A typo correction: The top hose of the solenoid goes to the motor mount and the bottom hose of the solenoid goes to the manifold.

I haven't been able to get to run wires to the solenoid to test as you described yet. I removed the top vacuum hose that goes from the solenoid to the rear engine mount while the car was in gear. The result was the same, no change in vibration. Mind you, it's not that the car shakes widely, but there is a vibration in the steering wheel. In addition, when the ac is on the vibration worsens.

At that point while the car was still in drive, I place the vacuum gauge to the solenoid (top) and there was vacuum (18cu in) but no change in the vibration. When I tested for vacuum the first time the car in park.

Note: I had the CEL on in the car for a while. This is from a previous thread. The error that came up then was the Speed sensor. After I did the test on 3/15/10 with the car in drive I noticed that the CEL had gone out. I checked and the CEL still comes on normally when I start the car but the goes out in a second or two as normal.

Thanks

 

If vacuum vs. no-vacuum on the mount makes no difference, then it seems the mount is bad. No MityVac, but do you have any way to suck on that tube? Does the mount hold suction?

 

I got a MityVac and tested the rear motor mount and it held vacuum. I removed the solenoid to test it with power but I was unsure which prong of the electrical connector is the positive/negative. While I had the solenoid out I notice the top connector (going to the motor mount) was open, that is air could freely move in or out exhaling through the top air filter, while the bottom connector was closed.

Thanks

 

Take the plug that goes to that valve, use your multi-meter to measure continuity to ground from each of the pins. The one that has continuity to ground is (-) & the other one is (+). But actually, I think it doesn't matter - solenoid valves like that don't care about the +/- polarity.

What do you mean the top connector was open? The solenoid valve supposed to behave like this...

When it's NOT energized:
- hose to the mount mount is open to air through the top filter.
- hose to intake manifold is closed.

When the solenoid IS energized:
- 2 hoses (mount & manifold) are connected to each other.

 

The pin furthest away from the locking tab is the (-) (see photo). I ran power to the solenoid and it click as I applied power. While energized by the battery both connectors on the solenoid were open. When the power is removed the lower connector is closed. So then the solenoid and mount are OK?

Thanks

 

When it's energized, both connectors should be open TO EACH OTHER. Not open to the outside. If that's what you meant, I believe that's how the solenoid valve is supposed to work.

Energize the solenoid, plug one port, use the MityVac to suck on the other. It should hold vacuum as long as the other port is plugged.

 

Yes, with power applied both ports of the solenoid were open. I blew air in the hose and felt the air come out of the other port.

As you can see in the photos, I applied power to the solenoid and plugged the other end. Neither port held vacuum while energized. When I removed power only the bottom port held vacuum.

In the MityVac manual it lists a section on testing solenoid vacuum. It says that with power applied that port "B" should hold vacuum. But in my case with power applied neither port held vacuum.

Thanks

 

That sounds like a bad solenoid valve. When it's energized, the bottom port is open creating a vacuum leak for the engine, as well as NOT properly sending the vacuum through the top port to the engine-mount.

I guess it seems a bit strange to fail that way; I'd expect it to fail by not working at all. See if the on-line manual thread (in the DIY section) has anything about V-6 Accords. The Helm book will have a comprehensive test, which I hope should match what you've already done.