Weird buzzing noise behind engine?

[pitchlock]

I've got a strange issue, I have a 91 DE auto that is making a strange noise. It will start but then runs extremely rough and dies. When the ignition is on and the car is off I hear a weird buzzing noise. I think it is coming from behind the engine. Anyone else ever had a problem like this before. I recently changed all the plugs, wires, cap, rotor...basically a whole tune up. I'm pretty sure it's not the fuel pump.

[clss240]

has it started since you did the tune up? is this humming constant? and only whne the car is off with key on?

[pitchlock]

yeah it started right after the tune up, but I even switched everything back to the original in case I got a bad cap, plugs...Yes the buzzing is constant it doesn't stop until the key is turned off. The car will start but runs rough and then dies. If you hold the butterfly open it will stay on.

[clss240]

the butterfly? as in the butterfly valves? maybe the vacuum signal hose running to the butterfly actuator thing is kinked and or broken? i have no idea what the buzzing could be though. and also how do you know it isnt the fuel pump?

[pitchlock]

I forgot about the butterfly valves. I'm pretty sure the fuel pump is fine since it make its normal whine when it primes the system. This buzz is coming from behind the motor and does not stop. I'm thinking it could be one of the IACV-ACC or IACV-FICD solenoid valves sticking.

[pflicht]

I had the same problem with my old SOHC... It was one of the sensors in the back of the motor. I unplugged it and it quit making the noise, but the motor also acted real crappy as well. So I just left the damn sensor plugged in and delt with the buzzing sound. Sorry I'm not good with sensor names....

Also, it could be a "bee" stuck back there somewhere.... just a thought

[pitchlock]

Well I found out that the rough idle was from a brand new, bad spark plug. I still have no idea what the buzzing is though. The car now runs and idles just fine so I guess I'm just going to have to deal with the buzz. I thought the buzzing had something to do with why the car was running rough.