Fumes!

[axshack]

Hi all, today I did an 80 mile each way journey in the Midas.
I am now suffering from Carbon Monoxide poisoning!! When I crack open a window the car fills with fumes. It still does, to a lesser degree, when the windows are closed!

Anybody have any ideas why this might be?

Is there a solution? I hope so, because right now it is positively dangerous!!

Cheers
Dave

[streetsy]

if you are travelling at any kind of speed the air passing by the car at higher pressure/speed Will draw lower pressure air out of the car creating a slight vacuum, if there is a hole (perhaps a split gearstick gaiter) air and fumes may be drawn into the car from the exhaust tunnel below.

[Hans Efde]

Are we talking mk3 Midas? Then it's clear engine bay fumes enter the cabin. Ofcourse gators etc (steering column, electric wiring, heater hoses) in the bulk head need to be intact. But I would guess the rubber on the ventilator unit doesn't touch the bonnet. This should be a sealed connection so the air from outside can enter the ventilator and into the cabin. If there is a gap between the rubber and the bonnet (is the rubber installed anyway or missing) engine bay fumes can enter the cabin freely.

[axshack]

I will check this out, but I think that the majority of the fumes are being dragged in at the rear. Must admit I never reckoned the heater air intake might be the problem! the seal is there, but is old now and might not be sealing. I have the heater system, inside the cabin, in pieces as I am about to change the matrix, maybe that is the problem? time to do some sealing I reckon !

[Hans Efde]

I can't believe fumes come from the back. The only holes should be the vents near the taillights. There should be holes in the back plate and inner walls so the cabin air can be extrcacted via these holes. The vents are far away from the exhaust so can't be the problem.

[midasnut]

I had similar problems, to a lesser degree on both of the Mk3's I've owned. I found the problem worse if I opened the sun roof. On both of my cars altering the exhaust angle and length improved the problem. On the first car I put a deflector pipe on to point the gases down, this helped but didn't fully cure the problem (it fell off). on the second car I extended the exhaust past the rear of the car. Again this worked but I couldn't leave it in place because it was sticking out too far and I kept walking into it. Neither of my cars had the two holes Hans mentioned near the rear lights.

[Jin]

I’m glad I’m not the only one that has this problem - and mine is a mk4
I too suspected the heater intake so i isolated it by taping over it and covering the opening with cling film - made no difference
my exhaust stinks anyway - something I’ve still not resolved but it did pass the MOT, the engine bay doesn’t smell of anything much, being a k series its well sealed and emission controls keeps it sniffing its own arse all the time.
the smell i get in the cabin is the exhaust, yet the system is sound and i have no ventilation at the rear or anywhere for that matter yet it still happens, I actually keep the fan on constant to help the situation by pumping fresh air into the car, eventually I may well find the issue but it has evaded me so far.

[streetsy]

If you suspect that the fumes are entering via the heater blower unit in the engine bay, are your breathers connected to the inlet/carburettor or venting to atmosphere. If it is the latter there may be extra fumes in the engine bay, connecting breathers to the inlet may reduce fumes but would not of course re-seal the air inlet.

[axshack]

My breathers are connected to the inlet/carb. I think I will take the pancake filter off and put the factory unit back on !! that might help! also going to put a new lip seal on the air intake for the heater blower...and...renew the LCB exhaust manifold, as well as get the very rich mixture of the carb sorted out.
Next question: For the MG Metro engine which is the best, preferably stainless steel, LCB manifold to use?

Thanks in advance folks !

[Hans Efde]

Yes medium size LCB works fine. Be aware of the size difference of Mini and Metro LCB's. I bought this one:http://www.twinkam.co.uk/shop/article_SC001/Stainless-Steel-LCB-Exhaust-Manifold.html?sessid=fRQuTMF2NKcTMqkT0uzUFWHx9bpiqBQoZnHpKSYAlQiDnoFu4YQlHea6t9SwmjUM&shop_param=cid%3D1%26aid%3DSC001%26

Which is a great exhaust for the money. BUT it is for a Mini. It fits but is 1 inch longer, so it sticks out the bottom of the car. Check out this pic and further for details: http://i1094.photobucket.com/albums/i444/midasracer/Midas%20forum%20matters/IMG_4552.jpg
If you want to prevent this, specifically by a Metro LCB.
For any LCB you buy, it may be handy if it has nuts welded on for fitting of a lambda probe (as you see on my exhaust). I bought a wide band lambda kit with gauge and you'll never have to guess anymore about how your carb is running.