When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I went and tested every single one of those except the fans.
Noticed something interesting.
First switchover vale, no noise. Cannot hear anything for the switchover valve for heating coolant. EDIT: engine needs to be on for this one.. so ignore this.
I heard it activate/deactivate for next 6 solenoid switchover vales..I could hear the intake manifold one.....the exhaust one.....
then....nothing for acoustic simulator solenoid. strange. even though no noise..it says it was able to set the value ..0 or 100.....so it's "responding" but i don't hear any changes.
camshaft adjustment bank 1 and 2 - no noise but same as the other two...responds.
Valve lift bank 1 and 2 - I can hear it click.
FWIW I drove to my office this morning, lots of stumble. On the way home, I turned off stability control (something I almost never do as my ADHD brain forgets about that button). No stumble.
Only a very short drive today with the s/c off, but I too was stumble free. Very strange, but fingers crossed.
I went and tested every single one of those except the fans.
Noticed something interesting.
First switchover vale, no noise. Cannot hear anything for the switchover valve for heating coolant.
I heard it activate/deactivate for next 6 solenoid switchover vales..I could hear the intake manifold one.....the exhaust one.....
then....nothing for acoustic simulator solenoid. strange. even though no noise..it says it was able to set the value ..0 or 100.....so it's "responding" but i don't hear any changes.
camshaft adjustment bank 1 and 2 - no noise but same as the other two...responds.
Valve lift bank 1 and 2 - I can hear it click.
I am going to chase this camshaft adjustment bank solenoid not making any noise when I test it. I am going to test them again today. Perhaps they run better at higher RPMs which explains why the car has no issue pulling above 4K...
If these solenoids are sticking/not running at optimal rate...this might explain the lack of torque and of course....the stumble.
From the other forum:
Originally Posted by luft911, post: 317322, member: 9330
Brett, There are two different types of cam solenoids on your engine. One controls valve lift and one controls valve timing. There is one of each for each bank. They are controlled by the DME computer and will operate at different conditions, cold start, mid range rpm and high rpm. The main purpose is to add more power and torque at mid range to higher rpm and then go back to normal operation when at idle. One solenoid will change the intake lobe on the cam from base lift to high lift to allow more fuel and air to enter the cylinder while the other solenoid will change the cam timing of the intake camshaft, to cause it to go into "overlap" (intake and exhaust valves are open at the same time) for higher rpm power and torque increase. The cam timing solenoid is the one that I have seen malfunction occasionally. If it sticks in the operating position it will cause the engine to idle like a 60's muscle car with a large cam. Terrible for emissions and idle quality. Not very common but does happen. Hope this answers your question.
Ok I went back out to the car....tested the solenoids again.
Valve lift solenoids - I heard them click off and on.
But here's the interesting part!
Camshaft adjustment solenoid bank 1 ..
I hit Execute to 100%....nothing. no noise...Back to 0%.....nothing.
I did this over and over again and maybe the 8th or 9th time? it CLICKED. then every time after that, it made the noise like the other valve solenoids when I hit execute to 100%.
Same thing happened for bank 2.
I went out for a drive and logged the camshaft adjustment % and I saw some weirdness at the same time the RPM dips at 2200ish and at 2800ish..
I accidentally clicked back and forgot to take a picture. Let me go out and do this again lol
9A110530402 but I'm sure there are a bunch of part numbers that have superceded this.
Triple check and make sure it fits your model.
This is the solenoid/actuator in question. I don't think anyone has replaced this yet.
Throttle Control Element - Remark: NVS
SKU:9A1-105-304-05
Description: Variable Cam Timing. Incl.Oil Control Valve.
Replaces:9A1-105-304-03, 9A1-105-304-04
Remove hydraulic valves for camshaft control.
→ 153719 REMOVING AND INSTALLING SOLENOID HYDRAULIC VALVE FOR CAMSHAFT CONTROL .
Here's the other solenoid. This is the one near the coil/plugs that others have replaced with not much luck. Porsche calls this one throttle control element also in the parts catalog program.
SKU: 9A1-105-308-03
Other Names: Control Valve Solenoid, Actuator
Description: Throttle control element. Replaces:9A1-105-308-02
Remove hydraulic valves for valve lift switchover.
→ WM 155519 REMOVING AND INSTALLING SOLENOID HYDRAULIC VALVE FOR VALVE LIFT ADJUSTMENT .
Other part of this equation is the camshaft sensor which probably is the next thing I would chase down.
Engine Camshaft Position Sensor
Product ID: 997-606-106-03
i have a 13 4S 7MT and have a bit of the hesitation. I tried this trick on 3 commutes and it worked perfectly. 0 hesitation. The car was perfect. I even drove with PSM off for 1 minute (hesitation immediately goes away) then turned it on again and the hesitation didn’t come back.
I’ll keep testing this…
btw another thing I noticed that I didn’t know about: when in sport plus and psm is off, rev matching is off. Is it the normal behavior (for safety)?
Originally Posted by koala
FWIW I drove to my office this morning, lots of stumble. On the way home, I turned off stability control (something I almost never do as my ADHD brain forgets about that button). No stumble.
i have a 13 4S 7MT and have a bit of the hesitation. I tried this trick on 3 commutes and it worked perfectly. 0 hesitation. The car was perfect. I even drove with PSM off for 1 minute (hesitation immediately goes away) then turned it on again and the hesitation didn’t come back.
I’ll keep testing this…
btw another thing I noticed that I didn’t know about: when in sport plus and psm is off, rev matching is off. Is it the normal behavior (for safety)?
i have a 13 4S 7MT and have a bit of the hesitation. I tried this trick on 3 commutes and it worked perfectly. 0 hesitation. The car was perfect. I even drove with PSM off for 1 minute (hesitation immediately goes away) then turned it on again and the hesitation didn’t come back.
I’ll keep testing this…
btw another thing I noticed that I didn’t know about: when in sport plus and psm is off, rev matching is off. Is it the normal behavior (for safety)?
Had the exact same experience during a long drive today. There's evidently some type of reset going on which fixes the stumble even after re-engaging the PSM (similar to how disconnecting the battery seems to fix it for maybe a day).
As the PSM has some throttle as well as braking functions, I guess it's possible that some bad coding could be the culprit. I'm curious how PCNA would react if you could demonstrate this behavior.
Here are the logs with PEDAL + RPM + CAMSHAFT ACTUATOR/SOLENOIDS %.
data point #1...the graphs: when torque is requested, these should be going to 100% and staying there for a bit...and they do sometimes and in those instances the RPM graph is linear. the solenoid % is flat at 100%...
But in the scenarios where the RPM dips, these are being erratic. values dropping off to 0% then to 100% and back to 0% etc..
these solenoids are not responding the way the DME wants it to.
data point #2: it takes me 10 times or so on the drive link tests for these to finally come alive and respond to the commands.
07-25-2023, 09:32 PM
