Fuel Pump Noise????
Thread Starter
|
Senior Member
Joined: Dec 2003
Posts: 1,186
Likes: 2
From: Mesa, AZ
Fuel Pump Noise????
With the windows up, stereo off, cruise control on... does anyone ever hear a steady noise at speeds of 60 mph and higher??? The noise I hear sounds like a low pitched humming sound that goes away if you change throttle position. Noisy fuel pump maybe??? Anything that can be done about it??? Thanks for any inputs.
Joined: Jul 2004
Posts: 80
Likes: 0
From: Michigan USA
The exhaust tone?
At sixty you're not hearing the fuel pump, you might hear it when you first turn the key to the on position, but haven't turned it to start yet.
The fuel pump makes a "small electric motor whine" kind of sound.
I work for the world's largest automotive parts manufacturer, and one of the many components I have built is fuel pumps. Believe me, if you can hear the fuel pump at sixty, your car is going to blow up!
Electric fuel pumps maintain max fuel press at all engine speeds, idle to red line.
What fuel isn't used is returned back to the tank.
Matt
At sixty you're not hearing the fuel pump, you might hear it when you first turn the key to the on position, but haven't turned it to start yet.
The fuel pump makes a "small electric motor whine" kind of sound.
I work for the world's largest automotive parts manufacturer, and one of the many components I have built is fuel pumps. Believe me, if you can hear the fuel pump at sixty, your car is going to blow up!
Electric fuel pumps maintain max fuel press at all engine speeds, idle to red line.
What fuel isn't used is returned back to the tank.
Matt
Thread Starter
|
Senior Member
Joined: Dec 2003
Posts: 1,186
Likes: 2
From: Mesa, AZ
Nope, it's not the exhaust note. It seems to be coming from the fuel tank which is in the bulkhead directly behind the seats. The best I can describe the sound is it seems like the hum of snow or truck tires. It goes away when you take the car off of cruise control and accelerate or decel...????
Thought I read somewhere back the SLK has a known history of a having a loud fuel pump or something. Whatever it is it sure is annoying.
Thought I read somewhere back the SLK has a known history of a having a loud fuel pump or something. Whatever it is it sure is annoying.
Joined: Jul 2004
Posts: 80
Likes: 0
From: Michigan USA
Hmmm...
An electric pump shouldn't change it's sound. They're either on or off, the pressure regulator may make a buzzing if it's going bad...
It may have an integral press reg/return...
Now I'm curious, I'll look at the manual and see what I can see!
---------------------
OK, now I'm back.
Our fuel pump and separate press reg are mounted transversly on the crossmember (bottom area of tank bulkhead?).
So, I'm thinking you are most likely hearing the regulator, but I have been wrong before, it very well could be the pump.
Good call!
Since they are both mounted together, you should be able to add a "softer" mount. Something more flexible, to help isolate vibration/noise.
The serv man says that to access the pump & reg all you need to do is disconnect the battery (safety first) and remove the splash guard. (under-body panel)
If you are going to open the fuel system you MUST relieve the system pressure first! 54-61psi fuel spray = blindness, big fireball, ruined day etc...
I don't know how you can trouble shoot this if it only does it when at speed. Maybe you can look at the mount and see if a soft mount is even feasible. It may be as simple as placing a piece of rubber gasket material between the crossmember and the mounting hardware, or between the pump and/or regulator and the hardware, or between the... you get the idea.
I have been a bit curious as to what it looks like under those panels, I just might take a look myself this weekend.
Matt
An electric pump shouldn't change it's sound. They're either on or off, the pressure regulator may make a buzzing if it's going bad...
It may have an integral press reg/return...
Now I'm curious, I'll look at the manual and see what I can see!
---------------------
OK, now I'm back.
Our fuel pump and separate press reg are mounted transversly on the crossmember (bottom area of tank bulkhead?).
So, I'm thinking you are most likely hearing the regulator, but I have been wrong before, it very well could be the pump.
Good call!
Since they are both mounted together, you should be able to add a "softer" mount. Something more flexible, to help isolate vibration/noise.
The serv man says that to access the pump & reg all you need to do is disconnect the battery (safety first) and remove the splash guard. (under-body panel)
If you are going to open the fuel system you MUST relieve the system pressure first! 54-61psi fuel spray = blindness, big fireball, ruined day etc...
I don't know how you can trouble shoot this if it only does it when at speed. Maybe you can look at the mount and see if a soft mount is even feasible. It may be as simple as placing a piece of rubber gasket material between the crossmember and the mounting hardware, or between the pump and/or regulator and the hardware, or between the... you get the idea.
I have been a bit curious as to what it looks like under those panels, I just might take a look myself this weekend.
Matt
Joined: Jul 2004
Posts: 80
Likes: 0
From: Michigan USA
Good luck!
I really hope it's just a bad mount or something.
One of the things we test the newly built fuel pumps for is noise, if it is loud it could be sparking (internally) or overheating.
If it is making more than a quiet whine, the test is stopped and the part failed.
You don't hear about cars bursting into flames that often, I'm not trying to scare you!
When we test, the pump is taken to extremes that it will never see in actual vehicles.
Still, we do have the occasional test stand fire! (So you don't have to!!!)
Matt
*Further disclaimer- We build tens of thousands of pumps each DAY, and we might have 3-4 test stand fires a YEAR.
I really hope it's just a bad mount or something.
One of the things we test the newly built fuel pumps for is noise, if it is loud it could be sparking (internally) or overheating.
If it is making more than a quiet whine, the test is stopped and the part failed.
You don't hear about cars bursting into flames that often, I'm not trying to scare you!
When we test, the pump is taken to extremes that it will never see in actual vehicles.
Still, we do have the occasional test stand fire! (So you don't have to!!!)
Matt
*Further disclaimer- We build tens of thousands of pumps each DAY, and we might have 3-4 test stand fires a YEAR.
Guest
Posts: n/a
One of the times my Crossfire was in the shop, the mechanic had another Crossfire he was working on. He was replacing the rear-end since he said it had started to make noise.
The seats are just in front of the rear end, which is on the otherside of the bulkhead.
Just an thought...
The seats are just in front of the rear end, which is on the otherside of the bulkhead.
Just an thought...
Senior Member
Joined: Mar 2004
Posts: 1,352
Likes: 1
From: Manassas, VA
Originally Posted by cgates
One of the times my Crossfire was in the shop, the mechanic had another Crossfire he was working on. He was replacing the rear-end since he said it had started to make noise.
The seats are just in front of the rear end, which is on the otherside of the bulkhead.
Just an thought...
The seats are just in front of the rear end, which is on the otherside of the bulkhead.
Just an thought...
Banned
Joined: May 2004
Posts: 3,205
Likes: 1
From: port hueneme ca.
M.B. rear end wine light pedal common in M.Bs.Had a new 450SL do it.M.B.told me it was common.They would not replace it unless it got loud.The noise is on a light pedal accelerating around 55-65mph.Let your gas off it goes away.
Thread Starter
|
Senior Member
Joined: Dec 2003
Posts: 1,186
Likes: 2
From: Mesa, AZ
Dan... fist let me begin with a quote from you:
Second, let me thank you for your comments but we are not on the same page.
The rear end "whine" you talk about is from a 30 year old car. I would hope they would of fixed it since then. If you carefully re-read my posts I said the noise I hear sounds like a low pitched humming sound that goes away if you "change" throttle position. There is NO noise when I accelerate or decelerate. I hear the noise only when the cruise control is on and the car is traveling at a steady speed 60-65 mph and higher which is completely opposite of what your talking about.... I think, now you have me confused???
Ouch!!!
Originally Posted by Dan Root
M.B. rear end wine light pedal common in M.Bs.Had a new 450SL do it.M.B.told me it was common.They would not replace it unless it got loud.The noise is on a light pedal accelerating around 55-65mph.Let your gas off it goes away.
The rear end "whine" you talk about is from a 30 year old car. I would hope they would of fixed it since then. If you carefully re-read my posts I said the noise I hear sounds like a low pitched humming sound that goes away if you "change" throttle position. There is NO noise when I accelerate or decelerate. I hear the noise only when the cruise control is on and the car is traveling at a steady speed 60-65 mph and higher which is completely opposite of what your talking about.... I think, now you have me confused???
Ouch!!!
Banned
Joined: May 2004
Posts: 3,205
Likes: 1
From: port hueneme ca.
Throttle meaning pedal.or cruise control light pedal?Light pedal meaning constant speed? I would have hoped that M.B. has changed that too but i can hear rearend noise in alot of new cars.Depends how loud it is how i drive it wether the radio is on alot of things.Good luck ,But if it's the rearend let us know.I'll bet my 2cents it is.I have heard rear end noise in newer MBs and Jags etc.Oh that 30year old car was new when i heard it!And I was pissed then !And they made that model 23years!With different engines.Also since then I've always tried to remember to listen while I test drive any new car or old for rear end wine at constant speed.A friend of mine that imported MBs told me about it first and suggested turning up the radio.I told him that cheaper cars don't wine why does a MB.
ps. This is only a suggestion of what it might be.!!
ps. This is only a suggestion of what it might be.!!
Senior Member
Joined: Mar 2004
Posts: 1,352
Likes: 1
From: Manassas, VA
Originally Posted by Dan Root
Oh if you wondered if I can hear rear end in my XF as you described. YES
ops: :shock: :lol:
Joined: Aug 2004
Posts: 1
Likes: 0
Originally Posted by David Burns
Originally Posted by Dan Root
Oh if you wondered if I can hear rear end in my XF as you described. YES
ops: :shock: :lol:
Senior Member
Joined: May 2004
Posts: 4,094
Likes: 8
From: Charleston, SC
Re: Fuel Pump Noise????
Originally Posted by AZ Outlaws
With the windows up, stereo off, cruise control on...
