egr rest state?

[BerniniCaCO3]

Just curious, is the "at rest" state of an egr valve, with no vacuum going to it, open or closed?

I have code 31, for the egr.
I like to pamper my car, and knowing that the vacuum line was intact and still pliable, went after hardware: I just did the position sensor, valve, and switch.
Well, the code's still there.

I was feeling the vacuum line and don't know if I feel any vacuum (would you be able feel 15psi with your thumb, over a 1/8" line?) or just engine vibration. The engine ran identically, but, it's a small line.
Can lines clog?
Or that little blue canister built into the vac line, is that a check valve that can stick?

[86VickyLX]

Think about it... If the EGR valve is open, the exhaust gases are being sucked through the intake... Do you want that happening at idle? NO!

You replaced the position sensor? What color is it? What color was the one originally on the car? There are different colored sensors with different readings based on when the valve is open or closed.

The EGR valve is not supposed to open at idle, so you shouldn't have much, if any vacuum on that small line. The only thing you hadn't mentioned was the vacuum regulator. There's two lines going to that. A green one, and a red one. The red one should have manifold vacuum whenever the engine is running. If you have vacuum to that line on the regulator, and no vacuum coming out when the regulator is turned on. Then the regulator is at fault...

[BerniniCaCO3]

The vacuum regulator is new, too (I was calling it the solenoid, which it may be also, as a switch).
There is a clean vacuum line going to the regulator.

Hmm, good point. I just followed the catalog. What is in there now, is grey. I do not know what originally went on a 1990. There was another brand's position sensor that was white. I figured the difference was simply what color dye that manufacturer had for their vat. Is there more?

I may have to start tracking down wiring otherwise. Easiest, if all the 5 wires (2 for the regulator, 3 for the sensor) go straight to the ecm, I'll simply redo all of them from scratch, than play the game of picking through the harness!
It may be that new terminals would help. They're certainly dulled with age/light corrosion, but inside the terminal where it actually contacts, cannot be cleaned by any brush, unless soaking in a rust remover makes any sense.

What I want to be sure of, is that this code does not affect performance (that the egr valve is not open when it should not be!)

[gadget73]

The grey sensor should be proper for a 1990. I don't know what the black sensors were used on, but I have never seen one on a panther.


Should be zero inches (vacuum is measured in inches, not psi) vacuum at idle, and it should max about 8 inches when its supposed to be open. Code 31 means the valve is shutting too far, probably because the pintle is eroded or something, or the sensor isn't sitting right, or maybe because there is a wear dimple on the back side of the valve where the sensor contacts. Check the voltage and see what it has to say.