it reads about 40 PSI at idle.

Starboard gauge works fine.

Swapped wires up top and ….. port gauge now works fine (reading the starboard sending unit) and starboard gauge pegs (reading the port sending unit).

Assumed this meant both gauges were fine and starboard sending unit was fine.

Therefore must be something wrong with the port sending unit.

Bought a new SBAR sending unit and it does the same thing (pegs before even starting).

If not the gauge or the sending unit then what? wiring?

Followed the two wires from the sending unit on the port side of the motor and they seem to wriggle there way between the after cooler past the turbo and maybe even down to somewhere around the starter on the starboard side of the motor, where there’s a bunch of wires. somebody painted everything white and now hard to tell what’s what. It’s a diesel, Why so many wires?

Any background appreciated or possible next steps?

Topic

[Tony Athens]

Your engine block is a common ground, or at least it should be.

Plenty of factory wiring diagrams on this web site

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Terry Kerr

[Terry Kerr]

Thought they were both grounds

Good info

I thought one went to the gauge and one went to the buzzer. I’ll see if I can rig up another ground.

[Tony Athens]

You have lost the ground to the sending unit — One of the terminals on the sender goes to the gauge the other MUST to to a common ground.

[Author]

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