EPR valve question.

[69RT/Chrgr]

Rebuilt my RV2 compressor, and when I done, I hooked it up to a Dewalt drill and spun the compressor. I realized right away that it started to push air out the front the stopped, I checked the rear port and it had no intake. When I removed the EPR valve the compressor seemed to work fine, pulled a good suction on the intake and pushed air out of the front. I am know wondering if the EPR valve is bad. should it be closed at room temp and bench testing? I don't really want to buy one if I have a good one, but I'm not really sure how to test it without putting it in the car and charging it.

And I do plan on using R12, that's why I'm not removing it

Thanks

Duane

[Pete in NH]

Hi ,

The EPR valve( evaporator pressure regulator) is there to maintain a 26 to 28 pound evaporator pressure to keep the evaporator from freezing up. It's basically a spring loaded pressure valve not a temperature controlled valve. You can build a special jig to test them, but you need a controlled source of air pressure and some air pressure gauges.

[69RT/Chrgr]

So if you try to run the compressor statically, it works like the intake side is blocked? I tried to get a description of how it works, and I wondering how you can build pressure if you can pull air into the cylinders. Im not questioning what you are saying, just trying to get my head wrapped around it. Im thinking that it would be trying to do a compression test with a plate bolted in place of a carb.

Thanks

Duane

[Bronzedodge]

The Factory Service Manual has several paragraphs on it I believe.  Chapter 24, Test six, long story short, the EPR should have only a 1-4 psi drop across it.  But everything else has to be correct- the first 5 tests, with a 75* load and an under hood temp of 86* minimum.

http://www.mymopar.com/index.php?pid=109

[69RT/Chrgr]

I found what I suspected, the valve was stuck closed. Took the valve out of what was a known good compressor and installed it in the one I am using. When I spun it this time it was drawing air, and expelling air. Not knowing when it is suppose to be open, I couldn't believe it would be closed completely when you first put it in.

thanks

Duane