Oil pressure gauge pegged

rlsimmonspi · Nov 3, 2018

Got 2 CAT 3208s. Oil pressure guage on one was pegged with ignition on, running or not. Replaced sender, VDO 150 psi, warning contact 11 psi. Guages are VDO, 150 psi. Guage stopped pegging with switch just on, but now pegs when running. Any thoughts?

kchace · Nov 3, 2018

Yes, 2 suggestions. VDO oil pressure gauges have a large number of different senders and you must get the right one. If in doubt at all about actual pressure, install a known good mechanical gauge right on the engine to verify.

https://www.vdo-gauges.com/sensors/pressure-sensors-switches.html

Ken

Maerin · Nov 3, 2018

Murphy mechanical gauges can confirm what you're seeing at the instrument panel. I really love having these where I can see them every time I do an engine check. You could rig an oil pressure mechanical gauge without too much trouble, that would tell the tale on your oil pressure. The temperature gauge relies on a thermocouple sender that must be installed in the head cooling jacket. So it would require dropping the cooling system. I'm not sure if the rubber housing on these came from Murphy or Cummins, it was on the boat at purchase.

jleonard · Nov 4, 2018

I always replace both sender and gage so I know they are compatable.

rlsimmonspi · Nov 4, 2018

Just stopped in to harbor freight and picked up a mechanical guage. VDO website says that the senders are matched to the guage according to the max psi on the face of the guage. I’m thinking there’s more to it. Thanks for your response.

psneeld · Nov 4, 2018

Dual or single gauge sender installed?

rlsimmonspi · Nov 4, 2018

Don’t know how to tell. Boat has upper and lower helm. VDO seems to make several senders for 150 psi guages. Picked the first one I saw with a warning alarm at 11.4 psi. Single wire goes from sender to lower guage. Wire to upper guage is spliced in at lower guage. Haven’t seen a thing on line that differentiates senders as one or two guages. Could you point me in that direction? Thanks for the response!

TowLou · Nov 4, 2018

Electronic gauges or mechanical? I'm gonna assume electric. If so check wiring as well maybe it grounded out if sender was changed. Nothing better imo then a mechanical gauge for oil pressure. Just have to keep a eye on the hose every now and then.

psneeld · Nov 4, 2018

Should have been on package single or dual.

Manufacturer websites may have resistance values (Faria does) for single vs dual.

Could check with just about anyone with a part number.

Larry M · Nov 4, 2018

psneeld said:
Should have been on package single or dual.

Manufacturer websites may have resistance values (Faria does) for single vs dual.

Could check with just about anyone with a part number.

If it’s a single gauge and installed as a dual, it probably won’t read correctly as psneeld mentioned because of the resistance.

FlyWright · Nov 4, 2018

You've got twins so you can hook the 'bad' gauge up to the other side to see the effect. Also, do you have a FB with duplicate gauges? If so, what does it indicate?

C lectric · Nov 4, 2018

Larry M said:
If it’s a single gauge and installed as a dual, it probably won’t read correctly as psneeld mentioned because of the resistance.

Any electric guage I'm aware of needs specific senders for single guage and dual guage setups.

As mentioned a single guage sender used for dual guages will misread. Same in reverse.

Contact VDO or the distributor and find out instead of guessing. Get the specific model number off the back of the guage first.

FF · Nov 5, 2018

"Murphy mechanical gauges can confirm what you're seeing at the instrument panel."

They can also set off an alarm at a selected set point , should your instrument scan not be 100% attentive .

This is good insurance when a guest has the con , and can look for other boats , but has zero idea of what the instruments mean.

Oil pressure gauge pegged

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