indraporsche

Does the Porsche 993 fuel filter at the fuel tank inside the front compartment need to be cleaned ?
Thank you.

Steve Weiner-Rennsport Systems

I like to change those every 50K.

Its cheap ($51) insurance from getting stuck with a big repair/tow bill if you pick up a load of contaminated gas.

indraporsche

Thanks Steve, my 993 is still below 20k miles, i asked this because i'm doing to figure out what could be the problem that my car won't pass 5.5k rpm.
, just like fuel starvation.
I replaced the rear fuel filter, air filter, spark plug, engine oil & oil filter already. Cleaned the ISV, Throttle body , intake system and other upper parts of the engine.
Also checked the distributor cap, rotor and belt.

Next project to do, check the fuel pressure, fuel delivery, fuel pump (this is the one i suspect to be the cause, the fuel pump is noisy lately.

Garth S

There was a very recent thread on a car that could not exceed ~5500 rpm: the root cause in that case was excessive backpressure due to a contaminated catalytic converter, IIRC.
Does your car have a cat? OBD I or OBD II? What is the quality of local fuel?

AOW162435

Steve,
Is it located by the sender unit?

Andreas

JasonAndreas

The fuel tank filter is located at the very bottom of the tank which means you have to drain the tank to get to it. So really think hard before you decide to replace it. There are few 964 owners (myself included) that have taken a look after 100,000+ miles and it turned out to be a complete waste of time! I think the lesson we learned was to replace it only when we replaced the fuel pump.





photos from Eric Kessel

AOW162435

Jason,
Excellent visual - thank you!

Andreas

indraporsche

To Garth - my car has an OBD 1 and my local fuel is RON 96 if i'm not mistaken.
But i don't think that this issue happen because of the fuel quality, i always use to fill the fuel at 2 gas stations only and it's been 5 or 6 years no issue.
The catalytic on my 993 seemed ok and clean a few months ago, but i'll check it again, who knows something goes wrong.

To Jason - i believe that your opinion is correct, but perhaps i'm just curious since i opened the cleanable rear billet fuel filter and found that the inner part of the fuel filter was dirty.
Anyway i won't do it before i check the fuel press, fuel delivery.
If i found that the fuel press or the fuel delivery is not good, it could be the fuel pump goes bad or the intank fuel filter was dirty.

Thank you Jason for the very clear photos you attached.

indraporsche

To JasonAndreas - Do you know how to access the intank filter on a 993, should i dissamble the fuel tank from the front compartment or i can access through the bottom of the car ? Thanks.

indraporsche

Thanks to all helps, found the problem already - the fuel pump is bad and need to be replaced.

Knight

Just bumping an old thread, curious if people here do treat this like a maintenance item - see a comment suggesting it's a waste of time? Rarely here about this in 993 discussions. I realize the rear fuel filter is commonly done @ 60K miles servicing.

Possibly having an issue with my Fuel Sending Unit so thinking about replacing along with this filter too.

71-3.0-911

Ive never seen this filter changed as a maintenance item. However, and I'll probably get a lot of flak for this, I do believe the fuel pump is a maintenance item and should be changed every 100k. Mine was howling at 97k miles and I had intermittent fuel pressure/no start issues/blown DMEs. It is still my firm belief that part of the major reason DME relays overheat and fail is due to increased current draw by a failing pump. Changed pump, moved to F9 relay. Never again a single issue and quiet as a mouse.... well at least the pump is quiet...

-Scott

geolab

Ask me how I know !
I learnt the phrase here on rennlist, and I really think it is very symbolic, and factual!
The tank filter in a 993 has its base seated 10 centimeters above the real base bottom of the tank.
It stays always clean. Debris if existing, are lower.

Knight

Hi Geo - so are you saying a waste of time, the filter rarely get dirty. Good to know!

MarinS4

I haven't seen that filter clog but it sure does start to distort from being submerged in fuel for 20+ years.

I can see the value in flushing out the tank and changing this filter. The only way of knowing if it's needed or not is to do the work. With all of the variables of gas sources who knows what to expect.