Effects of having no Water Thermosensor?
 

Hey guys!

While battling some problems with my Turbo II, I noticed that my water thermosensor(WTS) was, and is not, connected. I also realized that it has never been connected since I purchased the car.

I know that the WTS leans out the fuel mixture once the motor reaches 120*, but I am wondering what effect an unplugged WTS will have under operating conditions.

P.S. - I have been searching all day and can not find out any more info.

Thanks!

it will default the computer to HOT all the time. this can cause starting issues. such as not getting enough/ getting too much fuel upon start up

id have to look and see which of these cases are true. when you unplug the sensor the ECU sees this as;

-32F, the ECU will try to supply fuel for this cold of a temp, doubtful the car will even start at a "normal" 65-70F... horrible flooding

or

the ECU will think its HOT, and pull as much fuel as it can. again, it probably won't start at 65-70F, not enough fuel. if you did manage to start it, it will probably be too lean to idle...

in theory the ECU has a fail safe value in the middle (80c), but the ECU tends to just believe the sensor, so it doesn't seem like its smart enough to figure out to use the fail safe.

On my old s5 T2 I had the same situation. I replaced the connector with a good one, re-connected the sensor and voila! Instead of taking about 3 seconds of cranking to start when cold, it only took 1 second of cranking for the motor to start. Hot starts were easier too, no more flooding.

Other than that, I couldn't tell any difference as far as performance at all.

The water thermosensor connector is a Bosch EV1 fuel injector connector with an offset tab, same as s4 BAC valve and same as 88 model fuel injector connectors. You can buy a universal injector connector and use that, as long as you file off the tab from the bottom of the sensor.

or instead of filing off the tab just go to autozone,napa, schucks, or wherever you get parts and buy a new sensor since yours is most likely 20+ years old

I was referring to filing off the tab in the context of replacing the connector. The offset tab connectors don't seem to be widely available. A center tab connector won't work on an offset tab sensor without filing off the tab.

yea i know this. had that issue when i replaced my plug. but on the new one i purchased it didnt come with the tab on it. just the two on the side

oh ok, I guess you didn't get an OEM one from the dealer then. The OEM one says Denso on it and has the tab at the bottom.

The car runs fine when running, just the occasional starting problem when cold. Now I just have to find where that plug wondered off to.....

If i remember right when the coolant temp sensor is unhooked or having probs
doesnt it create rich conditions?