Temp Gauge inop

[TurboSubie]

Will start to move, then goes back to cold..but if I let it sit and idle it will move to normal temp sometimes, then go back to cold. I have antifreeze. maybe a temp sensor?

[vrg3]

When it reads cold, does the heater work? If not, maybe it's a bad thermostat.

It could also be a bad temperature gauge sender. You might try my scan tool; it'll tell you what the ECU's temperature sensor measures (the ECU and the gauge have separate sensors).

[TurboSubie]

where is the temp gauge sender located? the heat works...so im pretty sure this is the problem. any idea on the location.


Thanks,
Eric

[vrg3]

Underneath the intake manifold, there is a water manifold going from the front passenger side corner of the engine to the rear driver side corner. On turbo models, the two sensors are threaded into it near the rear driver side, kind of near where the coolant filler tank is. On non-turbo models, they're over on the passenger side of the water manifold.

The sender for the gauge has a simple spade-type connector. The sensor for the ECU has a brown 2-pin connector.

The gauge sender is part number 21203AA030 and costs like 30 or 40 bucks... if yours is bad you might want to post in the Parts Shed to see if someone can get you a known-good used one cheap.

Maybe the connector is just loose or corroded. I think you can replace it with a regular old 1/4" quick-disconnect.

If you can, I think you should try to verify that the ECU sees correct temperatures. It is plausible that you have some air bubbles or something in the system. Though usually those cause high readings rather than low ones.

[TurboSubie]

I would like to see what my ECU is seeing, don't you need some type of laptop to use the scan tool? I only own a regular PC.

[vrg3]

Yes, you do need a laptop unless you have a reeeeeeally long cord.

But maybe you know someone who has one you could use?

[Legacy777]

The only thing is that...what your ECU sees is different then what you're seeing on the dash gauge.

Just curious....how long has it been doing this? Did you happen to replace a thermostat or change coolant?

here's pics of the sensors
http://www.main.experiencetherave.com:8 ... P_2477.JPG