DNorby

Every so often (not very often) I get some piston slap. Today I got some very loud piston slap and a couple minutes later I got the PSM failure and I limped home. A few minutes later I cranked it up and drove it around the block and the PSM warning did not come on.

Has anyone had any problems with piston slap?

I have a 2017 Base with a MT.

Thanks,

David

mreloc

Piston slap? Do you mean pinging? Are you lugging the engine in too high of a gear for the road speed?

Rennolazine

What octane gas are you using?

DNorby

No, when I started the car I got some unusually loud piston slap and then the yellow PSM warning came on (or is it PMS?). Cranked it up again and the warning did not come on.

DNorby

93 from Costco. It was more aggressive slapping this time.

Rennolazine

Maybe try some top tier (shell etc..) gas then its dealer time...

Jaws1

Costco is "Top Tier". Mine runs perfectly on Costco 91. Dealer time.

Rennolazine

There you have it...

DNorby

The piston slap is not unusual, it just seemed loud this time. Maybe the PSM light was a coincidence. I have driven it some more and things seem fine. If things get worse I will take it in.

mreloc

I think any piston slap is unusual and should be investigated. If it was low octane/crap gas pinging that would explain one possible cause, the only other I can think of is lugging the engine too much. If neither of those conditions exist, something is amiss.

4pipes

GTOWN83

Although unlikely, maybe your injection is running lean.

LavaGTS

Can you post a video or sound clip for reference?

DNorby

The slapping only happens once in a blue moon(only when I crank the motor), there would be no way easy way to get an audio of it. It has happened about 4 or 5 times in the year I have owned it. I have about 6,700 miles on it. If the PSM light comes on again I will take it in and talk to them about the noise. I have heard other people here mention the piston slap, but maybe it is something else.

The noise lasts for a couple of seconds after cranking the motor.

StormRune

I agree with the others that you are likely misdiagnosing the sound. I don't get any sound that could be mistaken for that in my '17 C2S... so such a sound probably is unusual.

Costco gas is Top Tier gas, so at 93 octane that shouldn't be a problem... I use it all of the time in my Porsche.

It seems like something you should take to the dealer to hear/diagnose, before whatever the problem is becomes a bigger one. The PSM failure would have left a diagnostic code that they can pull. It would more likely be something related to that since the timing of the two events seems to be more than coincidental.