Volvo AWD Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 7/2020

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

Can IAT sensor (intake air temp) cause no run condition?

uid 51415's pic
posted by  andybbrown on  Wed Apr 29 12:03 CST 2015
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Fri Oct 24 06:08 CST 2014
[RELATED]

Could the loss of this sensor (broken wires) cause over-rich no run condition?
Also, do you think the little wires and maybe a bit of plastic could get sucked up into the throttle?









  •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

    Can IAT sensor (intake air temp) cause no run condition?

    posted by  KlausC on  Wed Apr 29 19:21 CST 2015
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
    last visit: Fri Oct 24 10:15 CST 2014
    [RELATED]

    I never say never. It is possible that at wide open throttle, things that large and light could get sucked into the intake manifold. Broken wires might even make it into a cylinder where they would be immediately incinerated. The larger plastic would be stopped by the small opening of the intake valves.

    Why do you think the sensor was ingested? Could it not just be knocked off and laying on the ground somewhere?

    The missing IAT and subsequent hole would not cause a no start. Allowing a lot of unmetered air into the system would initially cause a lean condition, followed by an ECU over correction and a rich condition. This will slowly coat the spark plugs with fuel and eventually cause the engine to stall due to covered spark plug electrodes. Also not good for the cat converter.
    --
    My back feels better when I sit in a Volvo seat








    •   REPLY TO THIS MESSAGE    PRINT   SAVE 

      Can IAT sensor (intake air temp) cause no run condition?

      uid 51415's pic
      posted by  andybbrown on  Wed Apr 29 21:42 CST 2015
      Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
      last visit: Fri Oct 24 06:08 CST 2014
      [RELATED]

      My car is running very rich. I can smell the fuel and it stalls. I have cleaned the crankshaft sensor, changed the camshaft sensor, rechecked timing at crank, checked throttle body and hoses. Next will have to be the MAF (air mass meter) but the thing is when I unplug the MAF nothing really happens much with the engine. It certainly doesn't run any better with or without it. Only once it stalled after pulling plug and one time made a sound like gobbling air. The car is starving for air.








      •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

        Can IAT sensor (intake air temp) cause no run condition?

        posted by  KlausC on  Thu Apr 30 09:20 CST 2015
        Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
        last visit: Fri Oct 24 10:15 CST 2014
        [RELATED]

        Any unmetered air entering the intake manifold will do two things: It lowers the vacuum pressure which can then cause the fuel pressure to rise, and the 'lean' condition often causes the ECU to alter timing to create an over rich condition.

        I do not know what the default is if the IAT sensor is not working. The MAP sensor is also in the same location and the default for that is zero pressure.

        I do not think the MAF is bad, but you should check the wire connectors. BTW, never disconnect/connect the MAF while the engine is running.
        --
        My back feels better when I sit in a Volvo seat







<< < > >>



©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.