duxsi

☝️ Very interesting data and subsequent behavior.

Btw, PSM off did nothing for me.

bokh

is your car PDK? Mine is a manual.

duxsi

It's manual.
What's this PDK you speak of?

Sajan

Will let y'all know monday or tuesday if this is it. Parts are here. Having my tech install it and see.
He will also look at the knock sensor when he is in there.

9.1.1

I have been following this threat and I was curious about this solenoids. Well I decided to take a look at it and after 94,000 miles it looks clean!!!

Sajan

nice! Are you able to do some tests on it? Not sure how…I will have to defer to the experts on testing solenoids

edit: measure ohms, and apply 12v to see/hear click.

9.1.1

I don't have a check engine light so I assume the solenoid works unless there is an upgraded version of it, I don't think anything is going to change..

Sajan

might have missed in the thread..do you have the stumble?

none of us have a check engine light.

Just curious how these things work on the bench.

bokh

It gets better: today I put the key on, turned it(didn’t start the car) turned psm off and back on immediately, started the engine and went for a drive. 0 stumble. 40 miles drive.
This is 100% a software issue. Changing parts is a waste of money if only done for the purpose of fixing this stumble issue. It probably triggers changes in the ecu behavior but only temporarily.
The real fix must by with a ecu flash that Porsche will probably never provide given they don’t even admit the issue and we are talking about an old generation…

squidge

From the diagram above, it looks like it's at the very top of the head/valve cover. Any tips on accessing and replacing it? Curious to see if this replacement works for Sajan long-term.

edit - just saw the video a couple pages back, I was hoping it could be done from underneath but bumper removal makes sense.

Also Sajan, have you tried a throttle pedal yet? Did you ever see datalogs where it looked like the throttle position sensor wasn't accurate?

Sajan

@squidge yup, tried a pedal as suggested by koala and didn't make a diff. same stumble/stutter/tugging/misfire/whatever else the hell you want to call it.
data log from the diff pedal seemed okay.

interesting though that PSM trick is working for some..

PSM off trick, no stumbling
koala
bokh
pfan

PSM off trick, still stumbling..
duxsi
me

duxsi

It seems that I'm supposed to turn PSM off and back on BEFORE starting the engine.
Will try again..

Sajan

oh. I think I turned it off after starting. toggled it off and on during and no diff.

also when I had Piwis plugged in prior to driving for logging..it says PSM and a few other things are in diagnostic mode. So I don’t even know if it’s active.
The lights on cluster are blinking for a few things like hold, PSM ..but as I start driving it turns off except the parking one.

car is with the mechanic right now so I won’t be able to re-test psm workflow.

let us know what you find out.

squidge

I did a 30 minute drive today, toggled PSM off/on after halfway when the car was warmed up. Drove perfectly. Tried multiple amounts of throttle between 2-3k, in multiple gears, always torquey and responsive. Interesting indeed.

I have a PIWIS setup in the works as there’s a couple other unrelated things I want to use it for too. Curious to try some of the same stuff Sajan has.

The first couple posts I saw about PSM from koala and bokh implied the car was running. Someone later on said they did it it while off. In my case, the car was on.

bokh

even better: after doing the psm off/on trick for a week (works both when I do it with the engine running or off), I stopped doing it to see: 2 days without any hesitation. The ecu must have learned (temporarily) something with all the psm on/off switches…