Hi All,
- 2016. Failed MOT on emissions. Replaced catalytic converter. Passes MOT. Given back to me and the exhaust acoustics are much louder. On the way home the car cuts
- Towed home. Fires up but chases idle (exhaust acoustics sound like a revving tank)
- After a few drives the acoustics start to increase again. I find that the new MAP sensor hose connector (straight design) has been slipping off so I replace with an right-angled connector which offers a tighter grip.
OK here's my 2p worth.....
I wonder if the exhaust sound is a clue. If you've got a leak in the exhaust manifold, the Lambda readings will be all over the shop.
Going up hills could be exaggerating this as the engine will be under more strain & flexing the whole system making a leak worse.
If you've got the standard exhaust / inlet system, the downpipe bolts on just under the lambda sensor, so I'd be tempted to check around there. Easiest to do if the front's on stands / ramp & the engine's cold (so you don't burn yourself). You'll need to get underneath and behind the engine to see the downpipe, but be able to feel any leak blowing on your hand if you hold it close to the joint & check all around. Obviously this area warms up quickly, so don't touch any of the pipes.
The exhaust noise in the engine bay will be noticeably more than usual when you rev, so you could try that before fumbling around from underneath.
Otherwise, do try and get it looked at by someone on here with a scanner & a bit of experience. It will save a lot of hassle (and money probably).
Most mechanics are honest, but the SPi is a bit of an enigma and I'm sure someone in the local mini community would be more than happy to take a look.
Good luck!
MA