Hello every one.

just like to know what sensor use the PCM on my 86. to determing the engine temperature.

since my car is showing bad performance when cool engine. but once it get to normal temperature the car work perfect.

so Iam guesing. the pcm is not getting good reading temperature

 

Engine coolant temp sensor is in the front of engine below throttle body. h

 

ok thanks... I know where it is now I remember seen that sensor. now how do I know if the sensor is ok or not . any boby

 

That sensor displays the digital temp...... have you checked your
digital display?

 

You will need a D-VOM (Digital Volt-Ohm Meter) to check the items below. It should have at least a 10 megohms per volt rating---something that will be shown in the specifications.

For those sensors listed below that have ohms listed as the measurement item, disconnect the negative battery terminal and then the sensor harness connector and measure the sensor's terminals.

For voltage measurements, you can obtain test harnesses from any of the Corvette specialty catalog houses.

Before beginning your efforts, print the ECM codes page along with this page so you can cross reference the code information with the sensor information.

Sensor Outputs:

Sensor

Measured Value

Engine Coolant Temperature Sensor. 185 Ohms @ 210F, 3400 Ohms @ 68F, 7,500 Ohms @ 39 F.
Engine Oil Temperature Sensor. 185 Ohms @ 210 F, 3400 Ohms @ 68 F, 7,500 Ohms @39 F.
Oil Pressure Sender/Switch. 1 Ohms @ 0 PSI, 43 Ohms @ 30 PSI, 86 Ohms @ 60 PSI.
Fuel Quantity Sender. 0 Ohms @ Empty, 45 Ohms @ 1/2 Full, 90 Ohms @ Full.
MAT (Manifold Absolute Temperature Sensor). 185 Ohms @ 210 F, 3400 Ohms @ 70 F, 15,000 Ohms @ 40 F.
Outside Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
In Car Temp Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
MAF (Mass Air Flow) Sensor. .4 Volts @ idle, 5 Volts @ Full Throttle.
Oxygen (O2) Sensor. .1 Volt Lean Mixture, .9 Volt Rich Mixture.
TPS (Throttle Position Sensor). .54 Volts Idle, ~ 5 Volts Full Throttle.
Sensor Locations

Sensor

Location

Engine Coolant Temperature Sensor. Front of engine, below Throttle Body.
Engine Oil Temperature Sensor. Left rear of engine, just above the oil filter.
Oil Pressure Sender/Switch. Top, left hand rear of engine.
Fuel Quantity Sender. Top of fuel tank, beneath filler pipe escutcheon panel.
MAT (Manifold Absolute Temperature Sensor). Underside of manifold air plenum at rear.
Outside Temperature Sensor. Right side of engine, top right corner of radiator.
In Car Temp Temperature Sensor. Coupe: above left seat near interior courtesy light, Convertible: center of cargo compartment lid.
MAF (Mass Air Flow) Sensor. Front of engine ahead of throttle body.
Oxygen (O2) Sensor. Left side of engine, in exhaust pipe.
TPS (Throttle Position Sensor). Right side of throttle body at the front.

 

now that you mention I will take a look when I get home. but now the question come up. if this sensor work for the digital dash display only or the tell the pcm the engine temp.
or is use for the 2 things?????

 

The digital sensor 'talks' to the ECM, and displays the temp digitally.

 

ok thanks. I will check temperature on my dash. if that's ok I get back here. and try to find out why the car have bad performance when cool start

 

the one on the front of the engine is for the computer
and the one on the right head back by cylinder #8 is the gauge.
The one on the left front is for the aux cooling fan.

If you have trouble when cold, it is in the open loop condition. see if you can check injectors.
then timing.
I know, you have timed it 40 million times already.
Then go buy a GOOD set of ignition wires.

Just because,
if your car does not run good in open loop, you need to check all the things that are working before the computer goes into closed loop, like the COMPUTER!

 

Have you pulled the engine codes to see if it is showing a CTS fault?

 

The sensor in the front of the intake manifold goes to the ECM ONLY. The sensor in the passenger side head is for the dash temperature gauge.

In later years the ECM sends the temperature to the dash. I think that started with the LT1s.

You can check the CTS with this chart:

 

Thank you all for your help. regarding pulling codes. I never get them. I think my engine light on dash is burn. because it never on. so I will take the car to a mechanic just to read the codes. that will be a good start....

 

open loop condition. I will read more about that.