Strange temperature indication

aero3113

Last week I noticed my port temperature was showing a little high, around 190. Then it went down to 100. Today it happened again but both were reading very low and came up to 150. On the trip home starboard side came back to normal temp 175 and port stayed low at 150. What’s going on??

LaRea

I'd say ground block, but I know you've given yours a makeover.  If the temp really was 190, you'd have alarms screaming all over.  That leaves only the Faria gauges, right?

aero3113

@LaRea , I’m assuming that the real temp indication comes from the computer and the gauges are just for reference? The temp/signal from the computer would set off the alarm and the gauges have nothing to do with the alarm?

LaRea

Right -- they are analog gauges that display voltage signals from the computer.  Clearly, your engine wasn't running at 100 degrees, so it has to be a problem with the gauge.  Maybe start by reseating the plug on the back of the gauge?

aero3113

I was thinking the same, I’ll check the connector. I should’ve given the gauge a couple of taps with my finger to see if that woke them up.

captkevin

Also at the sending unit?

YYZRC

@aero3113 don't you have a VVM dongle that you haven't installed yet?

Spyderweb

@aero3113 the solution is vessel view mobile.

aero3113

YYZRC said:

@aero3113 don't you have a VVM dongle that you haven't installed yet?

No, I ended up not buying it.

aero3113

Spyderweb said:

@aero3113 the solution is vessel view mobile.

Yea,yea, I know…

Liberty44140

I had oddly low temps reading on my Volvo and it was the sending unit that had gone bad. 

Pat310

Odd that both senders would start acting up at the same time. I would check the ground behind the dash panel

GMSLITHO

does the temp change if you raise and lower the drive maybe a kink in the hose 

aero3113

I played around with it a lot today. I checked the grounds, I checked the connectors on the back of the gauge, I checked all of the connectors behind the dash panels, I checked all of the connectors on the port engine and I tried a different temp sensor that I had. Still no change on the port temperature reading. The starboard side has been reading normal since I first posted this issue.

aero3113

GMSLITHO said:

does the temp change if you raise and lower the drive maybe a kink in the hose 

It’s not overheating so I don’t think it’s a water supply issue.

Grahamu

When were your thermostats last changed?

LaRea

No alarms, no change in performance ... gotta be the instrument or the wiring.  You wouldn't expect both senders to fail at the same time.

aero3113

Grahamu said:

When were your thermostats last changed?

@Grahamu , I was just thinking thermostat. It’s been a couple of years, would the engine run at that low of temp with a stuck open thermostat?

YYZRC

I had this issue on my Four Winns.  Ran cold. I replaced the temp sender, gauge, thermostat... never did figure it out!

aero3113

I don’t know why I didn’t think to use my Rinda scan tool!🤦🏻 It would definitely let me know exactly what temperature the engine is running at!

aero3113

What temp thermostat are you running?

YYZRC

160

aero3113

Thanks!

aero3113

I finally got around to checking the thermostat this morning on the port engine, it was stuck open!! I will replace both thermostats today 👍🏻👍🏻.

YYZRC

Nice find! The gasket under the thermostat is a pita to get out. 

aero3113

Back in business!!

rasbury

  

aero3113

What’s crazy is that both gauges had the same issue at the same time but the starboard side bounced back. I was in deep water so didn’t suck up any sand. Definitely thought it was going to be an electrical issue.

davidbrooks

I don't understand the temperature fluctuations. It makes sense why a stuck open thermostat would read low temperatures but it doesn't make sense in my head why it would fluctuate like that.

aero3113

Only thing I can think of is that they were sticky and causing the temp to fluctuate. One freed up and the other one stuck open.