I have an '03 996TT with an EPL tune. The car has developed a warm start problem. It starts just fine when cold, but if it's still warm, it cranks for 15 seconds before puttering to life.

I was told by my tuner that it was the little silver metal check valve on the octopus of lines coming off the fuel pump. Given that I have replaced two fuel pumps because the u-shaped rubber hose split, I had a spare check valve. I installed it thinking it would solve the problem, but no luck. There is another white plastic check valve in the same area, but I am reluctant to keep changing out parts guessing at the problem.

Anyone here solve a similar problem? I do think it's a fuel related issue, but I don't know how to solve it.

BTW, once started, hot or cold, it runs fine.

Thanks

 

Sounds like vapor lock on older cars. Are coils good as they can act up when hot.

 

Coils are good. Replaced last year with new plugs as well.

 

Fuel or spark have you checked fuel pressure has fuel filter been changed lately.

 

i recommend you to do a fuel pressure test and monitor pressure when engine is hot ignition off ...
GL

 

Really sounds like vapor lock. Have you tried to cycle the key to run the fuel pump say 5 or 6 times then try to start the car?

 

^what I said on R'list, seems like typical vapour lock scenario

 

Joe,

I was just thinking about your issue and remembered you posting about having an inline pump. The inline pump may be locking and the psi from the first pump may be freeing the second pump? I have had bad luck with 044 pumps.

 

Thanks all.

I have been away from the car, but will be back to it this weekend. I appreciate all of the helpful hints. I will try to post a resolution here once resolved.

BTW, I don't have an inline pump. Just a standard single OEM pump in the tank.

 

I have the same problem intermittently and I've been living with it for a year now. When the car is just the right temp, not cold and not a hot restart but after sitting for a couple of hours and still warm if I start it it will fire up and sputter and I have to floor the gas pedal. I see black smoke when this is happening and after 10 seconds or so of reving under 500 and wanting to die it will rev normally and continue to run fine. I always thought because of the black smoke that it was just getting too much fuel for the startup condition it was in.
I have the same injectors as you I think.
It is a pretty embarrassing problem and I'm glad it rarely happens. I was working with Dave at EPL and he left. Since the issue isn't really major I ignore it but I will be watching this thread to see what your resolution is.

 

I bought a fuel pressure gauge, and am now on the hunt for the right adapter to fit the large schrader valve no the fuel filter. I have seen threads on part number, so I am just trying to find someone who can order it.

In the meantime, the car is in the shop for a tech inspection, so I asked them to throw a fuel pressure gauge on it to see what fuel pressure is doing on warm starts. I'll report back when I learn more.

 

With Spring around the corner, I am back to prepping the 996TT for another track season.

I still haven't solved my warm start problem. Took the car to my local mechanic, who is pretty good, and he was able to replicate the problem, but not fix it. He did put a fuel pressure gauge on it when hot and not starting easily and he said it had plenty of fuel pressure (I think 60 lbs). He thought it was getting too much gas because it smelled very rich when if finally started.

Interestingly, if I crack the throttle a little on while cranking, it appears to start easier.

Also, turning the key on and waiting 15 seconds doesn't help anything.

I am no expert, but did have one mechanic who is no longer around (Dave at EPL) say that he thought it might be a bad check valve near the fuel pump. The aluminum one. Anyone here with more knowledge than me think this is a plausible culprit?

If I pull the fuel pump and check both check valves(aluminum one and white plastic one), should I be able to blow air through them in one direction and not the other (as in clean it up and then try to blow air through it with my mouth)?

I really want to get beyond this problem, but don't want to change a fuel pump or check valve if I am wasting my time.

thoughts?

 

I remember in my Audi a problem like this would usually be a failing coolant temp sensor.

 

Long shot - calibrate the throttle?

 

Sorry to hear you have that problem.
And I have a cold start up problem in cold weather for the first several minutes only..I made a post for some info help yesterday..