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mknox
Well-Known Member
Seems unlikely in my scenario, but there might be multiple issues going on here. Mine was definitely an electrical hum like you'd hear from a utility transformer. It would go away completely when I backed off the accelerator to the point where the power went to zero or into regen. Since the motor would still be spinning at speed (no clutch or torque converter in the Model S), an imbalance in the motor would not explain it for me.
Duckjybe
Member
Yep mine too. But I also get an electrical buzz at 30km at only 5 kw of power which sounds like an arcing connection. I have an appointment Nov. 15 so see what happens. Is yours all good now mknox?
mnx
2018 M3P
How many km's on your car when it started? Mine is still silent (I'm @ ~16,000km)
mnx
2018 M3P
It seems to start at abt 7000 miles. My drivetrain was replaced at that mileage and at 14000 the new one had the same problem, so now I am on the third! I will report back at 21000 miles
Wow. Crazy. I guess I have a "good" one then.
Duckjybe
Member
I'm at 26,000 km but I am not sure when the motor noises started exactly - maybe at 20,000 km (12,000 miles). I remember hearing road noise a while back but thought it was just that.
bsd
Member
mknox
Well-Known Member
I also had the buzz at lower speeds. It was different. Not as loud and at a different frequency than the highway noise. That noise seemed to materialize after the high speed noise became apparent. I suspect it is related.
With the new drivetrain, it is completely silent again at all speeds.
With so many reporting this, I hope it is not going to be a recurring problem. Mine showed up at about 12,000 miles / 20,000 km.
steve841
Active Member
I got a loaner today with 3300 miles and it has this exact issue. Should I be nice and point it out to the SC?
I will definitely know that sound if it shows up on mine.
I will definitely know that sound if it shows up on mine.
Well, I have my car back, with the replaced drivetrain assembly, which fixed the high speed noise issue. I was also told by the service adviser that the problem is related to the imbalance issue with the motor, but he could not provide any additional, more specific information. He did mentioned that it was not the first time that they had to deal with this issue. In fact the SC even happened to have a P85 drivetrain assembly in stock.
The noise in my car did not sound like an electrical hum from a transformer (I am very familiar with the transformer hum that is usually caused by vibration of the individual laminations of the transformer core), but was similar to the mechanical noise of the bearing going bad. This is purely speculative, but I continue to think that this noise is probably related to the premature wear in motor bearings that is causing motor rotor play, especially at higher RPMs and when motor is producing torque.
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mknox
Well-Known Member
Remember that a utility transformer hum will be at 60 Hz while the Model S's variable frequency drive will sound different at different frequencies.
There may be more than one thing going on here, but my issue was definitely an electrical one that I could make come and go at will just by modulating the accelerator.
Duckjybe
Member
I too was experiencing the hum from the drive motor even at 60km/h (37mph) and above. Toronto Service, which was fantastic, replaced the drive assembly and all is silent now! One thing I have noticed (and it could be because I was driving a 60 for a few days) but my p85 seems more powerful now or the accelerator mapping has changed? Now I only have to press the accelerator 1/2 way to get amazing acceleration with traction control kicking in. Anybody else notice this? I was also updated to 5.8 at the same time so maybe that was it? Perhaps I was not getting full P85 acceleration from my previously noisy motor. Too bad I have the snow tires on now which are a bit squirrelly with this seemingly new found torque.
mnx
2018 M3P
FWIW the accelerator pedal was re-mapped in 5.8. IMO (and from what I've seen others say) acceleration is less aggressive (eg. you need to press the pedal farther to get more accel, and you have to lift off the pedal father to get regen). The TC kicking in at 1/2 pedal depression is probably a function of snow tires and colder temps but perhaps your old drive unit wasn't putting out full power anymore, hard to say with certainty.
mknox
Well-Known Member
That's great news. I wonder how many "spare" drive units the SCs are stocking? I didn't even have to wait for mine, yet some parts to fix a rear seatbelt problem are on backorder. I also wonder how many of these things are being replaced and if a design change was made to prevent the problem from recurring. I'd hate to think the problem will come back with my new drive unit, and replacements will only last as long as my warranty.
Duckjybe
Member
Apparently the SC are normally stocking a couple of drive units. Toronto didn't have any at Tranmere but had a P at the brand new location that just opened Monday, so they brought one over. I made sure they were going to be able to get one before I agreed to take my car in. Also service centre manager said in future, once Model E is out there will be service centres all over the place in order to service the number of cars there will be on the road. I really can't believe how quick my car is right now. Wow. The old drive unit must have been lagging. I have also noticed it doesn't stutter as much (if at all) when creeping. Still get squeal on mine and it is unlike the P85+ and 60 I drove that both had more of a whine when accelerating and regenerative braking.
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Can you do a test for me if you get a chance? Press your pedal 1/4 and 1/2 way and report your approximate kWh use. I know it is bit difficult to gauge but ball park would be good.
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Can you do a test for me if you get a chance? Press your pedal 1/4 and 1/2 way and report your approximate kWh use. I know it is bit difficult to gauge but ball park would be good.
The way to find the source of the problem isn't all that much fun. Get a set of vehicle noise detection microphones. Place them in areas where the noise might be coming from. You might need to do several runs to determine the location of the sound source.
Duckjybe
Member
The squeal doesn't bother me as I have had it since day one. When I hear it I know I am really rocketing and can really feel the G forces so I now associate it with pleasure!
bareyb
Active Member
I get the squeal on occasion but most of the time only when I'm flooring it and only once in awhile even then. I really thought it was going to bother me if I had it, but it's not nearly as annoying as it sounded in the videos I had seen.
I did the obligatory 0 to 60 speed runs and raced an Audi and a Camaro the first week or so but I'm driving it much more casually now. I don't like to beat my cars and I honestly don't think these cars have strong enough sway bars and bushings to handle the P85's torque. I'm pretty sensitive to rear end weirdness and I can feel the bushings flexing back and forth when really stomping on it. I took it in to the SC, but they said it was normal. If there's ever a retrofit for the sway bar and bushings (without having to buy the tires and wheels) I'd be all over it. I really do think these cars should come stock with them if they have the P85 motor. Anyway, off topic. I don't have the hum. Just the squeal.
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