water temp sensor

[supraman7mgte]

I think I may have found the culprit!
I had a little time today,and pulled the VSV,and as per the TSRM directions and tested it.
No airflow through it with 12v,and no airflow while it was dis-connected.
Part # 25860 vsv $73.20 at Jay Marks...ouch!
Okay,does anyone out there have a good one they can sell me? lol

 

[jetjock]

That would prevent the EGR from working at all. If plumbed correctly there will be vacuum applied to the modulator when there's no 12 volts and no vacuum when there is 12 volts. Put another way EGR operates when the valve is unpowered and the ECU turns the valve on to stop EGR.

After consulting the TCCS manuals I can resolve your earlier question: The ECU prevents EGR operation whenever coolant temp is below 150 degrees so the sensor does effect EGR operation. However since coolant temp is a prerequisite for processing code 71 failure of the sensor will not result in the code being set. That's why the sensor is mentioned in the TSRM section for troubleshooting EGR but not mentioned as a cause for code 71. In that sense I was correct. However since your question was if the sensor effects EGR and not whether it can cause coding I was wrong. I hate it when that happens.

The valve is a fairly common cause of EGR failure. That and carbon deposits. Frankly you went about this the hard way. All you had to do was put a vacuum gage on the line like the book says. In this case you got lucky the valve (assuming you tested it correctly) was bad and needed to come out anyway.

Lastly, if you don't wish to buy a new one and nobody has a used one to sell, it can replaced with a 12 volt miniature industrial three-way for around $20 new. Ebay is one source...

 

[supraman7mgte]

The only lighter side of replacing the EGR and the modulator is that it was about 20 years old and needed replacing anyways(i'll repeat this to myself until I believe it)
and HOPEFULLY my testing of the vsv was correct.Even without voltage going to it,according to the TSRM,there sould be airflow through it which it is not.
Thanks again for all your help,guys!