Patrick E

At the track this weekend, on two separate occasions, my car started hesitating as I was accelerating, almost as though I was hitting the rev limiter or had some bad gasoline. Problem started around 3000-3500 RPMs both times (about the same place the variocam normally kicks in) and the car wouldn’t get to 5000 RPMs. Each time, I brought the car into the paddock immediately and drove it around a little bit and didn’t notice the problem. The car was fine the next track session each time.

I don’t think it was gasoline since the problem occurred on two separate tanks of fuel purchased from two different locations (there were two days in between occurrences). The first time, the car had almost a full tank of gasoline; the second time, the car had about ¼ of a tank. Oil levels were fine and I didn’t have any warning lights or CELs. Also, every other session (and on the drive home) the car acted completely normal. Any thoughts?

JM993

Sounds like a fuel pump issue.

MJBird993

I had a similiar problem on track sometimes when my fuel would get low. But since this happened to you with a full tank, I guess that's probably not it. Darn. Always look for the simple answers first. Fuel filter, perhaps? PSM fault?

My other thought that is if it's running fine, then don't worry about it. But if you're at all like me, you'll obsess over it until it happens again. Good luck!

Michael

pat056

Were you at Roebling? Stock fuel system? Where on the track was it happening? How much gas did you have in the tank? How long since you replaced your fuel filters? Condition of your fuel pump?

I have a 964 race car and have been learning a lot about fuel flow(ask me why...).

Anyway, Roebling has a lot of sweepers and will magnify any weakness if fuel delivery as you end up WOT for long periods of time. Additionally, with those long sweepers comes a lot of fuel movement from 1 side of the tank to the other.

Patrick E

Just a little more info - problem occurred at VIR. Both times it happened on the back straight after Oak Tree, although the second time the problem may actually have started just before Oak Tree. Stock fuel system. The car is an '02 with 21+K miles and recently had the full Porsche 15K service (a little late!). Not sure if that service included a fuel filter or not.

pat056

Hmmm... That shouldn't happen at VIR, at least not at Oak Tree/Back straight
I would have that checked out. My 1st thoughts are:
bad gas
fuel filter
electronic gremlins
Don't know how long you've had your car or who services it for you. I have an Indy in Charlotte I use that does both race prep and regular service. I'd be glad to supply you that information.

Carrera Mike

Was your engine fully warmed up when it happened? I experienced that onced when I tried to accelerate hard on not so warmed up(approx 100F/not yet above 180F)engine in a cold day.

Ooops, I just read your post again and you did say that it happened after Oak Tree/VIR, so I take it that your engine is fully warmed up. I thought you were just coming out of the staging paddock.

Anyone knows where the fule filter is for the 996? I've replaced 993s but not this car.

gota911

MIke - here is a PET diagram of the fuel filter.

smankow

Tim, if you read the remarks, the fuel filter pertains to 2001 and prior. I don't think that it's a changeable item after that. I've looked at the various services for my '03 and fuel filter is not one of the parts replaced/serviced/etc at any time.


Steve

ArneeA

Yep. From reading RennTech, the newer fuel filters are integrated to the fuel pump. I believe 02+.

gota911

Steve, you are correct. That is why I included the "remarks" column in the first place. I actually had cut & paste two pics into one to make the type large enough to be easily read on the screen.

I guess I should have pointed that out in the original posting.

Carrera Mike

Thanks for the info Tim. Yeah I looked all over the place on mine long ago, and have given up. I hope the in-tank filter is not starting to clog up.