Question here? My temp gauge doesn't work and I need to know what to do to fix it? Problem is the repair manual lists two different sending units for the 300 EFI motor. One is mounted in what is probably the worst location for a sending unit: the underneath the intake manifold near the very back of the block (where you can't reach it). The other sending unit is on the thermostat housing. Question is which one or do both send a signal to the temp gauge. Or what? I want my temp gauge fixed so I don't have to take the thermostat out during the summer months when outside temperatures are in the 100s. Please help anyone who know which one is which?

 

The one for the gauge is the one on the back of the engine, up underneath everything. The one on the top of the thermostat housing is for the computer.

 

Thats what I thought. Is there any way to test the sensor without removing the intake? Its next to impossible for me to reach back there.

 

I think you can test for resistance values from positive to the sensor lead, the sensor changes resistance to ground as the heat changes.

 

How do you test the resistance values and what are the values I should look for? I have a multi-tester, but what should I set it to and what numbers am I looking for?

 

Ohms of resistance, but I'm not sure how much, I'd have to look at my manual...

Does somebody else know right now?

 

Ohms of resistance, but I'm not sure how much, I'd have to look at my manual...

Does somebody else know right now?

 

ya set it to ohms...i wish i hate my book and class notes (we just covered this in class)...i have no idea what value.

 

Yes Ohms...

I'm not sure but...

10 Ohms should point the gauge at H mark
70 Ohms should point the gauge at L mark

Regards;

 

They cost less than 5 bucks, I'd just replace it. Its not very hard if you go underneath to get to it. I replaced mine in about 10 minits.

 

I have my custom guage sender were the CPU sensor was. Will that effect anything? The engine seems to run, but has no highend power, could this be the cause?

 

You've got a carburated setup, right? I don't know how this affects that? Was it computer controlled?

 

Yeah it's carbed and has the little computer thing under the distrubitor.

 

Ya'll are forgetting something. My Engine is EFI, and have a very large and annoying intake manifold in the way of everything. Remember it wraps around from one side of the engine over and across the top of the valve cover to the other side where the air intake hoses are. How do I reach it with the manifold in the way?

 

Go from underneath,

Thats how I changed mine. it took about 10-15 min tops. Just have the new sender ready to stick in right away because you will get bathed in antifreeze.