414i poor mpg & performance - skreech
My rover 414i has been for an mot and has failed on the emissions. also i get poor performance and mpg, and the engine will some times idle a bit unsteady going up and down. The car will run ok it just seems to have very poor acceleration power.


Edited by Pugugly {P} on 30/12/2007 at 18:56

poor mpg + performance - Screwloose

Is it running on all cylinders? Idle control systems can mask a single-cylinder miss - listen to the exhaust for a even flutter.

What were the emission test figures? Both natural and fast idle; CO, HC and Lambda.
poor mpg + performance - skreech
I will check for a cylinder miss , the power loss is quite significant , lambda is 1.045
(co fast idle 0.82% , hc fast idle 320ppm, fail) (co natural 0.45% pass).
poor mpg + performance - Screwloose

The HC figure shows that it's not likely to be missing on one cylinder. It's seriously rich; so things like the coolant temp sensor and the MAP pipe to the ECU are your first checks.

Any sound of exhaust manifold leakage?
poor mpg + performance - skreech
temp sensor ok resistence seems to be in limits. and map pipe ok. there is a slight hissing but it seems to be coming from around the intake area. and recently i've noticed a slight
whistling sound. engine surging is intermittent. I will check the ex manifold tommorrow for leakage. the car just doesnt have the proper sound to the engine when driving. thanks again steve..
poor mpg + performance - scrapmetal
Is the timing ok? if the exhaust cam is one tooth out it will fail emmissions.
poor mpg + performance - skreech
thanks for all the help so far, I'll check all the above when i get achance.

Ask Honest John

Value my car