Could this be a PSM problem?
06-23-2009, 07:30 PM
#16
OK guys, count me as member of the random PSM club.
I have owned three 996 Turbos and one regular 996.
Two of the Turbos have developped this issue. It first happened when I changed from Conti to Michelin tires. I thought maybe the diameters might be off and went back to the old tires. But no luck.
My newest Turbo only has 9,000 miles on it and it first happened the day I bought it at about 8,200 miles on the odo in a 110 mls/h turn. Scared me straight. This was with new dealer installed OEM spec tires.
Today I just brought this problem up with Tom at Lucent. He suggested to clean the debries off the ABS sensors in all four wheel hubs. The sensors are magnettic and may give a bad reading with metallic debries clustered around them.
I have owned three 996 Turbos and one regular 996.
Two of the Turbos have developped this issue. It first happened when I changed from Conti to Michelin tires. I thought maybe the diameters might be off and went back to the old tires. But no luck.
My newest Turbo only has 9,000 miles on it and it first happened the day I bought it at about 8,200 miles on the odo in a 110 mls/h turn. Scared me straight. This was with new dealer installed OEM spec tires.
Today I just brought this problem up with Tom at Lucent. He suggested to clean the debries off the ABS sensors in all four wheel hubs. The sensors are magnettic and may give a bad reading with metallic debries clustered around them.
So sorry to bring up an old thread, I am having the same problem. Lucent cleaned the debris off the sensors and still no joy. Could it be the front tires (just had the rear changed and 4 wheel alignment)? Any help would be appreciated.
06-23-2009, 09:17 PM
#17
Instructor
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Mine only happened while going down hill, when does yours do it? Oddly I haven't had the problem since, but then again I haven't driven that road in awhile either. I'll have to shoot up there and see if it's still doing it when I come down.
06-23-2009, 09:38 PM
#18
Dustin,
Mine does it at really odd times. When I'm in the canyons it happens quite often. I believe it could possibly be one of two things Joe Weinstein is giving me some help and I will post back here after I figure out exactly what the problem is. Basically either tires or a sensor (leaning towards tires as sensors have all been checked)
Mine does it at really odd times. When I'm in the canyons it happens quite often. I believe it could possibly be one of two things Joe Weinstein is giving me some help and I will post back here after I figure out exactly what the problem is. Basically either tires or a sensor (leaning towards tires as sensors have all been checked)
06-24-2009, 11:44 AM
#20
06-24-2009, 12:19 PM
#21
Three Wheelin'
hmm,.... strange. stock size wheels and tires?
have you had your steering angle re set?
I know my psm doesn't like certain sway settings and will act up. but it's a mute issue as my suspension would never be set at the point of the psm acting up. I noticed psm would act up when going too tight on the front and too tight on the rear setting. it's the most happy with med-loose front and med-tight rear settings.
have you had your steering angle re set?
I know my psm doesn't like certain sway settings and will act up. but it's a mute issue as my suspension would never be set at the point of the psm acting up. I noticed psm would act up when going too tight on the front and too tight on the rear setting. it's the most happy with med-loose front and med-tight rear settings.
06-24-2009, 01:29 PM
#22
Still plays with cars.
Lifetime Rennlist
Member
A data point. I had a student with a chipped 996TT. It was raining. Several times on the straight PSM kicked in and it sounded and felt like we were driving on the rumble strips. We weren't. I was concerned about a loose wheel or tire about to fail. All checked out fine. When the track dried the problem went away.
06-24-2009, 02:23 PM
#23
hmm,.... strange. stock size wheels and tires?
have you had your steering angle re set?
I know my psm doesn't like certain sway settings and will act up. but it's a mute issue as my suspension would never be set at the point of the psm acting up. I noticed psm would act up when going too tight on the front and too tight on the rear setting. it's the most happy with med-loose front and med-tight rear settings.
have you had your steering angle re set?
I know my psm doesn't like certain sway settings and will act up. but it's a mute issue as my suspension would never be set at the point of the psm acting up. I noticed psm would act up when going too tight on the front and too tight on the rear setting. it's the most happy with med-loose front and med-tight rear settings.
Michellin PS2 tires
235 40 18
295 30 18
06-25-2009, 09:09 PM
#24
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I have the exact same issue, and there's been a few threads about this exact issue on other forums as well. None have generated any type of resolution or fix.
For me it always occurs on freeway interchange sweepers when I'm driving fast either as I'm gently coming off the brake or when I'm gently rolling onto the thottle. It's definitely very unsettling and a bit scary. If traffic is clear, I can replicate this problem on my commute each day. Now I just turn off the PSM before I drive fast through any fwy interchanges, and there's never a problem.
My 01' did this from the beginning. Even after upgrading the suspension to Techart coilovers and to iForged wheels, it still has the issue.
For me it always occurs on freeway interchange sweepers when I'm driving fast either as I'm gently coming off the brake or when I'm gently rolling onto the thottle. It's definitely very unsettling and a bit scary. If traffic is clear, I can replicate this problem on my commute each day. Now I just turn off the PSM before I drive fast through any fwy interchanges, and there's never a problem.
My 01' did this from the beginning. Even after upgrading the suspension to Techart coilovers and to iForged wheels, it still has the issue.
06-26-2009, 02:40 PM
#27
Rennlist Member
What do the front tires look like both in terms of tread depth and age of the compound? Does it seem possible that fresh rear tires vs. (relatively)old/stale/bald front tires could be contributing to a situation that would trigger PSM? I know the manual warns against have too great a difference between the circumference of the tires.
06-26-2009, 04:54 PM
#28
What do the front tires look like both in terms of tread depth and age of the compound? Does it seem possible that fresh rear tires vs. (relatively)old/stale/bald front tires could be contributing to a situation that would trigger PSM? I know the manual warns against have too great a difference between the circumference of the tires.
06-27-2009, 10:55 PM
#29
Burning Brakes
Have not had the steering angle re set. I will go that route next. The shop that did the alignment says they have never reset a steering angle, they do tons of 996TT alignments? The car did not have the issue before the rear tires were replaced??
Michellin PS2 tires
235 40 18
295 30 18
Michellin PS2 tires
235 40 18
295 30 18
If you have an AWD, this can damage your front differential. Stock tire sizes have a mismatch of 0.1".
Your tires are 0.4" off which causes the diff to rotate at 4 time the speed of normal. (Or 13 revs per mile versus 3 rev/mile)
If you have a GT2 nevermind!
A
