Hey guys this question is actually for a 1990 Acura Legend, I know this is an Accord forum and I hate to stick my non-Accord questions in but all the best techs hang out here. Anyway, the engine says Honda all over it.

I am trying to trace a problem that is causing the car to run rich, I first figured out this car has two temp sensors. Here is what I want to know: Can I test a TW sensor easily?? The TW sensor on this crazy car does not control the dash thermometer (I honestly do not know if my Accord does or not). I have tools and am very competent in electronics, can I check the resistance or current or something to see if it is working. I hate throwing parts at the car until something is fixed.

Thanks guys...

 

start the car up and let it warm up till fans come on,,,,,,,turn car off, disconnect plug from tw sensor, measure the resistance between the 2 terminals at tw sensor,, should be 200-400 ohms .......if out of specs replace tw sensor..

to chk the wiring.. turn key on, at the connector chk the red/white wire ( pos) and body ground , should have around 5 volts ..if yes, measure voltage between the 2 wires at connector red/white and green /white . should be around 5 volts ,,,,,,,,,

if any of those voltages are off could be a wiring problem or ecm issue

 

Here's a temperature to resistance chart for em.

 

Now that sounds cool......but for some reason it didn't post.

 

That's pretty normal. On Accords, the TW sensor tells the ECU what the water temperature is. It's got a 2-wire plug. The dashboard guage is driven by a 1-wire sender. Then there's the fan switches... Those systems don't 'share' information with each other.

 

most cars are like that as well, using seperate sensorts for water temp guage and ECU information

 

good catch Jim .. I missed that

the tw ( water temp ) sensor sends signal to ECU on what the coolant temp is at,, this way the ecu can richen or lean the mixture..if tw tells ecu coolant is cold ecu will richen mixture and viceversa

the temp gauge inside the car gets a signal from the sending unit,, like Jim says a single wire unit that will vary resistance with coolant temperature thus will make the gauge move accordingly ...

 

Oh ok, so that is normal. That engine has a lot of oddities so I just assumed that was as well. Still haven't got that sensor checked out, but I will in a day or two.

 

When you do let us know of the outcome of your test, this will help someone out down the road with the same problem as you!

WheelBrokerAng [sm=americanasmiley.gif]

 

oops