Noise from engine
Discussion
Yes, I know... the engine is supposed to make a noise !
I don't recall this noise being present before, however. The noise is a gentle humming from somewhere at the front of the engine, probably between the 'V'. The noise is constant, only present when the ignition is in the 'on' position (ignition on, engine stopped) and remains when the key is turned to the 'off' position and stops when the key is withdrawn. The noise is probably less than a quarter as loud as the fuel pump noise. The noise is nowhere near the re-circ pump for the heat soak routine. It is definitely at the front of the engine.
The ambient temperature is about 25 degrees Celcius and the car is a '97 V8
Any ideas or suggestions ?
This is going to turn out to be something really embarassingly simple and obvious, isn't it ?...I hope !!
I don't recall this noise being present before, however. The noise is a gentle humming from somewhere at the front of the engine, probably between the 'V'. The noise is constant, only present when the ignition is in the 'on' position (ignition on, engine stopped) and remains when the key is turned to the 'off' position and stops when the key is withdrawn. The noise is probably less than a quarter as loud as the fuel pump noise. The noise is nowhere near the re-circ pump for the heat soak routine. It is definitely at the front of the engine.
The ambient temperature is about 25 degrees Celcius and the car is a '97 V8
Any ideas or suggestions ?
This is going to turn out to be something really embarassingly simple and obvious, isn't it ?...I hope !!
BTW, the V8 doesn´t have a VAC-pump !!!
Between the V there is only one thing that is able to make an almost unaudible noise, its the TPS-stepper motor. However, this one is not supposed to produce a continous noise. ;o/
Thats very strange !
Marcus
www.PUKesprit.de
Between the V there is only one thing that is able to make an almost unaudible noise, its the TPS-stepper motor. However, this one is not supposed to produce a continous noise. ;o/
Thats very strange !
Marcus
www.PUKesprit.de
Not up on the V8... but have you def. ruled out the fuel pump? I know that on my 4 pot (88 S car), the secondary fuel pump started humming much like you described (key on/ motor off/ or just turning key to stop motor but key in 1st position). Turned out to be a relay playing out. Did not seem to be a driving problem and took me a bit to get around to the fuel pump as the sound seemed to be comming more from the front of the motor as well...
Def. get a stethescope from the local auto store... you will find it eventually...
Drive topless!!!
Cameron
Def. get a stethescope from the local auto store... you will find it eventually...
Drive topless!!!
Cameron
Right, tried the stethoscope (use one every day at work) with a tube on the end but it didn't help.
Where is secondary fuel pump and which relay is it so I could pull it (or the fuse) to see if this is the cause
I think it does have an emissions pump (is that anything to do with the pump in the rear luggage bay ?)
What is TPS stepper motor
Where is secondary fuel pump and which relay is it so I could pull it (or the fuse) to see if this is the cause
I think it does have an emissions pump (is that anything to do with the pump in the rear luggage bay ?)
What is TPS stepper motor
Edited by toyroom on Thursday 22 June 21:57
Try shoving a steel rod into the tube of your stethescope and actually touch it to parts of the motor (non moving parts). it is suprizing how sound travels around in the motor.
As for fuel pump locations and relays... I am not up on the V8 so I cannot be sure on your car, but, on the 4 pot cars I have been privy to, the fuel pumps are located just in front of the right side rear wheel- or just behind the sill air duct inlet.
They are easy to see from under the car and quietly hum when operating. IF you have a sticky relay issue, the pump continues to try and run when it should not, increasing the volume of the hum (not loud to begin with). The bracket that holds the pump is bolted to the car in a way that trasmits sound everywhere.
Oh right.. the relay... Not to beat a dead horse here, but again... not sure about the V8... but there are 2 fuel pump relays in the electrical box (ignition box) along with two 15amp fuses. Each pump has its own relay and fuse - so as a test you can swap them around and see if the sound changes?
If your car has been fitted with an undertray, you may have to remove it to get to the fuel pumps...
Drive topless!!!
Cameron
As for fuel pump locations and relays... I am not up on the V8 so I cannot be sure on your car, but, on the 4 pot cars I have been privy to, the fuel pumps are located just in front of the right side rear wheel- or just behind the sill air duct inlet.
They are easy to see from under the car and quietly hum when operating. IF you have a sticky relay issue, the pump continues to try and run when it should not, increasing the volume of the hum (not loud to begin with). The bracket that holds the pump is bolted to the car in a way that trasmits sound everywhere.
Oh right.. the relay... Not to beat a dead horse here, but again... not sure about the V8... but there are 2 fuel pump relays in the electrical box (ignition box) along with two 15amp fuses. Each pump has its own relay and fuse - so as a test you can swap them around and see if the sound changes?
If your car has been fitted with an undertray, you may have to remove it to get to the fuel pumps...
Drive topless!!!
Cameron
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