Thanks for the advice.The filler tube was replaced when it split during an alternator swap.

I have several new codes on the Durametric

To test a theory I disconnected the mass air sensor while the car was running so I attribute these three codes to that; P1125, P1123, and P102. Am I sound in my thinking or way off base?

P0446 is still present ( I rechecked all lines but don't have access to a compressor to blow the lines) along with a new code, P0444 -Solenoid valve 2 for carbon canister open circuit. Does this mean the valve has failed? If so is is valve #6 or #1 on the diagram (link to Renntech http://www.renntech.org/forums/topic...code-is-p0455/)

The cannister looks okay although for the life of me I couldn't figure out how to remove it, so I disconnected all the hoses and reconnected them.

 

Are the symptoms still the same that the car cranks but can't start randomly?

If you suspect the evap system is affecting it, you can disconnect the purge valve from the throttle body and use a rubber cork of the right size to plug the hole in the throttle body and then re-crank the car to see if it starts.

 

Thanks for the great suggestion....I will plug the hose today and take drive to test.

I've read what I believe to be every single tech article, DIY and forum thread even remotely related to my problem (CPS, EVAP system, fuel system) and I've decided chase the EVAP path as it seems the likely culprit.

With the fuel pump, fuel filter, gas cap, and operating purge valve being replaced, and cleaning the mass air sensor, throttle body, and IAC valve I'm confident I will find something soon.

 

Just one clarification. You need to plug the hole on the throttle body (and maybe the hose itself too as it will emit fuel vapor so it may not be safe to drive the car around with the open hose). I meant to say do the check only when the no-start occurs but turn off the engine and connect everything back if you need to drive the car.

Also, the crank sensor is still a suspect although usually it fails when hot but your problem does not seem to be temperature dependent.

 

It is still very random, but occurs more frequently when hot. I still suspect the CPS as well, so I will replace it. I was able to locate it when I changed the fuel filter, so it shouldn't be too much trouble.

as for disconnecting the valve, it's normal state is closed so I simply disconnected the plug and will see if that has an effect.

Thanks for all of your feedback. It's nice to have someone to bounce ideas against.

 

Additional question(s)

P0444 Solenoid valve 2 for carbon canister Open circuit...Can someone point out which valve this is?

P0446 Shutoff valve activated charcoal filter (function) below limit value. Same question, which valve is this.?

 

Check out this diagram of the carbon canister http://www.autoatlanta.com/porsche-p...section=201-20

I think all that stuff is located behind the passenger side wheel liner.

Picture http://www.renntech.org/forums/topic...anister-valve/

 

That may not give you conclusive result because the valve may have failed and is stuck open. The whole point of disconnecting that hose is to separate the throttle body from the evap system. If the valve is stuck open, the throttle body will suck in all the gas vapor and create a high vacuum in the gas tank that prevents the fuel from being pumped to the engine.

Another indirect way to test it is when the engine doesn't start, just loosen up the gas cap and that will release any vacuum.

 

The valve is stuck close. I can see the internal valve and it is in the close position and when air is applied to the inlet of the valve non passes through.

 

What if you apply power to the valve?

 

I see this is an old thread but just wanted to see if my situation of no start has any suggestions. My 1999 996 tiptronic had a new fuel pump and sender unit a little more then a year ago when I had a no start issue after that ran fine for a year. Sounds like same problem again but wanted to see if any other possible issue comes to mind from anyone. Relay and fuses are good if I spray starter fluid into intake car fires right up, thoughts?
thanks
Rich

 

Need to check the fuel pressure on the fuel injector rails. Check or replace the fuel pump relay. I see you checked the relay and fuses, but something is not right. Only a pressure check will tell you for sure. Could be the fuel pump or connections. Faulty fuel pressure regulator?

 

Pick up tube on the fuel pump is know to come off or fail. Pull the pump to verify its still together. Also the pump may have just failed again?

 

Besides checking the fuel pressure. You can just check it with a small screwdriver at the driver side fuel rail shreder valve and can check the injectors (the one on the drivers side is the easiest to get to) if they get power with a noid light. Is the tach needle bouncing when you are cranking the engine over with the starter? I had a failed crank position sensor that cut the signal to the injectors but it would start up with starter fluid.

 

I recommend checking the fuel rail pressure first, was showing stepson how to replace his failed fuel pump, all worked good for two months, towed back home and found rail press. is zero, had him pull the fuel pump and found pick up tube not connected. ouch