emissions question

[wolliver 1]

ok... doing emissions today in class, put the wand thing in the tail pipe and all good. did a few tests like making lean, rich, cold, warm high revs etc...

can someone please tell me why when you disconnect a injector, the hydrocarbons in the emissions go UP. you would expect them to go down wouldnt you?

[wolliver 1]

but then wouldnt they be open when the engine is turned off?

[westy 614]

^^ No fuel pressure??

Edit: What I mean is, if theres no fuel pressure would it matter if the injectors are open???

Edited September 3, 2009 by westy

[mark247 38]

Maybe the other injectors had to put more gas into the other cylinders in order for it to keep idling.. I don't know jack all though! heh!

[*Glenn* 854]

ok... doing emissions today in class, put the wand thing in the tail pipe and all good. did a few tests like making lean, rich, cold, warm high revs etc...

can someone please tell me why when you disconnect a injector, the hydrocarbons in the emissions go UP. you would expect them to go down wouldnt you?

HC's go up because you have less fuel to air ratio which would have previously been set. If you set the CO & HC's correctly, then disconnect an injector, the HC's increase. Its like introducing an air leak.

[wolliver 1]

yup worked it out today, O2 sensor tells ecu engine running lean, so ecu injects more fuel to richen it back to normal. fuel is now mega rich, not all fuel is being burnt, and comes out in the emissions. My lecturer doesnt agree with me, but hey he is a mega douche