What is the current state of the 'engine stumble' issue?
#496
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
☝️ Very interesting data and subsequent behavior.
Btw, PSM off did nothing for me.
Btw, PSM off did nothing for me.
Last edited by duxsi; 07-28-2023 at 03:25 PM.
The following users liked this post:
Sajan (07-28-2023)
#498
#499
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
He will also look at the knock sensor when he is in there.
The following users liked this post:
Sajan (07-28-2023)
#501
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
edit: measure ohms, and apply 12v to see/hear click.
Last edited by Sajan; 07-28-2023 at 11:26 PM.
The following users liked this post:
Sajan (07-29-2023)
#503
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
none of us have a check engine light.
Just curious how these things work on the bench.
#504
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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…
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…
The following users liked this post:
one-rennlist (09-06-2023)
#505
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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?
Last edited by squidge; 07-29-2023 at 05:57 PM.
#506
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
@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
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
Last edited by Sajan; 07-29-2023 at 11:28 PM.
#507
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
@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
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
Will try again..
#508
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
#509
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
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.
Last edited by squidge; 07-30-2023 at 08:03 PM.
The following users liked this post:
Sajan (07-30-2023)
#510
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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…
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…