Overrun explained??

[Smoki3]

Can any 1 explain overrun on 16v engines.

Cause of flaming from exhaust..

Cheers

[Stuart]

in the old days when you took your foot off the throttle the buterfly would shut, but air will sill be drawn in due to the engine being driven by the road, cos of the air being drawn in it also drew fuel in and there for made it run rich and pop/bang out of the exhaust (simplified down)


modern fuel injected engines had smart ass bits of code that cut off the fuel when you take your foot off the throttle, thus eliminating the fuel in the engine so it wont pop and bang etc


that help?

[Smoki3]

yea that did cheers, so when is it most likey to happen?

When on full throttle and slowing, or more to the point how will it happen when driving, is there a set revs that it has to be above?

[Stuart]

you have a 2.0 16v?


it wont happen as the ECU stops it.



yes full throttle lift off would cause it. but it wont happen on ecu controlled engines

[Aragorn]

depends on the ecu

my bro's 1.2i pops on overrun with the streight thru ashley on it

and im pretty sure the management system on that engine CANT do coasting fuel cutoff

[Stuart]

modern fuel injected engines had smart ass bits of code that cut off the fuel when you take your foot off the throttle, thus eliminating the fuel in the engine so it wont pop and bang etc


that help?

the spi's arent really that modern :p as it was a half assed appraoch to emissions control

[Smoki3]

it's a 2.0 16v redtop. It pops and bangs (Scorpion straight through system)