So my car has been running progressively worse since Friday.... died at a stop sign 10 blocks from my place after a 35 mile commute home of issue-free driving (and a little fun with a Carrera 4S on the bridge). So, the car died all of a sudden - figured boost leak... went home and looked it over and nothing loose or disconnected where it was obvious last time I had a leak.

Then Saturday I went for some errands and it ran okay for a mile or so and then started to hesitate some more and idle-hunt so I scrapped my last errand and headed home. Died again close to the house but got it into my parking garage space okay. Check leaks again and tightened all clamps. P1250 CEL comes up. Boost deviation something...

So today my mechanic comes out to look it over with me and sees no boost leaks and we reset the MAF and tried to drive it again - even worse bucking and instant dying. Barely got it half way down the street and back into my garage. It surely feels and acts like a fuel related problem vs MAF or boost leak.

So, I did read a ton of threads on the issue and will pressure check the pump tmrw when he comes back and also check the fuel lines. I am thinking it is one of these 2 things based on past threads.

So, if it is a fuel pump, wondering what you recommend I install. The stock replacement pump (I think it is an 040 in-tank) or an 044 (meant for in-line) or ? Most of the fuel pump threads I read were 2-3 years old so maybe the conventional wisdom has changed. Hell, everyone had you believing you needed better rods at 650 crank hp a couple years ago.

I am likely around 650-675 crank hp right now with mods in my sig.

Sorry for the length!

 

I had the same symptoms a few weeks ago. I got no CELs, my mechanic looked at the coils and they were all cracked, we replaced all 6 of them with the plugs and now the car runs perfectly...

 

Dave,

You might want to check inside the fuel tank and see if the black rubber hose in a "U shape" is split, you should be able to see it or get your hand in there to feel the hose. These have been known to go and cause this type of problem.

Ben

 

I'm with Ben. Mine did that.... twice.
Now there is an updated fuel pump part that is all hard tubing.

 

All good advice and we will check them all out! Thanks guys.

Bravo, do you have the updated hard fuel lines handy? I read your thread in my research last night and you seemed to install a newer part # pump in yours if I recall. ?

 

This is from another post of mine when I was researching the failed pumps...

Porsche knows. They've at least updated the parts when the EPA heard there was a fuel leak problem. Their response to the govt is that the leak is internal to the tank, and the bad parts have been removed from stock. The new p/n ends with -02.
Porsche pays nothing for those out of warranty.

Well I found a memo from Porsche to EPA because it is a fuel system problem stating that a bit over 8% of the newer 996TT's had pump failures but no release to atmosphere of fuel. The corrective action is a revised part and old parts pulled from shelf.
Huh. I wonder as this is a report on the "newer" 996TT's. I wonder what the failure rate of the old ones are given the longer exposure to ethynol.
Also, 8% were covered by warranty. I wonder if another 20-30% or more were out-of-pocket? Mine is going on it's second replacement pump on a 20k mile car and I'm a little hot about buying a $500+ pump that's known to be a problem. Hopefully the newest incarnation does the trick. Just wish Porsche would pick up the part, I'll eat the tow.

Here's a link to the memo.

http://www.regulations.gov/fdmspubli...ontentType=pdf

 

Wow. So this is another thing that Porsche has found out about and not handled very well. Interesting.

Thanks much for the info and we will be sure to check those lines in the tank as well the pump itself.

 

I have a similar situation except mine dies for a split second and restarts no problem? This only happens when cruising not under load? Happens at any cruising speed? Could this be the beginning stage?

 

sounds to me like a MAF... disconnect it and see if same issue bucking persists... They do go bad when your pushing the limit on the HP.... and it seems like you are....

Is your Aquamist all good?

 

Maf was faulty and replaced, Aquamist is great

 

There comes a point when a better maf is needed... I figure your tuner can answer that best.... but I doubt it is fuel related....

 

Will check thanks

 

There are plenty of cars with more hp than mine running the stock MAF just fine. I don't think it's the MAF, but we will be swapping one in to check just in case.

After reading others' similar experiences, it sure seems to match the fuel pump/line issues.

I don't know why the Aquamist would be causing the problem.... it even activate at the rpm/boost levels I am having problems at.

So based on everything so far we are going to consider/check in this order I think:

fuel pump
fuel lines
MAF
fuel filter?
coils?

 

My problem started before I had my hp kit installed? When I had an Upsolute chip is when the problem started? Wasn't very impressed with Upsolute.

 

You have EPL tune and Aquamist kit installed now?