CHT sensor extension, Curious, does it work? Who uses one? Options

[malcolm2]

I want to cover all my bases here. I have purchased the new GB CHT sensor from 914Rubber to try.

So, I think I will buy a spacer from Brad Mayeur to have the option. From what he says it should:

"Porsche 914/4 Cylinder Head Temperature Sensor Extension.

This little device slows down the heating of the sensor and improves warm up drivability."

I do have "warm up drivability" problems = Low idle RPM until the VDO CHT hits about 250*F. So it seems like my problems don't need the warm up to slow down, it needs to SPEED UP. (IMG:style_emoticons/default/WTF.gif)

914LTD.com





Also found on RATWELL (scroll down to WORKAROUNDS)http://www.ratwell.com/technical/TempSensorII.html#parts

[pbanders]

OK, I can't stop, here's one more circuit where I've added a test node and an isolation switch, so that you can test either the voltage across the CHT and series/parallel circuit, or by opening the switch, test the resistance to ground. Obviously, when the Isolate switch is opened, the car won't run because the ECU will see an open for the CHT, but you can test the resistance so that you know what the setpoint is. While the car is running, you can watch the voltage and see how it's changing as the temperature changes the resistance of the CHT or you change the adjustments on the pots and DPDT switch. Note I have the CHT at 50 ohms, that's just the approximate resistance of the CHT when the car is fully warmed-up.



SPST Switch

http://www.parts-express.com/spst-mini-pad...switch--060-532

Banana Binding Post (red, buy 2: ECU, Test Point)

http://www.parts-express.com/binding-post-red--090-485

Banana Binding Post (black, buy 2: CHT, ground)

http://www.parts-express.com/parts-express...-black--090-480

Banana Plug (red, buy 2: ECU, Test Point)

http://www.parts-express.com/parts-express...ug-red--090-465

Banana Plug (black, buy 2: CHT, ground)

http://www.parts-express.com/parts-express...-black--090-460

Project box

http://www.parts-express.com/hammond-1591a...97-083--320-702

Pot Knobs

https://smile.amazon.com/gp/product/B00NN6M...=UTF8&psc=1

[Spoke]

OK, I can't stop

I know the feeling. Here's a little spin on your updated circuit to have a rich, lean, and normal setting. Using all the same components as you did except using a center off DPDT switch.

When SW1 is in the up position, the CHT is set for lean operation. In the center (OFF) position, the CHT is set for rich operation. In the down position, the CHT is normal.

DPDT Switch ON-OFF-ON

[pbanders]

OK, I can't stop

I know the feeling. Here's a little spin on your updated circuit to have a rich, lean, and normal setting. Using all the same components as you did except using a center off DPDT switch.

When SW1 is in the up position, the CHT is set for lean operation. In the center (OFF) position, the CHT is set for rich operation. In the down position, the CHT is normal.

DPDT Switch ON-OFF-ON

Good idea, I didn't know such a switch existed! You can do the same with mine by adjusting the rich pot to be a shunt, but this is better.