solenoid purge valve

hi, i noticed that the valve is tapping at idle speed only, you can hear it right thru the dash board. I unplugged the power to it and tapping sound stopped. Is it on the way to failing. ? Its a 96 tacoma 3.4 4x4 thanks

 

Very common. It's normal. I wrapped my valve with some sound deadening mat to quite it a little bit.

 

Mine just started making a tapping noise too and I've been trying to find the cause of it. I figured it was a vacuum leak somewhere causing it. It's driving me nuts! If you find a solution to this let me know.

 

Do these go bad? Mine looks like new, but just started making the noise intermittently. Seems like it does it most when the engine is hot.

 

I ran the tests specified in the FSM and my VSV is working properly. I wonder if the silicone hose I used on the brake booster gets hot and then loses its rigidity just enough to collapse under the 7 PSI it is subjected to. I'm going to try replacing that hose with one from Toyota next week and I'll report back...

 

The noise is intermittent because the valve cycles when the ecm tells it to. It normally cycles quickly. It's not an on for awhile then off.

 

Think mine is also bad cause I have the slight tapping noise at idle only. Goes away when I slightly press the gas pedal. Been doing it for the last 30000 miles. It is annoying though.

 

Mine never did that until recently when I started replacing the hoses with silicone. The first three I replaced were the brake booster line, the long airbox line and the purge line that connects the throttle body to the VSV. I don't think it's supposed to rapidly click on and off.

 

Ugh, Toyota wants $31 for that small vacuum hose. WTF?

 

Duty Cycle Evaporation (EVAP) Purge Solenoid

The ECM controls vapor flow by operating the duty cycle EVAP purge solenoid. The duty cycle EVAP purge solenoid regulates the rate of vapor flow from the EVAP canister to the throttle body.

During the cold start warm-up period and the hot start time delay, the ECM does not energize the solenoid. When de-energized, no vapors are purged. The ECM de-energizes the solenoid during open loop operation.

The engine enters closed loop operation after it reaches a specified temperature and the time delay ends. During closed loop operation, the engine computer energizes and de-energizes the solenoid approximately 5-10 Times per second, depending upon operating conditions. The engine computer varies the vapor flow rate by changing solenoid pulse width. Pulse width is the amount of time the solenoid energizes. The engine computer adjusts solenoid pulse width based on engine air flow.

 

Turn the sound system up!

If it is broke the OB II will let you know.

 

Thank you for posting this info, Jon. You may be right about it pulsing on and off rapidly, but I still have a feeling something isn't right with my setup. It used to run silently, so I can't easily accept that it's normal behavior. Now when I let off the gas I hear the clicking and the idle sounds rougher for a few seconds when coasting, like a gassy fluttering sound. I'm going to keep tinkering with it.

If anyone else with this issue would like to weigh in, I'd like to hear your take.

 

Thanks for the replies, one said turn the stereo up, well thats true you dont hear it when it and blower are on. Other then that i had to do the following-I have had valve covers leaking for a few years, and when one of the spark plugs were full of oil I figured it was time to fix. I also had water disappearing, my neighbor who is a mechanic said when there is no external signs of a leak and compression is good, its probably the water bypass tube under the lower intake. I tore it down the the valley and there was signs of leaking, and the water water was just boiling off in the valley. I replaced it, and all gaskets all new hoses, a new knock sensor harness that was brittle and crackling and while I was in there I ordered a set of injectors from LC engineering. Other then the annoying tick it purrs like a kitty, and is as peppy.

 

Like any other electrical mechanical device it gets worn it gets noisy .

I have no clue if you can pull things apart and clean it sure does not appear that you can.

If the noise bothers you get a new valve and be done