1998 S70 P0171 vacuum leak, bad hoses 9155862 Topic is solved

[goVolvo]

Thanks. Very good pics for vacuum lines. Also is the short-term fuel trim and long-term fuel trim number the best indication of vacuum leak? Is the normal OBDII reader capable to scan these numbers?

Last month it passed emission test with the old way: I rev up the engine to about 2500RPM and hold for several minutes, and exhaust air is measured at the tail pipe. If it was running too rich it could have failed the emission test.

Anyway it also idles a little rough sometimes. Seems also points to vacuum leak.

Sorry for being lazy and not getting back to this. My problem was solved. It was not this elbow but couple of other rotten vacuum hoses. I am lucky they are around the vacuum hose tree and is easy to access. I replaced the hose from EVAP canister to intake manifold, and also the one from air box to vacuum hose tree. No more error code since then and the engine runs happily.

[rugbygrrl_15]

Hi everyone,

When I dealt with dreaded P0171 and it’s various cousins buggering up the fuel/air mix it was all about replacing the worn out vacuum lines/hoses. I recommend even if you get things set for this year’s smog check, work your way through replacing all the lines/hoses, especially if you live somewhere hot and arid like me.
Don’t forget to make sure the silver valve at the top of the engine it has the purple vac line gets replaced too, mine quit at about 150,000.

Volvo club uk has a shite ton of information and diagrams. Some is free to access other parts of the website you need a membership. Pelican Auto Parts, FCP Euro, and IPD have lots of good photos, diagrams, videos, and guides. Never forget this trick a librarian taught me to do when doing an internet search: if you write topicYourSearching filetype:pdf
You will only get results that are pdf format, which most information from VADIS or repair manuals are posted on the internet. If you’re like me then look at your search results in the images tab and you maybe able to scan through the thumbnail images for what you need.

Good luck and happy hunting
S

[rugbygrrl_15]

Hi everyone,

When I dealt with dreaded P0171 and it’s various cousins buggering up the fuel/air mix it was all about replacing the worn out vacuum lines/hoses. I recommend even if you get things set for this year’s smog check, work your way through replacing all the lines/hoses, especially if you live somewhere hot and arid like me.
Don’t forget to make sure the silver valve at the top of the engine it has the purple vac line gets replaced too, mine quit at about 150,000.

Volvo club uk has a shite ton of information and diagrams. Some is free to access other parts of the website you need a membership. Pelican Auto Parts, FCP Euro, and IPD have lots of good photos, diagrams, videos, and guides. Never forget this trick a librarian taught me to do when doing an internet search: if you write topicYourSearching filetype:pdf
You will only get results that are pdf format, which most information from VADIS or repair manuals are posted on the internet. If you’re like me then look at your search results in the images tab and you maybe able to scan through the thumbnail images for what you need.

Good luck and happy hunting
S