AJN334

CTT has approx. 80k on it.

I just recently replaced the PCV Ventilation Tube a few weeks ago after the car not starting after filling with gas. When that happened I was also getting the PCV/tighten gas filler cap code. After replacing the part and clearing the code the car ran beautifully......for 3 weeks.

NOW. I went to get in the car, started it and it cranks over and fires fine. However I notice it is idling higher then normal. After about 10 seconds revs completely drop to zero and it dies.

After trying restart a few times same issue only now it dies quicker. Fires fine idles for a few seconds and dies.

No CEL is the other issue I am facing. I figured if I tried to restart it a few times it would throw a code but that's not the case.


I have read a few very vague posts about bad gas, bad fuel filters and fuel pumps?

What is the most likely scenario? How much does the dealer charge to replace the fuel pump?

Any information would very helpful, thanks!

Hartdude

I'm assuming you have a 4.5 turbo here...

I would check the fuel pumps. We can use the drive links on the PIWIS to activate the fuel pumps, to see if both are operating. If you don't want to take it to the dealer, you can open the access holes for the fuel pumps under the rear seats, and check it yourself. You can jump the fuel pump relays individually to check them. The relays are located under the hood in the cowl area, next to your brake fluid reservoir. I usually also hook up a fuel pressure gauge to verify proper pressure at the fuel rail, and check volume delivered. You're looking for about 800ml over 15 seconds for the left pump, and 800ml over 10 seconds with both pumps activated. With the car off, and the pumps activated, you're looking for about 43 psi.

You're probably looking at 1.5 to 2.0 hours labor to replace a fuel pump.

AJN334

Hartdude -
Correct, 955 Turbo. This is great information. Do you know of a DIY writeup for this? I have never performed fuel related maintenance. What tools are needed?

Are the fuel pumps inside the tank as this site references?
http://www.ecstuning.com/Porsche-200...uel/ES2020903/

bigbuzuki

Excellent article below. Could be the check valve that lives in the filter or filter itself restricting flow.

https://rennlist.com/forums/porsche-...o-do-next.html

AJN334

Also - I tried unplugging both MAFs to see if that would at least get the car running if one of those were the issue.

Not luck though car still dies, even with trying to give it revs...

mudman2

Is your gas tank full ?

When one side fuel pump goes bad, the other can keep the car running but only if the level is high. You don't give the year of your car but if it is pre 2008 then I would also guess a fuel pump

AJN334

Good info, car has below 1/2 tank of fuel. I will fill it and see if that makes a difference. If I still have issues that should tell me it may not be one of the fuel pumps. Probably pretty rare for both to go out at once.

Also, yes...Car is a 955 - MY04.

AJN334

Update, after filling the car with fuel it still dies after a few seconds of idling. Could both pumps go out at the same time or does this mean the issue is not the fuel pump. Also still no CEL...

mudman2

its unlikely that both would go at the same time, have you checked all fuses ?

The fastest way is to hook up a Durametric to read any error codes then post them here.

How old is the battery ? this can cause all sorts of weird issues although this one does not sound as if it is unless there are other things going on you have not mentioned

bigbuzuki

How much fuel pressure is at your fuel rail manifold?

AJN334

No blown fuses and I hooked up my trickle charger to the batteries to get a reading, both are very healthy. I did not check the fuel pressure as I could not find any DIYs.

Sadly I had the car towed to my local Porsche dealer since its only a few miles away. I figured if it is a fuel pump or the throttle body needs re-adjustment via durametric those are beyond my capabilities.

I will update everyone once I get word from the dealer. Thanks to all for the contributions...

AJN334

I have been told both fuel pumps have completely failed. This was concluded via testing each fuel pump. Seems odd both go at once. Also my CTT only has 80k on it. Seems like pretty aggressive wear even for a high performance car??

Are the early units known for failure? Were the fuel pumps known for this and revised at some point?

mudman2

My 04 had only 1 go during its life with me but I have heard tell of people where multiple did go, its age rather than miles by the sounds of it

beaconsfield

Does anyone have an idea as to what it should cost to have both fuel pumps replaced by an indy? I'm having similar issues, and suspect my fuel pumps are failing. I'm at 86k miles with a 2005 CTT.

mudman2

I know the dealer charges around $800 a side I am sure you could get them much cheaper if you get the parts from sunsetimports