Strange Solenoide Activation Noise while engine is off

[Beowulf]

Strange Solenoid Activation Noise while engine is off.

I have a strange sound like a solenoid trying to activate while the jeep is off. It comes and goes, but it does not matter how long the jeep has been off. I will go out to the garage and just randomly hear this “Grrrr” sound like something is trying to turn on. I cannot even begin to tell where the sound is coming from. It only last a sub second time frame and never happens close together.

Any idea what this might be?

 

[tomesd]

My Tacoma has a similar sound coming from it periodically after the supercharger install- idk what it is either...

 

[Beowulf]

I'm wondering if it could be a Vacuum pump? I started getting some idle issues after letting off the gas recently as well.

After hearing about your supercharger install my mind went straight to vacuum. Maybe we are having the same issue.

 

[1stDeuce]

I got this one!!! We chased a similar noise down in my friend's '96 4-Runner... It's the vapor recovery system venting through a one way diaphram. His truck does it whenever the temperature changes, even if it hasn't been driven in a long time. It sounds like a buzzing noise, just like a relay buzzing, but it's the vapor recovery, because when we pull off the line from the tank to the canister it relieves pressure or vacuum. If we leave the line unhooked, NO BUZZING!! If we plug it back in, it'll buzz a few hours later if the temperature changes more. If you want to verify that this is what your Jeep is doing, unscrew the gas cap slightly when you pull it into the garage. It won't buzz at all so long as the cap is loose. Note: Don't drive it like this unless you like looking at the Check engine light... It'll set a code for "Large Evap Leak" if the cap is loose.

In short: No worries!
C

 

[BigAl]

Strange Solenoid Activation Noise while engine is off.

I have a strange sound like a solenoid trying to activate while the jeep is off. It comes and goes, but it does not matter how long the jeep has been off. I will go out to the garage and just randomly hear this “Grrrr” sound like something is trying to turn on. I cannot even begin to tell where the sound is coming from. It only last a sub second time frame and never happens close together.

Any idea what this might be?

The fuel pump relay clicks, and the the fuel pump makes a "grrr":sombrero: for a few seconds whe you trun the key. I can't think of reason that it would do that keyless unless you have a short in your starting circuit.