993 Acceleration Performance Variable
06-11-2001, 05:05 AM
#1
2nd Gear
Thread Starter
Join Date: Jun 2001
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
993 Acceleration Performance Variable
Hi
I've owned 2 993 Porsches in my life. The First a 993 C2 (1994) and my current car, a 993 C4S (1997). Both seem to display an annoying quirk:
Sometimes, the acceleration just doesn't seem to be there and the car appears a little sluggish. At other times, it's normal and what you'd expect from a Porsche. Any Clues ?
The acceleration characteristics can change during a trip or on a day by day basis and are independant of the gear you happen to be in.
Also, the acceleration sound of the car seems higher pitched during the times that it is not behaving itself properly.
It doesn't appear to matter whether it's hot, cold, rainy or dry outside.
I know it's not the Clutch, because when I first noticed this i assumed the clutch was worn, but replacing it really made no improvement.
What else could i look for ?
Both cars were obviously regularly serviced at Porsche.
Thanks, Mike.
I've owned 2 993 Porsches in my life. The First a 993 C2 (1994) and my current car, a 993 C4S (1997). Both seem to display an annoying quirk:
Sometimes, the acceleration just doesn't seem to be there and the car appears a little sluggish. At other times, it's normal and what you'd expect from a Porsche. Any Clues ?
The acceleration characteristics can change during a trip or on a day by day basis and are independant of the gear you happen to be in.
Also, the acceleration sound of the car seems higher pitched during the times that it is not behaving itself properly.
It doesn't appear to matter whether it's hot, cold, rainy or dry outside.
I know it's not the Clutch, because when I first noticed this i assumed the clutch was worn, but replacing it really made no improvement.
What else could i look for ?
Both cars were obviously regularly serviced at Porsche.
Thanks, Mike.
06-11-2001, 03:04 PM
#2
RL Technical Advisor
Hi Mike:
I would sure like to have more data since solving these things from afar isn't easy.
My first guess is that your car is not happy about the fuel that you are using and are experiencing some knock sensor activity that would definitely account for the performance variations that are experiencing. Plugging in a scan tool like the Hammer or even a generic OBDII one, would show this in real time.
Changing brands of premium fuel for a few tanks will also help, perhaps. You must be using 92 octane fuel, as minimum in these cars. If you have Sunoco 94 in your area, I would try that too.
How old are your oxy sensors?
There is no question that a scan tool would provide some needed data to resolve this.
--
Steve Weiner
Rennsport Systems
I would sure like to have more data since solving these things from afar isn't easy.
My first guess is that your car is not happy about the fuel that you are using and are experiencing some knock sensor activity that would definitely account for the performance variations that are experiencing. Plugging in a scan tool like the Hammer or even a generic OBDII one, would show this in real time.
Changing brands of premium fuel for a few tanks will also help, perhaps. You must be using 92 octane fuel, as minimum in these cars. If you have Sunoco 94 in your area, I would try that too.
How old are your oxy sensors?
There is no question that a scan tool would provide some needed data to resolve this.
--
Steve Weiner
Rennsport Systems
06-12-2001, 05:05 AM
#3
2nd Gear
Thread Starter
Join Date: Jun 2001
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Steve - Many thanks for your reply.
I'll chekc at the gas station - I think that they have 94 and 98 octane fuels. When I bought my first Porsche the sales man told me that it wasn't really necessary to use the 98 Octane stuff, except maybe for high altitude, cold day driving - so I didn't bother.
Maybe that's the difference. To be honest I always wondered wether it was just a fuel company marketing campaign to make you want to buy more expensive fuel...
..by the way - It's a clear sunny day and 15 deg C this morning and the car was going great!
I'll try the 98 octane fuel and see if that makes a difference.
Thanks again, Mike.
I'll chekc at the gas station - I think that they have 94 and 98 octane fuels. When I bought my first Porsche the sales man told me that it wasn't really necessary to use the 98 Octane stuff, except maybe for high altitude, cold day driving - so I didn't bother.
Maybe that's the difference. To be honest I always wondered wether it was just a fuel company marketing campaign to make you want to buy more expensive fuel...
..by the way - It's a clear sunny day and 15 deg C this morning and the car was going great!
I'll try the 98 octane fuel and see if that makes a difference.
Thanks again, Mike.
