What Sender?

[Baker]

This is on the lower port side of a Cummins 330B. I do know the larger 2 wire
sender is the oil pressure sender. What is the smaller "sender" next to it to the left?

That is the raw water pump in the upper left part of the picture for orientation/reference.

One of the wires coming off of it is lose and I cannot fifure out where it goes to. All gauges and alarms appear to be working properly....although I did "lose" 10psi of oil pressure when I changed to the current gauges and senders. Pressure is still within spec but have been meaning to get a murphy gague on it to see what the actual pressure is.

 

[kapnd]

Looks like an oil temp sensor.

 

[jleonard]

Looks like a "low oil pressure" switch. Normally closed (sounding the buzzer when you initially start or when oil pressure gets low), with about 15 psi it opens and stops the buzzer.
That's what it looks like to me from the picture.

 

[Ski in NC]

Not a Cummins part. Must have been added by the boatbuilder. Looks like a low oil pressure alarm switch. Not temp as oil does not circulate there. One with two wires drives the gauge.

 

[ranger58sb]

One of the wires coming off of it is lose and I cannot fifure out where it goes to. All gauges and alarms appear to be working properly....although I did "lose" 10psi of oil pressure when I changed to the current gauges and senders. Pressure is still within spec but have been meaning to get a murphy gague on it to see what the actual pressure is.

My vote is that it's the "low oil pressure" alarm sender, and it looks like what's on our 450s. You can test, maybe; if the buzzer doesn't sound when you turn the key on (but before actual engine start) that's likely what it is. If you reconnect the wire and the buzzer works afterwards, there ya go.

What gauges and senders did you switch to? I've been working a "lack of precision" issue with new gauges and old senders...

-Chris

 

[Baker]

Well the low oil pressure alarm works just fine??? At least it buzzes when I turn the key on.

 

[Baker]

What gauges and senders did you switch to? I've been working a "lack of precision" issue with new gauges and old senders...

-Chris

I went with Isspro....both guages and senders and new wire. I was tired of dealing with "lack of precision". But....I think some still remains. If I had to do it all over again I would just get OEM Cummins panels which are VDO. I went with Isspro because they were the ones that make the pyro/boost gauge and I wanted to add those. I also went to digital tachs. I thought I would miss the "sweep of the needle" of an analog tach but I don't. And obviously these things are dead on. You only have to input the number of teeth on the flywheel and then hook it up!

 

[ranger58sb]

Well the low oil pressure alarm works just fine??? At least it buzzes when I turn the key on.

Hmmm....

I went with Isspro....both guages and senders and new wire. I was tired of dealing with "lack of precision". But....I think some still remains. If I had to do it all over again I would just get OEM Cummins panels which are VDO. I went with Isspro because they were the ones that make the pyro/boost gauge and I wanted to add those. I also went to digital tachs. I thought I would miss the "sweep of the needle" of an analog tach but I don't. And obviously these things are dead on. You only have to input the number of teeth on the flywheel and then hook it up!

Thanks. I went with Aetna digital tachs; easy.

The CruzPro digital oil pressure guage seems to work fine but the OP senders we have (older VDO) and the options CruzPro offers don't match up all that well. I'm thinking about replacing the original VDO senders with newer generation VDO products.

-Chris

 

[LarryM]

John,

Pretty sure that's a single-terminal oil pressure switch, and your buzzers work because it grounds through the switch body which is threaded into the engine block. I believe you will find the black wire is a ground for use with floating-ground switches (two terminals) like this, which are used in some installations, but not yours.

I have the same type of harnesses on mine with un-used black wires on the single-terminal sensors. Each sending unit and switch has both a signal and ground wire provided in the harness, see item 7 below.