Volvo RWD 900 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 10/2010 900 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

High HC Readings 900 1994

posted by  Townshend Act on  Mon May 6 22:10 CST 2019
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Tue Oct 7 22:44 CST 2014
[RELATED]

Just had my annual state emissions testing completed and noticed the hydrocarbons (HC) readings were a bit high.
At 15 mph, the test results showed a reading of 40ppm (59ppm Max & 25ppm Average). At 25 mph, the test results was 22ppm (34ppm Max & 14ppm Average).
The B230FT passed the test, but the technician commented those HC readings were a bit high.
I've also noticed my gas mileage has dropped off down to 14-15mpg range.
Oxygen Sensor time?
Opinions please.








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    High HC Readings 900 1994

    posted by  Amarin on  Tue May 7 10:59 CST 2019
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
    last visit: Thu Oct 23 22:42 CST 2014
    [RELATED]

    When was the O2 sensor last replaced? O2 sensor should be replaced about every 100,000 miles. Old O2 sensor gives slower response time to any O2 change in the exhaust gas, so that could cause some leeway in AF mixture thus higher HC.

    Amarin.








    •   REPLY TO THIS MESSAGE    PRINT   SAVE 

      High HC Readings 900 1994

      posted by  Townshend Act on  Thu May 9 19:55 CST 2019
      Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
      last visit: Tue Oct 7 22:44 CST 2014
      [RELATED]

      I think the Oxygen Sensor is below 100k miles, but the engine was rebuilt recently after a head gasket failure and tons of coolant having gone down the exhaust pipe.
      The Cat got fouled, but I don't know if I changed out the O2 sensor.
      I guess I'm asking if, all things being equal, is the O2 sensor suspect in this matter?
      Everything else is tight on the engine and it runs great.
      I'm just not happy with the lower MPG and the higher HC's.








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    High HC Readings - to the Volvo 700-900 FAQ! 900 1994

    uid 46171's pic
    posted by  kittysgreyvolvo on  Tue May 7 05:15 CST 2019
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
    last visit: Sat Oct 18 15:23 CST 2014
    [RELATED]

    As CB says with vacuum leaks.

    https://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm#EmissionControlProblemsHighHCCOorNOx

    May be more elsewhere in the FAQ.

    As it is a 1994 940 Turbo (from the factory?) you can check the OBD.

    https://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm#EmissionControlProblemsHighHCCOorNOx

    You are in California, so, you may have factory installed EGR monitored and controlled by the ignition ECU.

    And, well, I dunno write now.

    Hope that halps.

    MacDud.
    --
    Donate NOW! Give your brickboard.com a big DONATION!!! Find the on brickboard pages!







<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.