996 Hesitation between 1600-2200 RPM
12-21-2005, 12:24 AM
#16
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Steve...I am curious if your problem got fixed? I am in Hong Kong now and I drive a 2000 c2. Same problem. So the cleaning of the MAF cleared out the problem? Can you describe your problem as there is 'hesitation' from 1500rpm...then when u press on the gas the rpm jumps to 2000 but then seems like no gear is being engaged....then suddenly the gear kicks in and the car just jumped to the front? That is my problem....very dangerous when in a traffic jam....suddenly it will accelerate more than needed... 
04-17-2019, 08:17 PM
#20
Rennlist Member
If you have a Tip like the OP, then test the transmission for fault codes for torque converter clutch, common problem. Also there is some new repair pieces for the ZF Tip, an improved pressure regulator that replaces/repairs worn out valve body bore for pressure regulator.
05-19-2019, 01:59 AM
#21
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That's the problem I'm running into as well but this is the best I can describe itHey. I have a 1999 Porsche 996 Carrera 3.4l tiptronic and been having issues with accelerating up when I I'm on third gear cause then it makes this spitting sound from the passenger rear and loses 1500-2100 RPMs but still accelerating up but goes back down and up but still increasing speed but RPMs fluctuating up and down until I hit 61 mph it stops fluctuating and making those spitting kinda sounds. But behind passenger side catalytic converter. There is a wire or pipe with oil/dirt/sludge on it. So i know I'm losing oil as well cause I've had to stop it off on the dipstick already 3 times since my last pilot change at 92k and I have 96k now. What problems could it be?
05-19-2019, 05:37 AM
#22
Three Wheelin'
There are spray MAF cleaners available at most auto parts stores.. Like carb cleaner without chemicals that can hurt a maf..
If the MAF doesn't help, a worn TPS sensor will raise hell with drivability.
If the MAF doesn't help, a worn TPS sensor will raise hell with drivability.
05-19-2019, 08:49 AM
#23
Finally, last night, I overcame my hesitation problem, however, it's not as low-dwon the rev range as yours, mine happened under full load at about 2500 thro' to 5000'ish. It manifested itself as jerky acceleration, almost like I would describe a VTEC or harsh VarioCam kicking-in would feel like if you didn't know better. Of course, it wasn't pulling as hard as it should either. Idle also felt "weird", in that if you come up to a junction, dip the clutch, revs would soar up to 1400 for about 5/6 secs, then eventually drop back to a normal idle of 800rpm.
My usual Indy specialist ran PSTII diags on the car and came to the conclusion it was down to the two Lamda sensors (mine is a '98 C2 Manual)...which sounded plausible, as my Subaru's Lamda went at similar age....they all do. £430 lighter, and the prob is still there!!
Spoke to another dealer who suggested it's *probably* the Mass Air Flow (MAF) sensor, as this item doesn't log an error code, instead the Lamda tries to compensate (over compensate), runs out of range, then trips an error code to be logged.
Replaced it last night myself (friend works for Bosch, got me one for £89, versus Indy Specialist who wanted £395+Tax, plus 0.5hr fitting!!!)...Hey Presto, prob gone and I've got my old Porsche back again, and it feels SOOOOO much different!
MAF is by far the easiest and cheapes item to try replacing, all you need is a security torx bit (one with a dimple hole in middle of star) to remove the 2 screws holding it in, gentle pull to break rubber O-ring seal, and it's out. You can't see anything (hot film type, not an element), but somebody on here suggested it can be cleaned and replaced.
Hope this helps,
Spen
My usual Indy specialist ran PSTII diags on the car and came to the conclusion it was down to the two Lamda sensors (mine is a '98 C2 Manual)...which sounded plausible, as my Subaru's Lamda went at similar age....they all do. £430 lighter, and the prob is still there!!
Spoke to another dealer who suggested it's *probably* the Mass Air Flow (MAF) sensor, as this item doesn't log an error code, instead the Lamda tries to compensate (over compensate), runs out of range, then trips an error code to be logged.
Replaced it last night myself (friend works for Bosch, got me one for £89, versus Indy Specialist who wanted £395+Tax, plus 0.5hr fitting!!!)...Hey Presto, prob gone and I've got my old Porsche back again, and it feels SOOOOO much different!
MAF is by far the easiest and cheapes item to try replacing, all you need is a security torx bit (one with a dimple hole in middle of star) to remove the 2 screws holding it in, gentle pull to break rubber O-ring seal, and it's out. You can't see anything (hot film type, not an element), but somebody on here suggested it can be cleaned and replaced.
Hope this helps,
Spen
12-03-2019, 04:51 AM
#24
I have a 99 996 with a Tiptronic and when cruising steady around 1600-2200 RPM the car hesitates and I can watch the tach vary between 50-200 RPM, it is very annoying. The Porsche dealer verified the problem when driving uphill, but it did not appear to exist when going downhill. They suggested I buy 2 front tires to match the Michelins I have in the rear. I put new tires on, but it did not help. Next they want to change the fluid and inspect the transmission for problems. Has anyone else experienced this problem because our local dealer admits they have never heard or seen of this problem before but feel the torque converter may be to blame? Their only option is to replace the entire transmission if the inspection looks good visually. Does anyone have another suggestion?
I have exactly the same problem 997 c2s tip s.
I cleaned the MAF - didn't help
I cleaned the throttle house - didn't help
Fault scanning - No faults
I replaced bmc air filter + silicone housing - didn't help
The spark plugs were replaced with NGK about 4 years ago / 35 K.
I am considering replacing new Bosch OEM spark plugs soon, but at the same time, I do not believe this is the source of the problem.
in brief. What do you advise me? I'm very frustrated.
Thanks
12-03-2019, 07:27 PM
#25
To me the rev range looks like where the lock up in the torque converter engages.
1st to do is reset the adaptation values of the tip computer.
If the transmission never got serviced till now, might be the time to consider it.
Less then smooth operation could also point to the valve body and the solenoids. Is not that much extra work to drop the oil pan of the transmission and check the valve body and the print plate and give it a thorough clean.
Flushing the transmission is an option as you also replace the atf that stays in the torque converter and you flush the other parts such as the atf cooler.
Might be it helps!
1st to do is reset the adaptation values of the tip computer.
If the transmission never got serviced till now, might be the time to consider it.
Less then smooth operation could also point to the valve body and the solenoids. Is not that much extra work to drop the oil pan of the transmission and check the valve body and the print plate and give it a thorough clean.
Flushing the transmission is an option as you also replace the atf that stays in the torque converter and you flush the other parts such as the atf cooler.
Might be it helps!
12-04-2019, 05:09 AM
#26
To me the rev range looks like where the lock up in the torque converter engages.
1st to do is reset the adaptation values of the tip computer.
If the transmission never got serviced till now, might be the time to consider it.
Less then smooth operation could also point to the valve body and the solenoids. Is not that much extra work to drop the oil pan of the transmission and check the valve body and the print plate and give it a thorough clean.
Flushing the transmission is an option as you also replace the atf that stays in the torque converter and you flush the other parts such as the atf cooler.
Might be it helps!
1st to do is reset the adaptation values of the tip computer.
If the transmission never got serviced till now, might be the time to consider it.
Less then smooth operation could also point to the valve body and the solenoids. Is not that much extra work to drop the oil pan of the transmission and check the valve body and the print plate and give it a thorough clean.
Flushing the transmission is an option as you also replace the atf that stays in the torque converter and you flush the other parts such as the atf cooler.
Might be it helps!
How can I reset the adaptation values of the tip computer?
My tip s got service before I purchased the 911.
On October 2013 Transmission electric plate + transmission oil was replaced in ~100,000~ km. Now, ~170,000km~.
12-04-2019, 10:05 AM
#27
Disconnect the negative terminal of the battery long enough would reset ECU and TCU.
Take a sample from the ATF to get an idea how it looks and smells. Further check if the ATF level is good. At 70.000km I would certainly consider to do a filter ATF refresh again. 140.000km is the workshop set interval. My advise is to do it at every 50.000-70.000km.
Take into account that with the normal procedure only half of the ATF gets replaced. You could plan to redo the refresh once or twice more after short intervals in order to get most of the old ATF left diluted.
Ideally would be to flush or to empty the torque converter manually.
If the problem lies in the transmission you will need to get the valve body checked, cleaned, if necessary refurbished or replaced. After that you might want to check the torque converter. For this the transmission will need to come off ... additional labour.
maybe there is no problem at all ... and it is the lock-up you feel engaging (maybe somewhat unsmooth).
Take a sample from the ATF to get an idea how it looks and smells. Further check if the ATF level is good. At 70.000km I would certainly consider to do a filter ATF refresh again. 140.000km is the workshop set interval. My advise is to do it at every 50.000-70.000km.
Take into account that with the normal procedure only half of the ATF gets replaced. You could plan to redo the refresh once or twice more after short intervals in order to get most of the old ATF left diluted.
Ideally would be to flush or to empty the torque converter manually.
If the problem lies in the transmission you will need to get the valve body checked, cleaned, if necessary refurbished or replaced. After that you might want to check the torque converter. For this the transmission will need to come off ... additional labour.
maybe there is no problem at all ... and it is the lock-up you feel engaging (maybe somewhat unsmooth).
12-04-2019, 10:14 AM
#28
Disconnect the negative terminal of the battery long enough would reset ECU and TCU.
Take a sample from the ATF to get an idea how it looks and smells. Further check if the ATF level is good. At 70.000km I would certainly consider to do a filter ATF refresh again. 140.000km is the workshop set interval. My advise is to do it at every 50.000-70.000km.
Take into account that with the normal procedure only half of the ATF gets replaced. You could plan to redo the refresh once or twice more after short intervals in order to get most of the old ATF left diluted.
Ideally would be to flush or to empty the torque converter manually.
If the problem lies in the transmission you will need to get the valve body checked, cleaned, if necessary refurbished or replaced. After that you might want to check the torque converter. For this the transmission will need to come off ... additional labour.
Take a sample from the ATF to get an idea how it looks and smells. Further check if the ATF level is good. At 70.000km I would certainly consider to do a filter ATF refresh again. 140.000km is the workshop set interval. My advise is to do it at every 50.000-70.000km.
Take into account that with the normal procedure only half of the ATF gets replaced. You could plan to redo the refresh once or twice more after short intervals in order to get most of the old ATF left diluted.
Ideally would be to flush or to empty the torque converter manually.
If the problem lies in the transmission you will need to get the valve body checked, cleaned, if necessary refurbished or replaced. After that you might want to check the torque converter. For this the transmission will need to come off ... additional labour.
I will definitely incorporate in my next service replacement fluid transmission and cleaning as much as possible of the things they have access to (without disassembling the transmission).
I hope this solves the problem and I hope I do not have to dismantle transmission.
If you have any other ideas, I'd love to hear. This hesitation is very frustrating. Especially in traffic jams.
12-04-2019, 10:16 AM
#29
One further question before you start spending money on servicing. Is the hesitation there also when you drive the car in ‘manual’ mode? Or is it different? Any difference under different throttle application?
In manual mode the TCU is in its most sportive mapping which als changes the engaging behaviour of the gear changes and lock-up. More direct.
If the hesitation is not there in Manual mode it might be that an irregular slipping behaviour of the lock-up in drive mode is causing the hesitation.
Controlled slipping of the lockup is used to improve driving comfort. But if the slipping starts to become irregular (due to problems in valve body or worn torque converter, lock up friction) it could cause the sudden load and unload on the engine which could be the hesitation described.
In manual mode the TCU is in its most sportive mapping which als changes the engaging behaviour of the gear changes and lock-up. More direct.
If the hesitation is not there in Manual mode it might be that an irregular slipping behaviour of the lock-up in drive mode is causing the hesitation.
Controlled slipping of the lockup is used to improve driving comfort. But if the slipping starts to become irregular (due to problems in valve body or worn torque converter, lock up friction) it could cause the sudden load and unload on the engine which could be the hesitation described.
12-04-2019, 10:24 AM
#30
One further question before you start spending money on servicing. Is the hesitation there also when you drive the car in ‘manual’ mode? Or is it different? Any difference under different throttle application?
In manual mode the TCU is in its most sportive mapping which als changes the engaging behaviour of the gear changes and lock-up. More direct.
If the hesitation is not there in Manual mode it might be that an irregular slipping behaviour of the lock-up in drive mode is causing the hesitation.
Controlled slipping of the lockup is used to improve driving comfort. But if the slipping starts to become irregular (due to problems in valve body or worn torque converter, lock up friction) it could cause the sudden load and unload on the engine which could be the hesitation described.
In manual mode the TCU is in its most sportive mapping which als changes the engaging behaviour of the gear changes and lock-up. More direct.
If the hesitation is not there in Manual mode it might be that an irregular slipping behaviour of the lock-up in drive mode is causing the hesitation.
Controlled slipping of the lockup is used to improve driving comfort. But if the slipping starts to become irregular (due to problems in valve body or worn torque converter, lock up friction) it could cause the sudden load and unload on the engine which could be the hesitation described.
There are certain (rare) situations that this does not happen at all and everything is smooth. Sometimes I feel it has to do with the power of the statement I give. But it's really hard for me to point out anything specific.
I've read a lot that happens to both manual transmission and TIP S owners.
My hesitation is only at the beginning of driving, first or second gear. No matter if the vehicle is cold or hot. The RPM falls and comes back, like engine braking, a knock on the back and then everything works smoothly.
By the way: I always only drive in M mode with Chrono Sports
In D mode the TIP S is very disappointing (unlike PDK which responds well to both D and M).