Question 270 ohm resistor inline with Coolant Temp Sensor [DME]

[VAE30FTW]

Well today I discovered a resistor on the output wire going to the dme hidden underneath the connector boot. The solder was falling apart and causing intermittent contact so I soldered it up again and it runs very well.

Question is should I remove the resistor or leave it inline?

My start up cranks are longer then they should be [due to lean conditions caused by resistor] however the car runs great once warm.

According to this

http://www.bosch-motorsport.de/pdf/sensors/temperature/NTC_M12.pdf

The resistor fools the ecu and makes it think it's always between 80 - 88 degrees Celsius.

Thoughts?

[jlevie]

There is not supposed to be a resistor there. A resistor in the circuit for the ECT sensor will make the DME think that the engine is colder than it is and thus the DME will run a richer mixture and advance spark timing. If I remember correctly a resistor of that value would make the DME think that the engine is at about 130F when it is really at 190F.

[dnguyen1963]

What's your gas mileage? It must be poor.

[nando]

There is not supposed to be a resistor there. A resistor in the circuit for the ECT sensor will make the DME think that the engine is colder than it is and thus the DME will run a richer mixture and advance spark timing. If I remember correctly a resistor of that value would make the DME think that the engine is at about 130F when it is really at 190F.

depending on how cold, it will actually retard ignition timing.

making it think it's at 130f is definitely not a good idea. remove the resistor.

[VAE30FTW]

Thanks for the input everyone!

I will test the ECT that's in the car to make sure it's running properly. and remove the resistor if it checks out ok. my mpg is around 25-26.1 on a dinan chip and 93 octane.

Should I be seeing better mpg numbers?

[reelizmpro]

Is it stock looking or aftermarket? sounds like one of those ebay resistor /performance mods.

[VAE30FTW]

Is it stock looking or aftermarket? sounds like one of those ebay resistor /performance mods.

Definitely not stock. It looks like slmething you can pick up at radio shack. Just took the 270 ohm resistor out and tested the ect.

At 28 celcius it read 1770 ohms and 243 ohms once up to optimal temperature.

On top of that the car feels much peppier!

Also shouldn't the resistor have been wired in parallel to the two wires to alter the output instead of just spliced into the output wire?

[VAE30FTW]

Here's a pic of the resistor

[jlevie]

Also shouldn't the resistor have been wired in parallel to the two wires to alter the output instead of just spliced into the output wire?

In series is the right way to do it. The higher the resistance of the ECT the colder the engine. So you add resistance to make the DME think the engine is cold and thus it will richen the mixture.