Decelerating afr's

[Paul C]

when i take my foot off acceleration and allow the car to slow down, what sort of afr's should i be reading with wideband o2 sensor. at present the signal goes really lean?

[Kenneth]

when i take my foot off acceleration and allow the car to slow down, what sort of afr's should i be reading with wideband o2 sensor. at present the signal goes really lean?

yeah, it should go off the scale as your injectors will stop pumping gas into the cylinders (because you don't need fuel to slow down) therefore you have no fuel being burnt :)

[Nutter_John]

Ken is correct the engine should be under 0 load and will be using no boost so the engine is not burning fuel

Will be running mine for the next couple of weeks with a wideband in and will get a baseline before i fit and tune the mapecu2

[Paul C]

Ken is correct the engine should be under 0 load and will be using no boost so the engine is not burning fuel

Will be running mine for the next couple of weeks with a wideband in and will get a baseline before i fit and tune the mapecu2

fit the map ecu2, it doesnt do anything until you tune it. Good to know that the readings are ok.

[Eurospec]

If you hook it up too John, and select your wideband type in the map ecu you will be able to log certain bits from it as std, which will at least alow you to measure normal afr's.

Paul, yeah, when you let your foot off the gas you will see a very lean condition- like 18+ afr, poss off the scale. This is because when you let your foot off totally the ecu will either totally cut injector pulse, or reduce it to a very small amount (rpm dependant).

Cheers,

Ben.