13 replies to this topic

[P91MER]

Ok, started the ol mini up today, even tho it has no throttle cable, and revved it up on the inj unit, and smoke was coming out from behind the engine??? quite alot of smoke infact, could this be due to the exhaust manifold being dodgey?? what is the most likely place it would be leaking from, top of engine, or where the 3-2-1 pipes join the single pipe?

would it most likely to be just the gasket? or something cracked?

Is this a good excuse to buy a performance LCB ?

I went over a rock, which hit all the way down the exhaust pipe, do u rekon this could of caused the problem?

is it still safe to use?

Sorry for all the Q's!!

Rich

[Guess-Works.com]

The most normal place for a leak is at the joint between the manifold and the down pipe. Also I believe yours is a TPI, so will probably have a flexible section in the downpipe before the Cat.

The only course of action is to start the car and feel for the leak ( easier when the car is cold ), and up on ramps

[miniman5]

it depends.... have you hit the exhaust of the road or any thing??? if you have then thats probaly the cause you may have cracked your manifold! so good new fo ryou! you can get a new exhaust but bad new for your wallet

[clubman katie B.F]

look for simple things first, is it the gasket? if so it is an hour job and the gaskets are pence to buy

[clubman katie B.F]

just read your message again....you said smoke????? if you have been messing round down that part of the engine, you sometimes get oil or wd40 on the manifold. this burns off when you start her up giving off smoke.

[P91MER]

I was tinkering around the part the other week, but it is definately exhaust smoke, only comes out when i rev it aswel. quite a blue colour.


as soon as i have got the MOT sorted, and the throttle cable i will check it out on ramps, i have access to some at a mates uncles.. is it still ok to drive?

Rich


and yes, i hit a big massive rock on the middle of the road the other day. if you look at the pics when i fitted the quickshift, you can see the dents it did to the pipe!

if you look at the pipe, and gear linkage, you can see a few little white marks, these are where the rock hit!

[Dan]

Absolutely, there shouldn't be visible smoke coming from your exhaust anyway. Especially on the MPi engine. It is more likely that something is on your exhaust and is burning or melting. Driven over any plastic bags in the road lately? As Guessworks said your exhaust system is flexible and should absorb minor knocks. But if it has failed it is probably the manifold to downpipe gasket, or the screws around the gasket which connect the two. If you did hit a big rock hard though you might have shattered your catalyst, they are very fragile (which is why the system is flexible). So bear this in mind at your next MOT.

**INTERMISSION**

Okay, just read the reply you made while I was writing that. So it seems that this little problem has revealed bigger problems with your engine! You need to find out why there is blue smoke coming from your exhaust at all, which will probably mean taking the exhaust apart anyway. Bobs your uncle, all fixed at once.

[P91MER]

arghhh i am scared now!!

Haven't tried it through an mot yet, as my cable isn't fixed yet, i only started it up the other day to see if the battery was holding its charge.

It could well be that WD40 is on it, i can't remember what day i was workin on the inj unit, and i was spraying WD40 like it was going out of fashion to try and fix the stepper motor on inj unit!

I will leave it for now, got other problems for the mot, like changing headlights, new windscreen etc etc.

so thanks for ya help, and i will look into it ASAP!

Rich.

[tom]

If you have a hole in your exhaust, especially on the manifold, the engine will sound like a tank!

[EVO6RSS]

OK lets clarify the situation.

Is the exhaust manifold leaking/smoking?? Or is there blue smoke coming from the exhaust at the back of the car??

If the manfold is smoking and you have been spraying wd40 on a stepper motor to try and make it work again then this will be the reason. It will smoke like a barstool and smell orible..

As a side note: You will not fix a stepper motor by spraying wd40 on it. A stepper motor is exactly that a motor that opens the throttle to let more air into throttle body when the car is on cold start up.

This is controlled by the ECU. The ecu will have an inlet air temp sensor and a water temp sensor, the ECU will moniter these values and add the additioanl amount of fuel required to start the car on cranking. (Also known as cranking enrichment) and will also have a compensation table that will add additional fuel for cold start up. You will need to buy a new stepper motor. End of story.

Blue smoke coming out of the exhaust: This is a simple one, how long has the car been standing for? If it is a little while then oil will have leaked down the valve stems and will either be sitting in the bores or behind the valves. This is down to valve stem seals and worn valve guides.

Why.. Well the standard rocker gear on a mini ain't great. The design causes side loading on valve train and this is made worse buy poor rocker geomotry settings (the spacers between the rockers which determine which part of the rocker meets the value cap). This is why people fit roller rockers..

So when you start your mini the oil has to be burnt and ends up out the back of the exhaust in the form of blue smoke.. This is nothing to worry about and is very common. When your mini is being run regularly again you won't see it.

The only time to worry about blue smoke is if the engine is on load (i.e canning it 3rd) this will mean the rings are on the way out as you are getting blow by due to worn cylinder walls and worn rings. Get a mate to follow you to make sure and make sure he says it is blue smoke.

Blue smoke - oil
Grey smoke - water/oil
Black smoke - fuel

Hope that helps.

Rich.

[P91MER]

Hello all!! well, i fitted my new cable today, started her up, and presto- no smoke, well ALOT less than the other day!!! so i am guessing it was due to it being standing, it had been stood about 10 days without being even turned over. But the smoke was coming from the back of the engine/exhaust manifold, and i can feel a bit of air when i put my hand at the back of the engine and rev it.

I had taken the stepper motor out, and party stripped it, when i put it back on, i quickley sprayed the terminals to make sure there was no water build up inside, but i also sprayed the potentiometer terminals, and another one towards the back of the throttle body just to make sure there was no water build up.

Also while i was checkin round it today, i noticed a bit of condensation comnig out of the back box, it is a maniflow, and was coming out just where it starts to go bigger for the actuall box. will this get bigger the mor ei use it?

Rich

[clubman katie B.F]

need to be careful when checking for manifold leaks, as there is a lot of air blowing round that area any way from the fan (I hope) another way for checking for leaks is taking the air filter off and sealing the air flow intake with your hand, if the revs don't drop dramatically then it points to a blowing manifold gasket!

[Dan]

The thing with spraying water disperser over ignition parts is that it is only a short term solution or emergency measure. The best thing to do is to keep them all clean. The plastic which ignition/injection parts are made from is naturally repellant to water. If it is clean it will keep damp out all by itself. As they age they get dirty and the dirt is what hold the water. A quick squirt of WD will sort this out but fairly soon the oil will trap even more dirt and things will get worse. This is true of all cars and recently cured what otherwise appeared to be a serious problem with my (eugh) Saxo's :sick: injection system. Give all the parts a clean with a little non residue degreaser and the effect will be much more long lasting.

[P91MER]

what i have done in the past to keep them clean is, spray with WD40, and then give them a quick brush over with a tooth brush!! I so wish it were a carb you kno, if there was only a cheap way to convert it!! I couldn't bring myself to sell her tho, so will have to live with it, and save up for expensive injection mods ie, re mappable ECU, super chip, new throttle body, thats about it!!! the list would be huge if it were a carb!!

Rich

ps, the fan to my car is at the front, so engine blocks most of the air circulating!