Water Temp Resistor

[blowndodge]

Some of you know that I'm always looking for new answers to problems some of us have ie; pinging and running too hot.

There are many thoughts and ideas. Gadget's site has some from installing a resistor in the air temp sensor to adjusting the TPS or Throttle Position Sensor. I've done them both.

The TPS adjustment did the most for off idle stalling. I've never had is stall since I adjusted it slightly upward.

I added the 1K ohm resistor which eliminated most of the pinging that happpens with the dog sh*t for premium us unlucky folks have on the west coast.

Lately I flushed the radiator and decided that I will never live nor travel into -35 degree weather. I aborted the standard 50/50 mix of coolant to 70/30 distilled water to Low Tox coolant (same green color). Water is far more effective at removing heat than any other liquid. Since the fan kicks on at 212 anyway the 70/30 mixture I'm running won't boil until 230 degrees so boil over shouldn't be an issue and I still have freeze protection to about Zero to -5. The fan always knocks down the temps, even when it was 110 in Lakewood last year.

All of the above have made a noticeable difference. Today was 99 where I live and the fan only came on twice in stop and go traffic which is a lot less than it did before. Usually in hot weather it was on all the time and cooking my legs..

Today afte thinking about it for a good month or more I thought there was even more I could do to keep my Nomad running cooler and thus stronger. I was thinking with 3 sensors monitoring the ECU I had been thinking about adding a resistor to the water temp sensor.

Here's the logic: I rationalized that of all the sensors the really important sensor "might" be the coolant temp sensor. It could be 20 degrees outside and the air temp sensor would be sending that signal to the ECU. Without a signal that the coolant has warmed up the ECU wouldn't lean out the mixture when the water heated up. In my opinion the temp of the water is a more accurate measurement of the heat of the engine. Without the water temp sensor sending signals that the motor is warmed up and the ECU couldn't know to start leaning out the mixture. It would only be getting a signal from the air temp sensor and it's showing its freezing outside! It need to know the water temp too.

This is what the ECU does when the motor warms up. It senses that and adjusts the mixture accordingly. It could do more like change timing too but I don't believe the timing changes with the temp of the air or the water. If you look at the specs in the manual it lists RPMS only as the controlling initital spark lead and total advance. Troubleshooting shows no sensor malfuction associated to timing issues so I just used reasoning?

Anyway about 2 hours ago I spliced in a 330 ohm resistor into the orange wire coming out of the water temp sensor plug. The manual shows the following resistance values at these water temperatures measured in F:

68 = 2.161-3.112K ohms.

122 = 0.785-1.049K ohms

212 = .207-.253k ohms. Temp when the fan kicks on.

As you can see at the time the fan kicks in is the least resistance value to the water temp sensor.

Adding a .330K ohm resistor will fool the ECU into thinking that the engine is cooler and thus not lean out the mixture as far as it would have at 212F Now the sensor will max out at:

.537 - .583K ohms at 212F . The motor will think the coolant is at about 155 - 175F according to my calculation since the sensor isn't reducing it's value in a linear fashion. In other words the higher the water temp becomes the less and less the resistor value decreases.

The reason I didn't try to "fix" everything with the air temp sensor is that going too far with either sensor will show a "red eye fault" when the motor is cold when first starting up. Both resistors don't put the "start up value" outside the parameters set up in the ECU. I wanted to push all the values in the sensors as close to the max allowed in the manual and not show a fault code.

I ran the bike but didn't go but 5 miles just to see if the fault light would come on and it didn't. Tomorrow is suppose to be super warm again and I will try to make it ping when it's all warmed up and hopefully the water temp resistor is doing it's job!

No worries about the fan not coming on. The water temp sensor that controls when the fan kicks on is located at the bottom of the radiator and is not affected.