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Greg, import technician
Category: Mazda
Satisfied Customers: 7094
Experience:  17 years shop owner import
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2005 mazda tribute: 6,check engine light..catalytic..runs fine

Customer Question

2005 mazda tribute,3.0 v-6,check engine light on,trouble codes po190&po193-fuel rail pressure sensor circuit problem,and p2196&p2198 o2sensor signal stuck rich,banks 1&2.would like to know which of the o2 sensors need replacing,pre-catalytic or post-catalytic.the vehicle runs fine,just need to turn off light to pass emissions test,any clues?
Submitted: 5 years ago.
Category: Mazda
Expert:  Greg replied 5 years ago.
Name is XXXXX XXXXX i will assist you the best i can, please Only accept if you are happy with my answer.

Don't replace any O2 sensor , this problem is due to the P0193 code the fuel pressure is to high , remove the vacuum hose from the fuel rail pressure sensor and check for fuel ,replace if fuel found in the vacuum ., this will cause you your O2 sensor codes

Repair the P0193 malfunction and the others should clear up after the repair , clear codes then retest.

Hope this answer was soon enough that you did not get the o2 sensors, as this would of been a good wast of money.

Kind regards Greg
Greg and 2 other Mazda Specialists are ready to help you
Customer: replied 5 years ago.
hello greg,i did notice the vacumn hose leading to a certain assembly,assuming that is the sensor,was a little dry rotted,is it right at the front of the fuel rail?if it is,i will inspect it like you said.sounds logical,and glad its not the o2 sensors,thanks.
Expert:  Greg replied 5 years ago.

Yes this will be the part if bad replace ,

Get back to me after doing this and let me know .

Customer: replied 5 years ago.
hello greg,well i changed a few vacumn lines in the vicinity,and the fuel filter as well,it was a little clogged,engine light is persistent,vehicle runs fine though,and the o2 codes did not appear any more,could use further insight,thanks.
Expert:  Greg replied 5 years ago.
What codes you you now have after clearing them .

Customer: replied 5 years ago.
hello greg,still have code po193-fuel rail pressure sensor problem.thanks.
Expert:  Greg replied 5 years ago.
Expert:  Greg replied 5 years ago.
Hi again .

Did you check the fuel pressure ?

If not do this then get back to me with the test results ,
One with the vacuum connected and with it disconnected

Customer: replied 5 years ago.
hello greg,thanks for the diagram,is it for the v-6 version?as soon as the owner of the vehicle returns it to me,i will check the fuel pressure,and the correct vacumn hoses,what should the pressure be,around 35-45 psi?that particular part is a dealer/special order part,i would like to make sure that we need it.i will get back with you,thanks.
Expert:  Greg replied 5 years ago.

Yes the fuel pressure should be 34psi connected and 43 psi with the vacuum disconnected.

Regards Greg