B230FT Fuel Mileage

[baggy798]

Do check the resistance of the engine coolant temp sensor like 360beast says. It's under the intake manifold runner number three.

From FAQ:

The resistance values between each of the pins on the sensor and ground, are (by eye from the chart):

32F (0C)-- about 6000 ohms within a range of +/- 10%
68F(20C) -- about 2300 ohms
104F(40C) -- about 1300 ohms
140F(60C) -- about 600 ohms
176F(80C) -- about 300 ohms
212F -- about 190 ohms

[bob12]

Originally Posted by baggy798

Do check the resistance of the engine coolant temp sensor like 360beast says. It's under the intake manifold runner number three.

From FAQ:

The resistance values between each of the pins on the sensor and ground, are (by eye from the chart):

32F (0C)-- about 6000 ohms within a range of +/- 10%
68F(20C) -- about 2300 ohms
104F(40C) -- about 1300 ohms
140F(60C) -- about 600 ohms
176F(80C) -- about 300 ohms
212F -- about 190 ohms

That's quite interesting as the quoted resistances ^^^^ are not unsurprisingly about the same for as those for the single dash coolant temp gauge (+ & - on the sensor and connector terminals).

As the 'back' sensor under No3'ish is dual with separate feeds for the ECU and the EZK with only + on the two sensor/connector terminals and - via the sensor body, I am thinking that by connecting a couple of 200 ohm resistors to the connector plug terminals and earthed separately to the engine/body, you could test the sensor/see what happens. Totally impractical though!

If it were me and I thought this sensor was past its useful lifespan I would just replace the sensor which ain't expensive.

Bob

[RollingThunder]

As has already been said, I'd replace the temp sender that feeds the ECU. If this is permanently reading 'cold' then the ECU will be fuelling it accordingly (rich), which seems to be what is happening.

TBH I'm not sure if an open circuit would return a cold or hot status? If cold, it could be just a bad connection or a broken wire somewhere.

I'm sure you're aware, but just in case, the temperature sensor feeding the ECU is under the 3rd manifold runner.