purge line fitting leak?

('04 Cavalier, 110K miles) Is getting a P0455 DTC. Replaced the gas
filler cap; nada. On inspection, there's liquid in the rear fitting of
the purge solenoid. (The one in the engine compartment.) I don't see
anything else wrong there (like a crack), so maybe the o-ring is
leaking?

The o-ring is deeply recessed, so changing it would be challenging, even
assuming I could find a replacement. Is there some magic sealant or
such that I could put in/on the coupling to improve the seal?

Thanks

George wrote:
> ('04 Cavalier, 110K miles) Is getting a P0455 DTC. Replaced the gas
> filler cap; nada. On inspection, there's liquid in the rear fitting of
> the purge solenoid. (The one in the engine compartment.) I don't see
> anything else wrong there (like a crack), so maybe the o-ring is
> leaking?
>
> The o-ring is deeply recessed, so changing it would be challenging, even
> assuming I could find a replacement. Is there some magic sealant or
> such that I could put in/on the coupling to improve the seal?
>
> Thanks
>
from SI

P0455

SYSTEM DESCRIPTION
The control module tests the evaporative emission (EVAP) system for a
large leak. The control module monitors the fuel tank pressure (FTP)
sensor signal to determine the EVAP system vacuum level. When the
conditions for running are met, the control module commands the EVAP
canister purge solenoid valve OPEN and the EVAP canister vent solenoid
valve CLOSED. This allows engine vacuum to enter the EVAP system. At a
calibrated time, or vacuum level, the control module commands the EVAP
canister purge solenoid valve closed, sealing the system, and monitors
the FTP sensor input in order to determine the EVAP system vacuum level.
If the system is unable to achieve the calibrated vacuum level, or the
vacuum level decreases too rapidly, this DTC sets.


from experience, I can tell you that besides a legitimate leak....
A bad purge solenoid, a bad vent solenoid, and a bad FTP sensor can ALL
set a evap leak code.

You could take everything apart and test it all manually, or you can go
to a shop with a good scan tool and a smoke machine.

If there is liquid gasoline in the purge solenoid then the canister is
ruined, btw.

GW

On Sat, 17 May 2014 15:06:47 -1000, Geoff Welsh >
wrote:

>George wrote:
>> ('04 Cavalier, 110K miles) Is getting a P0455 DTC. Replaced the gas
>> filler cap; nada. On inspection, there's liquid in the rear fitting of
>> the purge solenoid. (The one in the engine compartment.) I don't see
>> anything else wrong there (like a crack), so maybe the o-ring is
>> leaking?
>>
>> The o-ring is deeply recessed, so changing it would be challenging, even
>> assuming I could find a replacement. Is there some magic sealant or
>> such that I could put in/on the coupling to improve the seal?
>>
>> Thanks
>>
>from SI
>
>P0455
>
>SYSTEM DESCRIPTION
>The control module tests the evaporative emission (EVAP) system for a
>large leak. The control module monitors the fuel tank pressure (FTP)
>sensor signal to determine the EVAP system vacuum level. When the
>conditions for running are met, the control module commands the EVAP
>canister purge solenoid valve OPEN and the EVAP canister vent solenoid
>valve CLOSED. This allows engine vacuum to enter the EVAP system. At a
>calibrated time, or vacuum level, the control module commands the EVAP
>canister purge solenoid valve closed, sealing the system, and monitors
>the FTP sensor input in order to determine the EVAP system vacuum level.
>If the system is unable to achieve the calibrated vacuum level, or the
>vacuum level decreases too rapidly, this DTC sets.
>
>
>from experience, I can tell you that besides a legitimate leak....
>A bad purge solenoid, a bad vent solenoid, and a bad FTP sensor can ALL
>set a evap leak code.
>
>You could take everything apart and test it all manually, or you can go
>to a shop with a good scan tool and a smoke machine.
>
>If there is liquid gasoline in the purge solenoid then the canister is
>ruined, btw.

More or less on the same subject, do you know when the EVAP test is
done? I can drive around for quite a while, city and highway, engine at
temp, ... no light, and my scanner says the test hasn't been executed.
Then it will just pop, seemingly at random.

G

George wrote:
> On Sat, 17 May 2014 15:06:47 -1000, Geoff Welsh >
> wrote:
>
>> George wrote:
>>> ('04 Cavalier, 110K miles) Is getting a P0455 DTC. Replaced the gas
>>> filler cap; nada. On inspection, there's liquid in the rear fitting of
>>> the purge solenoid. (The one in the engine compartment.) I don't see
>>> anything else wrong there (like a crack), so maybe the o-ring is
>>> leaking?
>>>
>>> The o-ring is deeply recessed, so changing it would be challenging, even
>>> assuming I could find a replacement. Is there some magic sealant or
>>> such that I could put in/on the coupling to improve the seal?
>>>
>>> Thanks
>>>
>>from SI
>>
>> P0455
>>
>> SYSTEM DESCRIPTION
>> The control module tests the evaporative emission (EVAP) system for a
>> large leak. The control module monitors the fuel tank pressure (FTP)
>> sensor signal to determine the EVAP system vacuum level. When the
>> conditions for running are met, the control module commands the EVAP
>> canister purge solenoid valve OPEN and the EVAP canister vent solenoid
>> valve CLOSED. This allows engine vacuum to enter the EVAP system. At a
>> calibrated time, or vacuum level, the control module commands the EVAP
>> canister purge solenoid valve closed, sealing the system, and monitors
>> the FTP sensor input in order to determine the EVAP system vacuum level.
>> If the system is unable to achieve the calibrated vacuum level, or the
>> vacuum level decreases too rapidly, this DTC sets.
>>
>>
>>from experience, I can tell you that besides a legitimate leak....
>> A bad purge solenoid, a bad vent solenoid, and a bad FTP sensor can ALL
>> set a evap leak code.
>>
>> You could take everything apart and test it all manually, or you can go
>> to a shop with a good scan tool and a smoke machine.
>>
>> If there is liquid gasoline in the purge solenoid then the canister is
>> ruined, btw.
>
> More or less on the same subject, do you know when the EVAP test is
> done? I can drive around for quite a while, city and highway, engine at
> temp, ... no light, and my scanner says the test hasn't been executed.
> Then it will just pop, seemingly at random.
>
> G
>

No. We don't have state involved emissions testing here, so aren't
always fighting with the on-board monitor strategies. From posts on
iATN I have learned that there can be a lot of quirks on a lot of cars.
Requisite 1 is usually: gas tank between 1/4 and 3/4 full. Next comes
outside temperature not super cold. Beyond that it can be crazy things
like "18 hour cold-soak" or "20 minutes at 50 mph" (which is not even
possible where I live!).

We run the Service Bay Evap Test from the scan tool to verify repairs.

GW