CEL light, please help.

[jshin80]

hi.
i just purchased 01 boxster s.
after going through the emission test, the cel keeps coming on.
i went to a shop and scan the code, but nothing... cel light keep comes on and off.
my injectors, fueling, everything is good, but the cel keep comes on.
cel comes on when i do 6000RPM+ on a high way.
is it post O2 sensor? MAF? Injectors?
does anyone had same problem???
please help,

[Marc Gelefsky]

Is your gas cap on tight?

[jshin80]

yes, i am sure the gas cap is closed all the way. i have a habit closing more than enough always.
thanks for the help.
any others???

[Marc Gelefsky]

Originally Posted by jshin80

yes, i am sure the gas cap is closed all the way. i have a habit closing more than enough always.
thanks for the help.
any others???

I know here in NJ they check the gas cap during emissions inspection so I thought perhaps the inspector did not make sure it was tight.

[denverpete]

Originally Posted by Marc Gelefsky

I know here in NJ they check the gas cap during emissions inspection so I thought perhaps the inspector did not make sure it was tight.

I believe there is also a recall or TSB outstanding for the gas cap on some vehicles.

I also find it a bit odd that the CEL goes off but no code is recorded...

[jshin80]

Originally Posted by denverpete

I believe there is also a recall or TSB outstanding for the gas cap on some vehicles.

I also find it a bit odd that the CEL goes off but no code is recorded...

yes, it is strange...
cause whenever i go to scan my car, the cel's off.
i've tried to scan my car when the cel is "ON" but i couldn't make it to go off.
that's why i am not getting any answers from shop...
so, shall i get new gas cap???
it doesn't cost much, so i am just going to try it.
thanks for your help~~~

and plus, when they did emission, they had to modify the exhaust system to pass the emission.

[PorscheDoc]

You need to take the car to a porsche dealer and have them scan it with their PST2 or PST3. It can read the pending codes that caused the CEL, even when it is not currently on (a normal reader can not do this)

[denverpete]

Originally Posted by jshin80

....and plus, when they did emission, they had to modify the exhaust system to pass the emission.

Okay, now that's just scary.

Why would you have to modify the exhaust to pass emissions? Exactly what was modified and how?

I'm thinking you aren't giving us the full story here. What other modifications have been done to this car? Do you have a cold air intake or K&N? Aftermarket exhaust or exhaust by-pass?

[jshin80]

okay here goes the full story.
my car is imported from Japan(euro version boxster s).
when it gets imported to my country(s. korea), they have to go through the very stricted emission test. more like sound decible test. i don't know what they did, some say, they stick a socks or weld more than 1 muffler to pass that emission test. this CEL happens right after the emission test.
and here, we don't have a reputable porsche dealer. (we have one porsche dealer, not many porsches either) so i am trying to get help from here.
i tried to put really high octane(premium +) gas at first. well this didn't help.
went to a shop who has scanner, but no code was found altho the CEL comes on and off. i lose very little power when the CEL comes on. not that noticeble.
even doing more than 120mph, the car seems okay and pulls hard(maybe very very little drop on power)
in normal driving, CEL doesn't come on, but when i push it hard in highway, the CEL comes on right at 6000-6300rpm.
stop the engine and restart the engine, the CEL light goes off.
my thought:
post O2 sensor is going bad --> but it has to show on scanner.
fuel injectors are bad --> has to show on scanner and i would lose significant power.
MAF sensor is bad --> i don't lose power or going into limp mode.
???
if i ever want to visit authorized porsche dealer, i have to pay $2000 to register and it doesn't pay anything. i still have to pay for using scanner($70 at least).
this little thing is making me go crazy here...
please help~~~
oh yeah, my car is completely stock right now.

oh today, i scanned again,
cylinder 3.5.6 misfiring.
but this code goes away after day or two with normal driving.
man...

Originally Posted by denverpete

Okay, now that's just scary.

Why would you have to modify the exhaust to pass emissions? Exactly what was modified and how?

I'm thinking you aren't giving us the full story here. What other modifications have been done to this car? Do you have a cold air intake or K&N? Aftermarket exhaust or exhaust by-pass?