Temp gauge troubleshooting

[Chrisrog]

My temp gauge seems to hover just below 140. At first I thought I might have a sticking thermostat, but realized it stays there even with the ignition off.

So even though the problem is likely the gauge or wiring, I replaced the impeller and thermostat, rinsed out the strainer and inspected the transmission cooler screen just to have a good starting point.

So I need some help with troubleshooting the temp sender and gauge. I'd like to know how to properly troubleshoot rather than just replacing parts to see what fixes it.

What changes with the sender as the temp goes up and down? Voltage? Anyone know the values?

Is there a process for testing the gauge? How do you cycle them through a range of motion?

Finally, I know my boat had some gauges replaced at some point. Is this temp gauge original or replacement? It's a 2002 SAN w/ Excaliber 330 engine (GM5.7L)

As always, thanks everyone for the input.

[Chrisrog]

It appear I never had a response on this, nor have I had a chance to fix it yet but I did just find the tleflexmarine.com website and a Tech reference manual that tells me how to troubleshoot. I'll be working on solving this problem this weekend.

So my next related question: the PCM parts book shows a temperature sender (R020003) and a temperature sensor (R020019). I'm guessing the sensor goes to the motor and the sender goes to the gauge? If so, what is the purpose of each?

Are my gauges factory original? If not, could my poorly working gauge problem be the OEM sender isn't compatible with my gauges?

[mpost]

NP lists those numbers
as WATER TEMPERATURE SENDER – 1/2 INCH NPT- PCM 351 FORD (EXCEPT GT40), # R020003
and WATER TEMPERATURE SENDER, PCM (SENDING UNIT FOR THE ECM ON MOST GM ENGINES), # R020019
so I would make sure you are liiking up the parts in the PCM book for your GM 330 engine. The 200003 is the sender that runs the temp gauge but says it is for Ford 352. IF you take the wire off this sender and touch it to ground it should peg the needle hot. The sender works off of changeing its ohm resistance with temperature change. I do not know the specific values, but if your gauge never moves when teh key is turned on and the engine is cold, it sounds like it is connected wrong or broken. the ground test should tell you that.
the 20019 as stated feeds the engine temp to the ECM for engine management. FYI the R020002 is listed for GM 5.0 and 5.7 liter engines.

[Chrisrog]

NP lists those numbers
as WATER TEMPERATURE SENDER – 1/2 INCH NPT- PCM 351 FORD (EXCEPT GT40), # R020003
and WATER TEMPERATURE SENDER, PCM (SENDING UNIT FOR THE ECM ON MOST GM ENGINES), # R020019
so I would make sure you are liiking up the parts in the PCM book for your GM 330 engine. The 200003 is the sender that runs the temp gauge but says it is for Ford 352. IF you take the wire off this sender and touch it to ground it should peg the needle hot. The sender works off of changeing its ohm resistance with temperature change. I do not know the specific values, but if your gauge never moves when teh key is turned on and the engine is cold, it sounds like it is connected wrong or broken. the ground test should tell you that.
the 20019 as stated feeds the engine temp to the ECM for engine management. FYI the R020002 is listed for GM 5.0 and 5.7 liter engines.

It's the NP description that caused me to pause. The PCM parts book for the 330 engine shows both parts on my engine with the numbers as above. I looked up one of the numbers and it came up as the Ford part.

I suspect my gauges have been changed out but I don't know for certain. If they have, I guess its possible that the OEM gauge gives a different reading from the Teleflex gauge, but without accurate info on the OEM gauge, I don't know how to compare the 2.

[eamonharper]

any luck with this? I'm having issues with my temp gauge. It is essentially off at start up but turns on intermittently while in use. Not sure if its the gauge or the sender.

[Chrisrog]

I haven’t had a chance to dig into it, but I found owners manual info on the Faria website that includes a troubleshooting guide.

[Chrisrog]

Or was it Teleflex….now I can’t remember which gauges I have. This summer has been a bust for boating.

[JayG80]

Your temp and oil gauges look identical to the ones in my old 2002 Ski Nautique. Brand is Teleflex.

[biacs]

Is there any chance the temp gauge is powered through the computer? One trip my fuel gauge/perfect pass was dead. The next time out just the temp gauge was dead. I know temp sending unit reading because I can see temp on the digital readout.

So I’m wondering if there’s a gremlin with under 14 V at start up maybe the computer box doesn’t recognize all the gauges if they run through the box?


2006 SANTE - Bull in a China Shop - Central IL