First Model 3 motor failure reported

[jsmay311]

Is your friend still undecided?

Lol. Actually yes. I was texting with him last night about it and he said "Funny thing is I am still wondering if I should buy one, even after this sickening display" And then he made a joke about Elon really going overboard with the Model 3 anti-selling.

Honestly I was just super glad I was the one in the driver's seat when it happened. I was planning on letting him drive it, and if he had been behind the wheel when it happened I'm sure he would've felt awful.

 

[P85_DA]

Sure... but it's not like I was doing anything out of the ordinary or even mildly abusive with the car, unless you're suggesting Model 3 owners should never try to use the full available acceleration. I guess I fail to see the humor unless someone is abusing their vehicle.

My only real fault was babying it too much up until that point. I actually had it in Chill mode for most of my 63 miles. If I had never tried to "show off" the acceleration, who knows how long I would've been driving around in a defective car without realizing it.

You didn’t mention anything about a power reduced message etc ..which leads me to believe you don’t have a battery or motor issue but more of a cv joint or shaft (mechanical ) also didn’t mention did u hear any type of “milling” noise which is consistent with motor failure

 

[iwannam3]

Model 3 has an oil filter that the S and X don't have. I assume it is from lessons learned on their DU failures and should make the Model 3 DU last longer.

 

[jsmay311]

You didn’t mention anything about a power reduced message etc ..which leads me to believe you don’t have a battery or motor issue but more of a cv joint or shaft (mechanical ) also didn’t mention did u hear any type of “milling” noise which is consistent with motor failure

My experience aligns well with the story from the original post, and that required a new drive unit. And it's clearly not the battery causing the car to violently shake.

And the milling noises associated with earlier Model S drive unit "failures" were from premature wear which caused noise but they were still operable. That failure mode is obviously not what happened here. But I'm sure there are other more catastrophic ways for a motor to fail.

Sounds as if either a CV joint in the axle shaft broke or a drive gear in the motor/transaxle.

I don't think it could be a CV joint or axle shaft. My understanding of an open differential is that even if you totally disconnect one wheel (via a broken CV joint or axle shaft failure on one side), it would still deliver torque to the other wheel, so I don't think that could be the case here. (Also, there weren't 2 separate loud bangs -- just one -- nor any feeling of the car momentarily pulling in one direction, and both sides failing simultaneously seems implausible.)

So I'm thinking it's gotta be upstream from the differential. Which is why I'd love to see a visual of the insides of the drive unit to see what could have possibly failed in there.

Lesson learned, punch it hard in the delivery lot

Haha, yeah. It should be added onto all those Model 3 delivery checklists floating around online.

And to be more specific, get it up to ~20mph before punching it. The acceleration when flooring it from 0mph doesn't throw you back in your seat like it does at 20mph, so I'd think the peak stress on the drivetrain would be less as well.

 

[ulrichw]

[...]
I don't think it could be a CV joint or axle shaft. My understanding of an open differential is that even if you totally disconnect one wheel (via a broken CV joint or axle shaft failure on one side), it would still deliver torque to the other wheel, so I don't think that could be the case here. [...]

This understanding is incorrect - an open differential will deliver a torque to both axles equivalent to the torque on the axle that offers the *least* resistance. (See the section on "Loss of traction" in the wikipedia article: Differential (mechanical device) - Wikipedia)

So if you have no resistance on one axle, the other one receives no torque.

A limited slip differential converts an "open" differential to a semi-locked or locked differential (which has both axles moving at the same speed) - this would tend to force the two axles to move at (close to) the same speed, supplying torque to the axle with more traction.

Tesla simulates this function by using the brake on the wheel with less traction (which will also supply more torque to the opposite wheel), but that obviously will not work if the connection between the differential and the wheel is broken.

 

[JRP3]

My understanding of an open differential is that even if you totally disconnect one wheel (via a broken CV joint or axle shaft failure on one side), it would still deliver torque to the other wheel

No, as ulrichw explained above you basically have this backwards, open diff delivers power to the wheel with least resistance, so a broken joint or shaft would spin freely and the other wheel wouldn't move. One way to get a vehicle to move with a broken CV joint or axle shaft is if you can clamp a vise grip onto the broken part that's still attached to the transaxle and wedge it against something so it can't turn then the other wheel will move the vehicle.

 

[ℬête Noire]

No, as ulrichw explained above you basically have this backwards, open diff delivers power to the wheel with least resistance, so a broken joint or shaft would spin freely and the other wheel wouldn't move. One way to get a vehicle to move with a broken CV joint or axle shaft is if you can clamp a vise grip onto the broken part that's still attached to the transaxle and wedge it against something so it can't turn then the other wheel will move the vehicle.

Unless the joint itself is intact and the free end somehow goes sideways near 90 degrees, wedges/catches on something, and acts like a lever to get jammed. I don't know if this is a viable possibility with how the Model 3 is set up?

 

[jsmay311]

This understanding is incorrect - an open differential will deliver a torque to both axles equivalent to the torque on the axle that offers the *least* resistance. (See the section on "Loss of traction" in the wikipedia article: Differential (mechanical device) - Wikipedia)

So if you have no resistance on one axle, the other one receives no torque.

A limited slip differential converts an "open" differential to a semi-locked or locked differential (which has both axles moving at the same speed) - this would tend to force the two axles to move at (close to) the same speed, supplying torque to the axle with more traction.

Tesla simulates this function by using the brake on the wheel with less traction (which will also supply more torque to the opposite wheel), but that obviously will not work if the connection between the differential and the wheel is broken.

Ah... good point. I should’ve realized that. Thanks for clarifying.

 

[vinnie97]

Just hit the 1k mile point *cries*. I've almost exclusively been pampering it (forgive me, I come from a Prius...). I thought I'd do the aforementioned "punch it at 20 mph" test in light of the early ownership failure reported above. Those poor tires! It passed with flying colors. However, I fell short of actually flooring it. The thought of more (P)ower is unfathomable. Word of mouth is going to be very dangerous to the shorts and those easily led by big oil propaganda.

 

[jsmay311]

I got a call from the local service center earlier this afternoon with an update. They informed me that my car's drive unit would be replaced. Apart from that, the only concrete piece of information about the failure that they had to share was that the pyro fuse had blown. (This fact apparently had been relayed to the SC by Tesla Engineering who had reviewed the vehicle logs.)

Please help me understand this. I thought that if the pyro fuse blows, it isolates the high-voltage battery. But after I heard the initial “bang” from the rear of my car and I lost power to the wheels, the motor appeared to continue to respond to accelerator pedal inputs by revving up (as evidenced by the rear end of the car shaking/shuddering and emitting loud noises after pressing the accelerator pedal on 2 separate occasions, and also by the speed on the speedometer rising up independent of the wheel speed at the same time as the shaking and noise). Additionally, the AC continued to blow cold air for at least another 30 minutes despite 95F outside temps.

If the pyro fuse had actually blown, wouldn’t neither of these things be possible? (I.e., the motor wouldn’t rev up and the A/C compressor wouldn’t run because neither would have any power available to them?)
Or am I misunderstanding what the pyro fuse does?
Or am I grossly misinterpreting some other critical detail? (Which has certainly been known to happen, including as recently as 6 posts ago.)

 

[JRP3]

Sounds as if they aren't telling you the whole story. Pyro fuse makes no sense from your description. I would question them further and request a parts list of replaced items. I think by law you may be able to request the broken parts. Though maybe not if it's warranty work.

 

[TheLocNar]

Love all the whataboutism in this thread, and bringing up bolt failures in an attempt to distract from a Tesla M3 DU failure. People. Stop making excuses.

This "Tesla is perfect/Anyone who posts problems is a TROLL/Short" attitude is why Elon knows he can nickle-and-dime his customers.

 

[TheLocNar]

I got a call from the local service center earlier this afternoon with an update. They informed me that my car's drive unit would be replaced. Apart from that, the only concrete piece of information about the failure that they had to share was that the pyro fuse had blown. (This fact apparently had been relayed to the SC by Tesla Engineering who had reviewed the vehicle logs.)

Please help me understand this. I thought that if the pyro fuse blows, it isolates the high-voltage battery. But after I heard the initial “bang” from the rear of my car and I lost power to the wheels, the motor appeared to continue to respond to accelerator pedal inputs by revving up (as evidenced by the rear end of the car shaking/shuddering and emitting loud noises after pressing the accelerator pedal on 2 separate occasions, and also by the speed on the speedometer rising up independent of the wheel speed at the same time as the shaking and noise). Additionally, the AC continued to blow cold air for at least another 30 minutes despite 95F outside temps.

If the pyro fuse had actually blown, wouldn’t neither of these things be possible? (I.e., the motor wouldn’t rev up and the A/C compressor wouldn’t run because neither would have any power available to them?)
Or am I misunderstanding what the pyro fuse does?
Or am I grossly misinterpreting some other critical detail? (Which has certainly been known to happen, including as recently as 6 posts ago.)

They definitely aren't telling you everything. Sucks, but I hope they get you your car back soon and it's in working order.

 

[jsmay311]

I would question them further and request a parts list of replaced items. I think by law you may be able to request the broken parts. Though maybe not if it's warranty work.

I don't know about any relevant law, but it doesn't seem likely in this case. They said they'd be shipping the old drive unit back to Tesla HQ intact for them to inspect. They aren't even going open up the case to look inside it here at the local service center.

 

[Carl_Drogo]

They pulled over and had to get the car towed to their service center. Service center found out it was a blown motor.

Sounds like that R2 unit just had a bad motivator.

 

[DrMLoveless]

I bought a Ferrari 308 in the 1980s and the one thing I expected was a tough engine (after all the endurance racing etc..)

Within 500 miles I needed a new engine as the original was drinking oil! Freak incident?

I understand that if electric motors last the initial period then they run 'forever'. We used to have brand new electric motors on air conditioning equipment fail within days (or not at all..)

With computers, we used to call this “crib death”, so to avoid it, we would run repeating diags for 3-4 days to weed out PCs prone to die early.

 

[Turbo3]

The drive unit has three gears that give it a 9:1 ratio. (input gear, intermediate gear and output gear)

Not a mechanical engineer but I would guess the intermediate gear failed. They will know when they open the drive unit up back at the factory. All the pieces will be in the drive unit and oil filter so they can see if there was a defect in the gear like a small crack that grew under stress.

It needs to be opened under controlled conditions which is why the SC is not doing it.

 

[BioSehnsucht]

With computers, we used to call this “crib death”, so to avoid it, we would run repeating diags for 3-4 days to weed out PCs prone to die early.

Bathtub curve - Wikipedia

 

[timk225]

We used to have a refrigerator in the basements at my Dad's house, 30+ years and it was still running.

 

[jsmay311]

I got a call from the local service center earlier this afternoon with an update. They informed me that my car's drive unit would be replaced. Apart from that, the only concrete piece of information about the failure that they had to share was that the pyro fuse had blown. (This fact apparently had been relayed to the SC by Tesla Engineering who had reviewed the vehicle logs.)

Please help me understand this. I thought that if the pyro fuse blows, it isolates the high-voltage battery. But after I heard the initial “bang” from the rear of my car and I lost power to the wheels, the motor appeared to continue to respond to accelerator pedal inputs by revving up (as evidenced by the rear end of the car shaking/shuddering and emitting loud noises after pressing the accelerator pedal on 2 separate occasions, and also by the speed on the speedometer rising up independent of the wheel speed at the same time as the shaking and noise). Additionally, the AC continued to blow cold air for at least another 30 minutes despite 95F outside temps.

If the pyro fuse had actually blown, wouldn’t neither of these things be possible? (I.e., the motor wouldn’t rev up and the A/C compressor wouldn’t run because neither would have any power available to them?)
Or am I misunderstanding what the pyro fuse does?
Or am I grossly misinterpreting some other critical detail? (Which has certainly been known to happen, including as recently as 6 posts ago.)

Does anyone else have a better understanding about the effects of a blown pyro fuse and can point out errors in my logic?

I'd much prefer to be corrected on the facts than believe that Tesla was telling me untruths.