Announcement

Collapse
No announcement yet.

Inconsistent AFR poor MPG

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
  • #1

    Inconsistent AFR poor MPG

    Had our DS3 110DSport for about a year and never been convinced that fuel economy or performance was quite right. It's been back to Citroen a couple of times but they never found anything. So I decided to get an ODBC reader and monitor what was going on.

    Using dashcmd to log, Boost, AFR, load and Temp I have noticed that at cold start AFR is around 15, then after about 1-2 minutes it goes to 29.0 and performance is poor. However if I stab the throttle the AFR will reduce to anything from 15-26, if it stops around 22.0 when on cruise the MPG seems to improve and 65-70 mpg indicated at 70mph. However every time the throttle is released AFR returns to 29.0 and will never recover unless throttle is pulsed. Reported Boost responds with throttle to typically 3-6 psi on cruise.

    Car is stock map with DPF EGR etc.

    What should the AFR be on cruise?
    Is this normal behaviour?
    Do I have a vacuum leak or other problem?

    Can anyone help?

    Regards

    Chris
    Tags: None
  • #2
    what MPG are you getting? how long is your journeys? what roads do you drive on?

    also wtf is afr.
    sigpic.

    | DStyle Nav 1.2 PureTech 110 |
    Third time around.
    Work in Progress

    Comment

    • #3
      Average over last 6000miles is 50mpg mixed driving. On short journeys it does 40mpg on long journeys if driven slow it will get mid to high 50's.

      AFR is Air to Fuel Ratio, ie the fuel mixture the ecu is trying to achieve.

      Comment

      • #4
        Sounds alright to me? The mpg Citroen claim for pure motorway driving on the 110hdi is 70mpg and we all know how unlikely it is to achieve that in the real world
        sigpic.

        | DStyle Nav 1.2 PureTech 110 |
        Third time around.
        Work in Progress

        Comment

        • #5
          I have the 115 eHDi (same engine I think) and my MPG varies between winter and summer. It drops off a bit in the winter and improves again in the summer, the dealer told me this was normal. Over the winter I averaged 52mpg with a mix of 22 mile commutes to work and 200+ miles every other weekend.

          As Rickzayne said above your mpg doesn't seem to bad and it's hard to judge without knowing your driving style and whether you have your AC on all the time etc.

          My current MPG is 54.2, that's with spirited driving and the AC on all the time, on motorways it's around 59-60mpg.
          sigpic

          Comment

          • #6
            Never thought I'd see the day when somebody feels wronged by getting 40-50mpg O.O
            cyclone> Fish is the man

            Comment

            Previous template Next
            Working...
            X