Our 996 refuses to run over 4500RPM!!!
Thread Starter
Intermediate
Joined: Feb 2020
Posts: 46
Likes: 8
From: France
Our 996 refuses to run over 4500RPM!!!
Strange thing: our 996 refuses to accelerate over 4500-5000RPM!
It is running well under this limit; good acceleration... But it begins toi jerk horribly when it reaches 4500RPM and refuses to pass over!
It's equiped with a tiptronic gearbox. Changing gear is not a problem and works perfectly, in manual or automatic mode.
Any idea??
Thanks!
It is running well under this limit; good acceleration... But it begins toi jerk horribly when it reaches 4500RPM and refuses to pass over!
It's equiped with a tiptronic gearbox. Changing gear is not a problem and works perfectly, in manual or automatic mode.
Any idea??
Thanks!
Nordschleife Master
Joined: Jan 2018
Posts: 7,371
Likes: 4,821
From: Delaware
Probably not the issue but check to make sure there is good flow out of the exhaust. U should be able to detact it with just a glove on over the exhaust pipe to see if u had a cat come apart and restrict flow.
Race Car
Joined: Aug 2017
Posts: 4,938
Likes: 2,540
From: Central MA
Split fuel line in the fuel tank. It will keep getting worse.
Take out the fuel pump and inspect all the hoses. The "U" shaped rubber hose is probably split. Replace it with submersible fuel hose (not ordinary fuel hose!).
Take out the fuel pump and inspect all the hoses. The "U" shaped rubber hose is probably split. Replace it with submersible fuel hose (not ordinary fuel hose!).
Thread Starter
Intermediate
Joined: Feb 2020
Posts: 46
Likes: 8
From: France
I can't imagine an issue with fuel line.
Why? because I did tests at full charge under 4500RPM and accelerations are proper up to 4500RPM.
If I'm trying to pass over 4500RPM slowly; that remains the same: engine is immediately jerking horribly, Rev counter is sweeping from 2000 to 4500!!!
I'm mostly looking in direction of an electrical/electronical issue! Maybe a DME failure, or something similar.
Understand me, if you stay under 4500, the car is going very well, even if you accelrate strongly or lightly.
I'll also explore another way, by servicing the tiptronic...
Will let you know...
Cheers,
Why? because I did tests at full charge under 4500RPM and accelerations are proper up to 4500RPM.
If I'm trying to pass over 4500RPM slowly; that remains the same: engine is immediately jerking horribly, Rev counter is sweeping from 2000 to 4500!!!
I'm mostly looking in direction of an electrical/electronical issue! Maybe a DME failure, or something similar.
Understand me, if you stay under 4500, the car is going very well, even if you accelrate strongly or lightly.
I'll also explore another way, by servicing the tiptronic...
Will let you know...
Cheers,
Nordschleife Master
Joined: Jan 2018
Posts: 7,371
Likes: 4,821
From: Delaware
Dont discount the fuel line. Its an easy check.....
Its a matter of volume and pressure. A split in tank line will cause the issues u r having.
Will the engjne rev over 4500 when in park or neutral (no load)?
Its a matter of volume and pressure. A split in tank line will cause the issues u r having.
Will the engjne rev over 4500 when in park or neutral (no load)?
Trending Topics
Rennlist Member
Joined: Oct 2010
Posts: 7,675
Likes: 6,939
From: Alabama USA
Keep in mind along with these other possibilities that the DME may have somehow got back into "transport mode" ..
In Transport mode the RPM's are limited along with other non-essential functions that are not necessary when transporting across the Ocean for months..
Performing a "Handover" with a PIWIS Tester will take the system out of Transport Mode.....I have seen a few cars that had gotten back into Transport Mode somehow due to some strange voltage/electrical issues..
It's worth a mention !!!
In Transport mode the RPM's are limited along with other non-essential functions that are not necessary when transporting across the Ocean for months..
Performing a "Handover" with a PIWIS Tester will take the system out of Transport Mode.....I have seen a few cars that had gotten back into Transport Mode somehow due to some strange voltage/electrical issues..
It's worth a mention !!!
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
10 Porsche Colors That Have More Personality Than Most People
Verdad Gallardo
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod
Verdad Gallardo
10 Reasons I Hate Going to the Porsche Dealership (& the 1 Reason I Stay)
Joe Kucinski
Porsche Shakes Up The Nürburgring Lap Record Table Once Again
Verdad Gallardo
6 Ways the Porsche 911 GT3 S/C Redefines Performance
Joe Kucinski
10 Wildest Homologation Specials Porsche Ever Sold
Verdad Gallardo
Super Rare RUF BTR III Comes Out of Hibernation, Looking For a New Home
Verdad Gallardo
10 Porsche Opinions That Can Start a Fight
Joe Kucinski
Rennlist Member
Joined: Oct 2010
Posts: 7,675
Likes: 6,939
From: Alabama USA
Just get to the 996 main menu , then look across the bottom for "additional menu", then select " Handover" and follow the prompts .......
If this doesn't fix it then put a fuel pressure gauge on the fuel rail and test the pressure at full throttle up to where it cuts off...Fuel delivery is the number 1 cause of full power issues...
Last edited by Porschetech3; Apr 22, 2025 at 05:22 AM.
Thread Starter
Intermediate
Joined: Feb 2020
Posts: 46
Likes: 8
From: France
Thanks for the process. I did it and wait for the result from the owner...
In the meantime, I servised the tiptronic and noticed problem with tiptro switch connector!!
Piwis indicated wrong tiptro position !!!
I sprayed some contact cleaner and all come back to normal on this point. Better than nothing!!
In the meantime, I servised the tiptronic and noticed problem with tiptro switch connector!!
Piwis indicated wrong tiptro position !!!
I sprayed some contact cleaner and all come back to normal on this point. Better than nothing!!
Thread Starter
Intermediate
Joined: Feb 2020
Posts: 46
Likes: 8
From: France
With air restriction I couldn't accelerate "foot in" at low rev!
Here the car is running perfectly with "heavy acceleration" up to 4500RPM!
Then, I'm doubful about any air restriction due to dirt air filter.
But, thanks for your suggestion.
Here the car is running perfectly with "heavy acceleration" up to 4500RPM!
Then, I'm doubful about any air restriction due to dirt air filter.
But, thanks for your suggestion.
Rennlist Member
Joined: Mar 2021
Posts: 1,765
Likes: 571
From: Hockley TX
Boy then it has to be on the fueling side. Does it struggle after 4500 or just dies off? If it's struggling, it's fuel pump or fuel filter related. It wouldn't be dirty injectors if it's pulling hard to 4500....so my thought is it would have to be the fuel pump or filter? Hummmmmmmmmm