Temperature Gremlin

[Szukala]

Boat seems to have a gremlin i need help tracking down. 2000 four winns h200 with 5.0 GI PWTR. At initial startup, temp immediately pegs on dash and high temp alarm goes on. Will stay on for five minutes or so, gauge will bounce around, then eventually drop to normal and dismiss alarm. Then all is well the remainder of the day with later starts. Next time out, same thing.

Just replaced impeller and the temp sender (3850397) located on tstat housing. Boat is NOT getting hot, so had to be a bad sensor somewhere. Is there another sender I'm missing?

 

[alldodge]

Might be a bad ground

 

[Szukala]

Could a ground be affected by temperature? Only seems to be a problem when cold then fine remainder of the day.

 

[alldodge]

If it has a bad ground, it could be heating up and contact improves

That said, most gauges use senders 180 (cold) to 33 (hot) ohms. The gauge is pegging so the gauge wire might be grounding out. If you have European gauges they work in reverse (cold low and hot is high resistance)

The gauge has nothing to do with the ECM, it just a visual for the driver. But with it pegging is tell me something is not right and could be the wiring. For the ECM to sound the alarm, the same issues are effecting its sensor readings