Temp problems

[WB23]

Hello all,
Just outta curiosity, how many different sensors/instruments take temperature and can effect engine performance? 98 Chevy Silverado, 5.0 Vortec.

 

[RichLo]

Well, thats a pretty important sensor, if its not working your engine will always be in open loop meaning t s running off a program rather than taking info from all of the other sensors and optimizing.

So to answer your question about what other sensors are effected by the temp sensor... All of them.

 

[someotherguy]

I read it that OP is wondering how many different sensors are involved in measuring temperature and can affect how the engine runs. Two, on a Vortec. IAT (inlet air temperature) which is on the air intake tube, and CTS (coolant temperature sensor) which is on the intake manifold near the thermostat.

Richard

 

[stutaeng]

I took the question also a @someotherguy. Then there's also the temperature sender in the head of cyl. #1, which is wired directly to the instrument cluster guage, and seemingly is not even seen by the ECU?

 

[someotherguy]

I took the question also a @someotherguy. Then there's also the temperature sender in the head of cyl. #1, which is wired directly to the instrument cluster guage, and seemingly is not even seen by the ECU?

Correct, no consequence to how the engine operates. It's just the dash gauge sender.

Richard

 

[Jason Glover]

Mi e is a 93 K3500 7.4L, and I have one in my passenger side head, similarly located the same as the driver side. So, 1 driver side head, 1 near thermostat, and one in passenger head that I can’t figure out if it’s a temp sensor or temp switch, and where to get the replacement for it.

 

[someotherguy]

Mi e is a 93 K3500 7.4L, and I have one in my passenger side head, similarly located the same as the driver side. So, 1 driver side head, 1 near thermostat, and one in passenger head that I can’t figure out if it’s a temp sensor or temp switch, and where to get the replacement for it.

Your setup is a little different than the original poster - he has a Vortec small block.

On your TBI big block, the one in the intake near the thermostat is for the computer input. This is the only sensor on your TBI engine that tells the computer the coolant temperature.

The one on the driver's side head is for the dash gauge.

The one on the passenger side head is for the auxiliary fan that should be mounted ahead of the A/C condensor.

(By the way the Vortec big blocks are pretty much set up the same way though they have the IAT of course in the air intake tube.)

You must be registered for see images attach

Richard

 

[Jason Glover]

Your setup is a little different than the original poster - he has a Vortec small block.

On your TBI big block, the one in the intake near the thermostat is for the computer input. This is the only sensor on your TBI engine that tells the computer the coolant temperature.

The one on the driver's side head is for the dash gauge.

The one on the passenger side head is for the auxiliary fan that should be mounted ahead of the A/C condensor.

(By the way the Vortec big blocks are pretty much set up the same way though they have the IAT of course in the air intake tube.)

You must be registered for see images attach

Richard

Thanks for the info! I’ve gotta ask, should the sensors be the same identical part? As far as I can tell, the connectors look pretty close to the same.

 

[someotherguy]

Thanks for the info! I’ve gotta ask, should the sensors be the same identical part? As far as I can tell, the connectors look pretty close to the same.

Generally no.. the sender in the driver side head is going to indicate a full range of temperature for the dash gauge, while the one in the passenger side head is likely just a switch that goes on at a certain temperature and back off at another. Typically in parts lists they are referred to as a temperature switch or fan switch. It gets confusing looking them up as well because the connector cavity design changed around 1994 model and the older design has become obsolete/difficult to find. The new connector has an oval shape with room for 2 pins but you'll find the dash gauge sender and the aux fan switch still have just 1 pin populated inside. The coolant temperature sensor (CTS, or ECT) has that same connector design but both pins populated.

Richard

 

[Volunteer454]

Thanks for the info! I’ve gotta ask, should the sensors be the same identical part? As far as I can tell, the connectors look pretty close to the same.

Passenger head:

Engine Cooling Fan Switch Right ACDelco GM Original Equipment 15-4457

Drivers side head:

ACDelco GM Original Equipment 213-78 Engine Coolant Temperature Sensor​

Edit: To clarify, these are the parts for the 1991-1995 trucks with 454 tbi (L19) engines. Most autopart stores only list the sensor by the thermostat. I wanted to share this for someone else who needs to replace these parts, as it took a lot of error and guesswork to find the correct parts. I have been informed the RVs with the same engine may have used a different fan switch, but I cannot confirm that.