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Discussion Starter · #1 · (Edited)
Any ideas on what might be the cause of a recently begun rhythmic pumping sound while driving? This appears to be coming from the rear (backseat?) area and started about a month ago. I just had a Haldex service completed, but that does not make a difference. Could the fuel pump be the cause? Note: Everything else seems to be working fine, no issues while driving, even under hard acceleration, just a slightly annoying "pumping" sound that seems to have a 1/2 to 1 second cycle time. Note: Running Unitronics Stage 1+ software on 93 Octane. Any advice is welcome. Thanks!
 

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This may be completely out to lunch, but...
Under some conditions with the right background noise, I can hear a pulsation in tune with my heart rate. I.e., the variation in blood pressure in my ears makes certain sound frequencies pulsate, similar to what you are hearing. I never heard that sort of thing until I was over 60YO. Maybe you are experiencing that.
 

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Discussion Starter · #3 ·
Dave, thanks for the idea.... but I don't believe that is the issue.... while I am an old guy (probably older than you)...this is pretty much definitely not in that category...I am a retired nuclear submariner, so I am pretty sure I know the difference between Hydraulic/Numatic/other sounds and noises. That said, thanks for the response Dave, but I believe I can pretty much rule that one out currently. However, to everyone else, don't let my reply stop others from sending suggestions, as this one is a real puzzlement to me at the moment.
 

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:) I've been driving cars, racecars, etc., for over 60 years (I'm 79.5 YO), and I know what things sound like. But I had an experience early on with our 2005 Focus that made me aware of what I posted above. I was "hearing" a pulsing sound from the engine compartment that I was absolutely sure was a pulsating exhaust leak in tune with the engine idle speed.

I was so convinced there was an issue that I took it into the dealer service department, and after driving around with the service writer he said (in different words) that he thought I was nuts. Turned out it was my ears' blood pressure that was causing it, and I started hearing it with other sounds. Up till then, my hearing was flawless, and is still very good, but now I'm aware of that and know it's not real. I'm not saying for sure you have that issue, but I did, and it sure sounded real.
 

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Discussion Starter · #6 ·
Spacecowboy,... good suggestion,...I'll try to capture it on my iPhone and see if it has some relationship to something else that is going on, however;.... it does not seem to be speed-related, which is part of my conundrum about this issue. Plus, it is not a full-time issue, as it comes and goes, (seemingly related to road surfaces?) which makes it even more difficult to nail down...yeah, I know that sounds crazy... but that seems to be what is happening. It seems to react differently to various road conditions in that some road surfaces seem to bring it out more than others, but I have not yet been able to identify the differences. I checked the tires (same ones I had for several years before this started) and they seem to be fine... pressure and tread wear are well within tolerance... Also, I just had a physical and came out 100%, so hopefully, that is not the issue...even though I am an old guy... 72 in June...Owner of 50+ cars/trucks/motorcycles in the US and Europe, and counting.... Retired Navy electronics officer, Submarine Combat Control supervisor, Submarine Sonar supervisor, 30 years in civilian IT systems, etc... you get the idea..., So, Dave, while I am not older than you, and not opposed to the possibility of believing that old age may be a part of this, I will need to be convinced of that first, as there are no other indicators of that at the moment! ... and hopefully it stays that way! 😉 😁
 

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Old age, at least in some respects, is just a number. I am still the mechanic, driver, and engineer for my F2000 formula car which I race competitively in the Formula Race Promotions F2000 Championship Series. We have a race the weekend of April 28-May 1 at Mid-Ohio and I'm in the process of final prep on the car now. Good to hear you feel the same way.
 

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Discussion Starter · #8 ·
Dave, you bet I feel the same way!!! Keep on being the guy you are and forget that "age" crap!!! PS.. It's great to hear that others in (my, our) generation feel like that!
 

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Discussion Starter · #9 ·
Update: After some more analysis and driving on some newly paved road surfaces, I will say that I think the tires and various road surfaces are the cause of the sound. (This might also explain the rhythmic component of the sound) I was not able to get a recording of the sound, as it is too faint to be able to pick it out of the just general driving/road noises. I'll update later if my option changes. Thanks to all for your input!
 
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