Having a cold start issue ever since I changed the spark plugs on my 91 n/a. It starts up, has a real crappy idle for a few seconds, stumbles, and dies. So I am pretty sure its the water thermo sensor that is causing this problem.
However, I can't find it.
I know its under the alternator, behind the water pump housing, but I just can't see it. I have all the accessories still, could that be why I don't see it? If someone can post a pic of where it is, that'd be great.
Thanks,
-steve

 

it's a green square sensor on the back of the waterpump that fits a bosch (square) style injector connector that is retained with a clip. sorry no pic the sensor have turned a bit brown from age FYI

 

Still can't find it

 

 

Excellent!
Thank you

 

how can that cause that problem??

 

IIRC.... If the thermosensor goes bad, the ECU gets faulty readings off of it resulting in a rich condition when the engine is cold. It's rich anyway when the engine is cold but it's even more so when the thermosensor is giving bad readings.

 

No, it's not rich enough. The thermosensor tells the ECU the water temp. If the ECU gets no reading then it defaults to something like 179 degrees (or something close to that) and it will not send enough fuel to the engine.
It works like a choke on a carbed engine (you guys probably aren't old enough to know what I am talking about). It enrichens the mixture so the car will start easily and run when cold.
Symptoms of a bad thermosensor are hard COLD starting and will not idle when cold.