1999 Volvo Penta 4.3 - no reading on temperature gauge

[drew_caplan]

After my recent engine replacement, I am not getting any reading my temperature gauge. I believe after reading on here the sender has to be grounded and sends a ground signal to the gauge (correct me if I am wrong) so I am going to check three things:

1. Ground the wire at the sensor to a good ground to see if the gauge and wiring is good.
2. Check the location of the sensor, I had to move it when I replaced the head and it is tucked right tight beside the thermostat.
3. Check the thermostat to see if it is opening; looks like I could be using colder than 100 degree water all of the time and the engine never warms up enough to read on the sensor.

I will report back shortly but wanted to share my journey for others incase they experience the same thing.

 

[ESGWheel]

Easy peasy to test and do not forget to check the +12V at gauge.
See post no. 9 of this link
And post no. 3 of this link

 

[drew_caplan]

Well I tested the wire at the sender with a good ground and the gauge spiked, tells me that either the thermostat isn't working properly and the engine is never getting over 100 or that the sender isn't working correctly. Have a look at where I had to place the sender with this new intake. Things didn't quite line up as nicely as the OEM intake so I am not sure if that might be the issue either.

 

[ESGWheel]

I’m not familiar with this design but looks ok. Hopefully others will chime in.

Get yourself an IR gun > they are inexpensive (u don’t need a high end one) and a good diagnostic tool to have.

Also if u do not mind: start another post under “Other > iBoats Fourm and Website Issues “ on how you are using IBB to post pics - thanks!

 

[Horigan]

Realize there are two temp "senders". One is an alarm temp switch that completes a ground and triggers the high temp alarm, the other is a sensor that has variable resistance that is read by the gauge.

 

[drew_caplan]

Realize there are two temp "senders". One is an alarm temp switch that completes a ground and triggers the high temp alarm, the other is a sensor that has variable resistance that is read by the gauge.

Funny, I don't think I have this one? I wonder if it is on the manifold, I will have a look later today. No wires going to it right?

 

[Horigan]

I would find a wiring diagram for your engine to confirm the configuration. If you don't have access to one, post your engine model and maybe someone can share it, assuming they can get over the server photo linking issue.