Interfacing a LM335 to a G4 Extreme ECU

[Rod Smart]

Hi, Is, there any configuration details concerning interfacing a LM335 Precision Temperature Sensor to a Link Ecu? previously I was running a Haltech F3 ECU on my Toyota 4AGE with a Scorcher Dizzy. Now with a new set of custom cams and a LinkECU I'd like to retain the previous sensor's I was previously using on this engine. As there are no examples that utilise these sensors, can the internals be configured for pullup's on the analog sensor inputs or would I have to run a resistor from the Reg'd 5V output to the Analog input's that I'll be placing these sensors? these sensors give an output of 10mV/K and operate between -40°C to +100°C

[martin battye]

i think the normal temp inputs have internal pullup.. so you'd need to allocate a 'cal table' and plot your temp vs V to correlate to your LM335 output.

[Rod Smart]

The Temp inputs have a pull-up resistor, but unfortunately, they don't accept the 0-5V output from the LM335 temp sensors, so these sensors must be connected to the Analog inputs, this is not a problem, but I'm asking if the Analog inputs have a pull-up resistor included that can be switched in (internally) or would I have to make a interface PCB to mount some resistors on to?

For me, none of this is really a problem.. just if this ability is already included in the ECU, I won't have to add a piece of strip board in to the case that will contain the ECU.

[ashesman]

I have just had a look over the datasheet for that sensor.  You have a couple of options...  

1 - Add an external pullup resistor between the sensor and +5V Output of the ECU.  connect the sensor signal to an An Volt input.  Set the volt input to ECT - Ext Pullup.

2 - Use the 1k 5V pullup built into a spare temp channel to provide the pullup for the sensor.   Turn that temp channel to Off.  The pullup will still be active.  Wire the signal output to an An Volt channel and set that channel to ECT - Ext Pullup.  This wastes a temp channel but means no external pullup wiring.

Both options will require you to enter a custom calibration.  I would be interested to hear how you get on...

[Rod Smart]

Ok, update on this,

I changed the way I was doing the IAT sensor, I removed the LM335 from the hole I had it in (the same hole used for the cold start injector) and added the Air Temp sensor from a Toyota Corolla 1.8, this sensor was on the air filter box and included a rubber grommet, this grommet is 1mm dia larger than the Injector hole, and the sensor pushes a little tighter into the grommet (will be silicone sealed a bit to verify it seals properly)