uschoice

My '05 with 21K on it also smokes a little at start up. Just had the plugs, coils, injectors and MAF changed, and it had no affect on reducing the smoke at first start up.

Macster

A partial fuel tank fill up can be easily explained by a premature shut off of the fuel nozzle. My Turbo has manifested this since day one. (The Boxster only rarely.)

I resorted to simply turning the fuel nozzle nearly upside down while I fuel the car. I have to hold the thing but the fueling takes little time.

Sometimes though the nozzle shuts off to my mind prematurely and because I hate partial fill ups I will walk around and insert the key then turn on the ignition and check the fuel level. Once in awhile -- maybe 1 fill up in 20 -- the level is down and the nozzle did shut off early for some reason. Some more fuel has the level up where it should be and where I like it.

If you are seeing erratic fuel level after as best you can being consistent with the fueling there maybe something wrong in the fuel tank. About all I'm aware of for sure is that some Turbo's have a siphon jet hose fail and the car runs out of fuel at half a tank.

But this partial fueling symptom -- if it is not just your technique -- coupled with the engine stalling suggests to me there may be a fuel supply problem.

However, in the event I'm right this will not mean the problem will fix itself and tearing into a fuel tank is not something I'd like to see a home auto mechanic attempt.

Sincerely,

Macster.

sbefar01

I had no idea the nozzle would stop early, since I live in NJ and are not permitted to fill our own tanks i will just tell the attendant ill take care of my own fill, they really dont care that much. Indications are that i will have to turn and hold the nozzle upside down for the last 1/4 tank (if im understanding you guys correctly) 4.25 gallons shouldn't take long. Strangely, my stalling issue has resolved the past 6 days, I will throw more Techron Fuel System cleaner in there for the sulfur deposits etc, maybe the car was just sitting for too long and gunked up before i got it on the road and moving again.

neanicu

Or if you have him do it, just sit in the car and put the key on(don't start) and look at the level. I bet you that the first time the pump shuts off your tank is not full!

SSST

It's the vapor recovery nozzles you have to use in most urban areas now. I think they create back pressure that causes the nozzle to shut off early. Turning the nozzle upside down seems to work for some reason.

I never have the problem with the old school nozzles you find on the highway in rural areas.

neanicu

That makes sense. What I don't understand is why it does it only on my TT. My E55 fills right up!

sbefar01

neanicu , your right! ha

Macster

Unless the car sits for a long time chances are the sitting around didn't affect the fuel system.

What is more likely the case is the car was just not driven enough, hard enough, treated to short trips.

Every time the engine is shut off the engine will heat soak and the injectors are located right where they'll suffer the most from this.

The heat will cause some fuel to evaporate from the injectors. This over time can lead to deposits at the injectors, deposits which can affect the amount of fuel injected but also and more importantly its spray pattern.

Also, the above type of usage can result in intake valve, combustion chamber deposit build up all of which can negatively affect combustion.

Coupled with the above if a less than high quality fuel (short on detergents) was used...

In this case, Techron might just be the ticket.

But don't over do it. My info is the stuff in the bottle is very concentrated and one doesn't need to use it very often at all.

Also, the advise I've received is when after using this stuff is to change the engine oil/filter. The additive has fluid and vapor deposition phases and the result is some increase in oil contamination. This dilutes the oil (thins it, which ain't good) increases the amount of other contaminants which will combine with water in the oil to form acids.

Acids in oil ain't good at all.

The only real way to address the above is to after the last bottle of Techron is used up, when the gas to which Techron was added is down to say 1/4 tank left, is to do an oil/filter service.

Sincerely,

Macster.

SSST

I think it has to do with the size of the tank and venting of the tank. It just seems to be a quirk of these cars.


I'm just guessing, but it's the only thing that makes sense.

sbefar01

Thanks, I am driving the car everyday now. The startup issues are resolving, no problems anymore after 2 weeks of consistent driving. The car wasn't being driven much by the previous owner. I just put in my 2nd bottle of Techron and i think that should take care of the deposits. Ill then do an oil change in a few hundred miles so there is no contamination from the Techron, good call, Thanks! This car is thanking me now bc it wants to be driven