codes po171/po174
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codes po171/po174
I have a 99 ford 250 the codes 171 and 174 keep coming up when the fuel tank is toped off. The codes are sys adaptive fuel too lean bank1 and bank2 any ideas where to start to fix the problem?
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Joined: Jan 2002
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From: USA
Keith W ,may be on the right track.Let me explain
The codes your getting are secondary codes as a result of a rich condition first.
This means the pcm is seeing a rich condition firts and adjusting the computer all the way lean to compensate for intial rich condition .
If you are filling the tank to the top with no room for expansion in heat the fuel will actually expand and fill the evap canister with fuel.which means when it purges the evap canister by the purge solenoid valve it will cause a rich condition.
Then you have the senairo I explained above.
Hope this helps
Remember this only the problem ,if it happens every time you fill the tank.
If you are getting these codes at other times ,it could be a true lean condition or a vacum leak somewhere.
Rich
The codes your getting are secondary codes as a result of a rich condition first.
This means the pcm is seeing a rich condition firts and adjusting the computer all the way lean to compensate for intial rich condition .
If you are filling the tank to the top with no room for expansion in heat the fuel will actually expand and fill the evap canister with fuel.which means when it purges the evap canister by the purge solenoid valve it will cause a rich condition.
Then you have the senairo I explained above.
Hope this helps
Remember this only the problem ,if it happens every time you fill the tank.
If you are getting these codes at other times ,it could be a true lean condition or a vacum leak somewhere.
Rich
