Weird 996 problem. No start

[j911brick]

I have a weird problem with a 996 that doesnt want to start. It doesnt want to start when its been warmed up for a couple hours, and then shut off for several minutes. It will restart if you try to start it immediately, but if you let it sit for a few minutes it wont restart for a couple hours after everything has cooled back down again. Not throwing any codes. Replaced: fuel pump, fuel pressure regulator, 3 crank sensors, Idle stabilizer, engine compartment temp sensor, and water temp sensor. I have verified the fuel pressure is good and the injectors are firing. I am pretty much at my wits end on this. Any ideas?

james

[De Jeeper]

Well u need fuel, air and spark to make a motor run. Sounds like u have covered fuel, i assume u have checked for rodents in the air filter housing . Next u have to check spark. I gonna guess bad coils? Hard to diagnose over the internet, u may need to find some diagnostic tools.

[j911brick]

Originally Posted by De Jeeper

Well u need fuel, air and spark to make a motor run. Sounds like u have covered fuel, i assume u have checked for rodents in the air filter housing . Next u have to check spark. I gonna guess bad coils? Hard to diagnose over the internet, u may need to find some diagnostic tools.

All six coils would have to fail at once for it not to start.

[FPB111]

Check your purge control valve. It lives on the drivers side of the throttle body.

Part no 996 110129053 m100
Looks like this

[j911brick]

Originally Posted by FPB111

Check your purge control valve. It lives on the drivers side of the throttle body.

Part no 996 110129053 m100
Looks like this

I have been suspicious of that valve, but dont know how to test it.

[FPB111]

With the electrical plug unplugged no air should be able to pass through in the direction of the throttle body. Really not either way. With power to it air should pass through.

This valve allows fuel vapor to pass through the charcoal can purging it by pulling fuel vapor through the engine.
This alters the fuel/air mix in an uncontrolled manner.

With the engine fully warmed up, running at a predetermined RPM, this valve clatters like a fuel injector as long as a vapor recovery test is not being performed.

Next time this happens try holding the gas pedal down to see if it helps.

[j911brick]

Originally Posted by FPB111

With the electrical plug unplugged no air should be able to pass through in the direction of the throttle body. Really not either way. With power to it air should pass through.

This valve allows fuel vapor to pass through the charcoal can purging it by pulling fuel vapor through the engine.
This alters the fuel/air mix in an uncontrolled manner.

With the engine fully warmed up, running at a predetermined RPM, this valve clatters like a fuel injector as long as a vapor recovery test is not being performed.

Next time this happens try holding the gas pedal down to see if it helps.

Thanks. I'll check it out if we still have a problem.

[j911brick]

Originally Posted by FPB111

Check your purge control valve. It lives on the drivers side of the throttle body.

Part no 996 110129053 m100
Looks like this

Youre the winner. This valve was the problem.

[rfaust6024]

Amazed at the expertise of the people on this site. Another problem solved.

[EPiK]

wow. that was impressive. kudos and congrats

[j911brick]

And if you want to know if this valve is a problem then just clamp off the soft portion of the hose. Car will run fine like that.

[CrossT]

Interesting thread. On a 997.1 C2S (3.8 ltr) where is this purge control valve?
I think this car has a different evap setup from a 996 or a 3.6 liter 997

Thanks
Todd
07 C2S cab

[j911brick]

Originally Posted by CrossT

Interesting thread. On a 997.1 C2S (3.8 ltr) where is this purge control valve?
I think this car has a different evap setup from a 996 or a 3.6 liter 997

Thanks
Todd
07 C2S cab

On a 996 the valve is adjacent to the throttle body in plain sight. Could very well be different on the c2s since many things are different on the S.