1996 NISSAN MAXIMA , LOST GAS CAP, CHECK ENGINE LIGHT CAME ON

On 1/13/2011 7:46 PM, Tegger wrote:
> Steve > wrote in news:4d2f907c$0$17966$38cefb40
> @news.westelcom.com:
>
>> On 1/12/2011 7:46 AM, Tegger wrote:
>>> Steve > wrote in
>>> :
>>>
>>>> On 1/12/2011 7:02 AM, Tegger wrote:
>>>
>>>>>
>>>>> I just studied some late-model EVAP diagrams I have access to, and
>>>>> there is indeed no separate pump, so engine vacuum can only be the
>>>>> source of testing vacuum, as you say.
>>>>>
>>>> A lot of the late model stuff is natural vacuum leak detection. Done
>>>> with engine off.
>>>>
>>>
>>>
>>> How do they do it?
>>>
>>>
>> Vent is closed. As gas fumes contract and fuel cools a slight vacuum is
>> pulled in the tank. This closes a switch.
>>
>
>
> Considering the current system can detect the very tiniest of pinholes,
> what's the tolerance? How long does it allow for vacuum to leak-off before
> it decides there's a problem?
>
>
If switch does not close P0456 sets. The test runs right after shut
down. My service info doesn't give a time limit. This is for a Mopar.

Steve Austin > wrote in
:

> On 1/13/2011 7:46 PM, Tegger wrote:

>>>
>>
>>
>> Considering the current system can detect the very tiniest of
>> pinholes, what's the tolerance? How long does it allow for vacuum to
>> leak-off before it decides there's a problem?
>>
>>
> If switch does not close P0456 sets. The test runs right after shut
> down. My service info doesn't give a time limit. This is for a
> Mopar.



Thanks.


--
Tegger