2005 Cayman S (987) engine 'pulsing' noise @ 3500rpm / 90mph
03-08-2015, 07:56 AM
#1
2nd Gear
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2005 Cayman S (987) engine 'pulsing' noise @ 3500rpm / 90mph
Hello there, firstly this is my first post as I keep meaning to join the forum but hadn't really need to post anything until now.
Ive owned my Dec 2005 Cayman S for 12 months and it is fantastic (obviously!) it has covered a mere 35,000 miles in 9.5 years! Full Porsche s/history.
Now, my query is (and I am hoping its a boxer trait) but I have noticed, say down the highway travelling at 90mph (for example) in 6th gear, the revs are quite 'normal' say 3000-4000rpm and I hear a beautiful engine tone - except it sounds a bit unbalanced in the sense there is a 'pulse' every one second.
I have good hearing, and I would say you would need this too to hone in on the engine noise I mention.
Imagine, humming softly every one second on, one second off.
I would assume at a constant RPM the engine noise would be totally flat / the same constant noise - but I can hear like the air inlet induction noise pulsing on/off very softly (as if you tap the pedal every other second really gently in 6th gear doing 90mph)
Hope this is clear. Many thanks for any thoughts
Ive owned my Dec 2005 Cayman S for 12 months and it is fantastic (obviously!) it has covered a mere 35,000 miles in 9.5 years! Full Porsche s/history.
Now, my query is (and I am hoping its a boxer trait) but I have noticed, say down the highway travelling at 90mph (for example) in 6th gear, the revs are quite 'normal' say 3000-4000rpm and I hear a beautiful engine tone - except it sounds a bit unbalanced in the sense there is a 'pulse' every one second.
I have good hearing, and I would say you would need this too to hone in on the engine noise I mention.
Imagine, humming softly every one second on, one second off.
I would assume at a constant RPM the engine noise would be totally flat / the same constant noise - but I can hear like the air inlet induction noise pulsing on/off very softly (as if you tap the pedal every other second really gently in 6th gear doing 90mph)
Hope this is clear. Many thanks for any thoughts
03-09-2015, 12:53 AM
#2
Rennlist Member
Hello and welcome to the forum.
I too have a late 2005 built Cayman S. But it is considered a 2006 model year and not a 2005 as you indicate yours is.
Are you located in the US? If so it is a 2006 (no "2005s" imported).
In other countries, there was a 2005 model.
I have not noticed anything like what you are experiencing.
Is this a new symptom?
Does this only happen when the car is on cruise control, or does it happen when you have your foot firmly on the accelerator pedal?
Are there any other engine running symptoms such as high idle, hunting idle, etc?
What is your fuel mileage like?
Can you check your OBD codes to see if the engine is reporting anything code-wise?
I too have a late 2005 built Cayman S. But it is considered a 2006 model year and not a 2005 as you indicate yours is.
Are you located in the US? If so it is a 2006 (no "2005s" imported).
In other countries, there was a 2005 model.
I have not noticed anything like what you are experiencing.
Is this a new symptom?
Does this only happen when the car is on cruise control, or does it happen when you have your foot firmly on the accelerator pedal?
Are there any other engine running symptoms such as high idle, hunting idle, etc?
What is your fuel mileage like?
Can you check your OBD codes to see if the engine is reporting anything code-wise?
03-16-2015, 04:51 PM
#3
Relatively new here too but I read somewhere (was it Pedro's Garage site?) - about a harmonic vibration somewhere around 3,000 rpms. If recall correctly the suggestion was to avoid cruising at that speed and to either slow down a bit or speed up 
to avoid. However, that is was over a narrow range so if yours is over more of a broad rage of revs, say 3K -4k, perhaps it is the tire balance?
to avoid. However, that is was over a narrow range so if yours is over more of a broad rage of revs, say 3K -4k, perhaps it is the tire balance?