Long shot?

For the last 4 weeks the my revs have been VERY erratic from 800 to 2500 when just idling. but also at the same time I noticed that the down pip from the engine was blowing a little and was wondering is this could be the issue, as there are no sensor lights on in fact no indication that there is an issue with the engine only the REV counter

Thanks!

Steve

could be a loss of back pressure from the blow causing erratic idle. it would need to be a fairly severe leak to make the car idle that roughly. does it do it when hot as well as when cold? can you see/feel/hear a lot of exhaust gas escaping from the leak? if the leak is due to a gasket failure inbetween the manifold and downpipe then i guess the effect would be greater than for a leak at the flexijoint. i still get the feeling its something else although no lights on the dash is a good sign. does the rev counter work ok when you're driving? does the engine actually sound as though the revs are rising and falling that much at idle or do you think the rev counter could be wrong? does the car still accelerate ok?

Hi!

well i think the hole is in the mesh part of the downpipe (it looks very old) when it is cold it is very bad up and down but when it warms up it does calm down alot. but it still does it but not as much or as bad.

i hear the revs when i drive, when i drive very slowly i fell the enging want to go faster.

the reason im asking is where do i spend the money the exhaust or the enging trouble or will the exhaust fix the issue! knightmare!!!!!

It will be going to a garage but just wanted a feel what could be wrong!

Thanks!

i doubt the exhaust is causing the problem, although the exhaust leak is an mot failure so it'll need fixing either way.

i'm stirring my magic tea leaves and getting the feeling you have idle speed control valve problems (ok its not magic, its common on the 1.2), possibly caused by a faulty/dirty valve or wiring connections on the valve (most likely), or even a failed sensor which contributes to valve control (less likely).

it shouldnt be the lambda sensor, yes a blowing exhaust probably means the lambda will be old too, but the erratic idle is there when cold so count out the lambda. (altho i'd change it with downpipe coz it wont be long)

i'd get the exhaust done at the garage because its a right pain to do at home with a jacked up car, but you can easily do the ISCV yourself. have you got a haynes or do you need a bit of direction? also, dont go buying a new valve just yet, you'll more than likely get away with cleaning the valve and connections.

Hi , had my 2000 Brava for 6 months , stated to rev on its own between 1000-3000 revs for no reason , had a friendly local mechanic :worship: to look at it , but after he'd tried removing and cleaning every sensor he could find he has passed the buck to an auto-electrician friend of his who is coming to look tomorrow ( gonna charge £25 , but got to be worth it ).

After reading everyone of your forum threads , i'm sure he'll find its the idle control valve or stepper motor . Its been so annoying :bang: because it drives fine apart from this piggin' revving ( they think i'm a boy racer at traffic lights ).

Lets hope he finds out what it is and its not gonna cost too much !

I will let you all know .

My Auto- electrician has found the fault !!

After plugging in his computer and resetting the history , he ran the engine and came up with a problem with the Air pressure sensor . (top of the engine opposite end to the distributor) He removed it and it was dripping in engine oil ( its supposed to be dry )

The whole problem was there was too much engine oil in and it was splashing on to the sensor and clogging it up telling the ecu that the pressure was wrong therefore all the other sensors were compensating for this and buggering up the tickover .:idea:

He romoved about 1/2 litre of oil , (halfway up the dipstick )cleaned the sensor and now it runs like a purring kitten , tickover exactly 800 rpm

I was nearly at the stage of buying new stepper motor and other sensors :bang: , but this bloke charged £40 , a bargain !

So if your Brava is running like a mad rabid dog , check the oil first

Hope this helps someone

if you overfilled by half a litre or more then you may have damaged oil seals if you drove like that for a while. how many miles did you do between overfilling the oil and getting it drained?

i'd ask how you managed to overfill it in the first place but there's only one answer

I only changed the oil two days before the problem , so .......about 30 miles or so .

Theres no damage i can tell it runs fine with no smoke or anything . :worship:

I filled the oil to the top of the dipstick but now its just under half way so thats something to remember , got the MOT tomorrow so any deep down problems with emmissions and stuff sould be picked up there .

Stay Tuned for any updates ! :slayer: