I was driving back from Wembley to Bracknell the other day, wife and nipper with me, when the exhaust started making a racket. Sounded like I had a V8 with a big bore exhaust! I thought the worst, so limped home, with the intention of paying big bucks to the guys at Kwik-Fit the next day.

I called into Kwik-Fit, who put the car on the ramp and saw that a blanking plate just in front of the catalytic convertor had fallen off the down pipe! I never knew that there were blanking plates on the exhaust system, but the man welded a short bolt in the hole and job was done! I gave him a tenner for his troubles, as he couldn't put the job through the books (there ARE some honest Johns out there after all!) .

So, if your engine starts sounding a tad loud, don't suspect the worst and make sure you check the car with the exhaust mechanic. You might not get an honest guy like I did (he was the shop manager too!).

BTW, the plate was on the left hand side of the pipe.

Initially, I thought the noise was a result of having removed the catalytic convertor heat shield a few weeks ago. The weld had broken on one side, resulting in the shield dragging on the floor. Fiat advised me to remove the shield, but avoid parking over dry grass after a hard drive!

Glad to hear it's sorted easily and cheaply!

I hope that wasn't the lambda sensor hole he's just filled in!

i was thinking the same thing hellcat, ive never seen a blanking plate just in front of the cat, but there is a lambda sensor in the exact same place. maybe he has an aftermarket exhaust with a blanking plate i dont have?

jug said:

i was thinking the same thing hellcat, ive never seen a blanking plate just in front of the cat, but there is a lambda sensor in the exact same place. maybe he has an aftermarket exhaust with a blanking plate i dont have?

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Now you've got me worried! I know roughly what a lambda sensor does, but where does it connect to on the engine? Presumably I have a wire trailing from a connection point on the engine somewhere. There was nothing hanging down around the exhaust area, when we had it up on the ramp.

As I see it, the sensor provides an automatic means of adjusting the fuel input to the block. What could the short term adverse effects be here? I guess long term, the car could fail MoT on emissions

Ho hum, if it IS the sensor hole, its going to be a pain removing the welded bolt!

the lambda sensor is basically an oxygen sensor that allows the car to determine the fueling and ignition timing required to ensure complete combustion (along with several other sensors). it looks a bit like a spark plug. if it had dropped off you should be able to see it hanging on a white wire. the wire goes up into the engine bay and connects to a multiplug under the small black plastic cover right at the back of the engine bay, in the middle. wish i had a pic coz thats a poor description. if it has dropped off you will probably have an overfueling situation which spells doom for your cat, and yes an MOT emissions failure. you should look under your car for the welded bolt and see if there is anything near it that has a wire connectd to it, if there isnt anything on your exhaust that fits that description then you can be sure of two things, 1. you're missing a lambda sensor 2. you CAN get better than a kwik-fit fitter.

in fact while we're on the subject no one should ever go to quik-fit under any circumstances. even if you get a million pound quik-fit voucher for xmas, just burn it. it'll be cheaper in the long run. i really hope you still have a lambda sensor on your exhaust, if you dont we've entered a whole new era of quik-fit funk-ups. it is a great story to add to my collection tho, let me know how things turn out.

Above 70% throttle the ECU ignores the lambda sensor switching to a static map. There is a number of technical reasons for it. The very same happens when the ECU can't get a reading or a totally wrong reading. This wouldn't destroy the cat.

Well, not had time to look for any trailing wires yet, will do that tomorrow. Anyone know how long the cat will last without sustaining irrepairable damage? I hope to get the situation fixed next weekend.

Also, how is that sensor held in place on the exhaust pipe? Is there a bracket that holds it in place, or does it 'screw' into the pipe directly? If the latter, I would imagine that the hole threads are knackered.

I hope I find the sensor hanging somewhere in the engine, although I'm not holding my breath, as I didn't see it when the car was on the ramp.......

Anyone know the sensor type for the Brava 1.8 ELX (1999 model)? How many wires, and what configuration?

Panic not, lots of cars have a separate threaded hole in the exhaust before the cat so Fiat could bung a probe in for diagnostics.

Chances are the Lambda sensor is still plugged in and working, especially if the car's running ok and getting sensible mpg.

If your car is not thirsty and you're getting normal mileage per galon, also if the car runs smoothly as normal all the time then you're on the safe side and your lambda sensor is still alive and kicking....

diagnostics probe access sounds like a likely explanation, i've seen similar things on other cars. good thinkin fixitagaintomorrow i didnt think of that.

the last time i had a broken lambda (last november) the ecu overfueled so excess fuel vapour collected in the cat, then when the cat got hot it ignited the fumes and made my cat burn, when i looked under the car the cat was glowing red like hot coal, i could see the glow even in daylight. the smell was awful. when i removed the cat it was brittle and fell apart in my hands.

i agree that the car will use the default parameters when the lambda fails, and the lambda makes bot all difference when engine is cold or under hard acceleration, but the default paramaters cause an overfueling condition which can destroy your cat if excess fuel collects in it. i dont know how long the lambda was broken before the cat died, i bought the car with a duff lambda and 2 weeks later the cat was glowing. there is still a faint mark on my drive where the car was parked with the glowing cat, its a kind of bronze stain.

Well, Fiat at Slough put the car on the ramp this morning, and I'm glad to say that the Lambda sensor is fitted and working well. The lambda probe exhaust entry point is WELL up the down pipe, right next to the block.The miscreant hole in question WAS indeed the inspection/probe hole, 3 inches in fron tof the catalytic convertor, and they tell me there is no need to de-weld the hole. If it holds, all will be well.

Really pleased, as wasn't looking forward to costly repairs!

hooray! oddly enough my lambda is fitted in the hole 3 inches in front of the cat, and i dont have any inspection probe hole anywhere.