Engine & Gearbox EGR valve and hesitation - what really happens?

Discussion in '6th Generation (1997-2002)' started by Stew Pot, Saturday 27th Apr, 2013.

  1. Stew Pot Member

    Sorry, can any one on here please give a good description of an EGR's activity during loaded driving.

    My 2000 Accord (1850cc) feels sluggish under acceleration.

    I read a Haynes manual that says the EGR should be doing it's thing under load, however, when I monitored my EGR activity, it was only busy at very very light load.

    Once I give the car any work to do at all, the solenoid activity ceases.

    I then read elsewhere that if the EGR ports are clogged it won't effect drive-ability.

    Well, the configuration of the EGR valve is such, that it is normally closed, so no pulsing activity on the solenoid = valve closed, (which simulates EGR ports - blocked, so shouldn't effect drive-ability).

    If all that is true, i.e. clogged ports don't effect drive-ability, (possibly just some pinking or misfire), then I'm confused.

    There seems to be two conflicting theories floating around.

    I know that my EGR valve is closed when there is no activity on the solenoid because I have had it out and pulsed it manually with a 110Hz 12V PWM @ 35% duty, then watched it close when the signal is removed. I can even hear it hitting hard against its seat when I manually pull open the pintle then release it under its own spring pressure.

    So to summarize, does anyone have any live data of their EGR valve activity under hard acceleration? Is it really quite active under high load conditions?

  2. Ichiban Founder Staff Team

    England CJ Leeds
    Can I ask how you measuring the EGR activity now to come up with those readings? any DTC stored on the ECU?
  3. Stew Pot Member

    With a scope on the PINK wire.

    I can't find a scanner to fit the 5 pin OBD connector, so I have no idea.

    I have since programmed an Arduino to mimic the same pulse, by outputting the same PWM frequency and duty, and included a push button to manually activate the EGR while driving. It turns out whether active or not, there is no noticeable different in the drive-ability whatsoever. I know the EGR is doing as it's commanded when I use the Arduino, (the connector plug to the ECU is completely removed during manual operation). The ultimate proof of it's operation is it stalls the engine completely at idle, when I switch the valve full open.

    Back to the drawing board. It's all good fun until I fry the brain :Smile: