• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

940 Hesitation on take off

hessam69

Well-known member
Joined
Jun 19, 2009
Location
Sydney, Australia
Hi,

I have a 1993 940 with B230FB engine with LH 2.4 AW71.

I have always had a problem with the engine where the car runs well, however more than half the time, when I go to leave the traffic lights, the engine stumbles/hesitates for half a second before going smoothly. The idle is very smooth though. Also when starting from cold, the engine idles quite roughly for the first five or so seconds, then it is fine after that. Once warm, no idle issues.

I have replaced all the vacuum lines, serviced the throttle body, replaced the entire PCV system, spark plugs, spark plug leads, checked the coolant temp sensor, replaced the RPM sensor, fuel pump relay, adjusted the TPS, checked the FPR, tried three other AMM with no diffference, I am now out of ideas for what else to check. There are no fault codes. The engine drives as normal other than this issue. There is plenty of power, no other complaints at all

Thank you
 
Acceleration is helped by the fuel pressure regulator on the fuel rail. I would suggest a fuel pressure test. If the pressure is a bit high or low. That can cause some hesitation. Another though t is to check the intank pump. On your car there should be a test port in the large fuel hose going to the main pressure pump in the tray. It uses the same kind of shrader test port as the fuel rail. When was the last time the fuel filter was changed? Maybe one of those smoke tests for the intake to double check for vacuum leaks?
 
Back
Top