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car is hard to start in morning and smell of exhaust fumes !

Posted: Sat Jun 25, 2011 12:31 pm
by matt_320i
hi my 320ise has a starting issue basiclly she wont start unless you give it a fair bit of throttle and when it does its almost as if it dies like its out of petrol and then picks up to normal i hjave checked the afm pipes and they are ok and not split and alos a strongish smell of exhaust fumes has occured in the car had checked the exhaust system and that is ok can any1 help?

Re: car is hard to start in morning and smell of exhaust fum

Posted: Sat Jun 25, 2011 3:16 pm
by Grrrmachine
I'd expect the blue temp sensor. A fault there would lead to overfuelling and hard start.

Search on here for how to check it, it's a known fault especially of M20 engines, and has been covered countless times.

Re: car is hard to start in morning and smell of exhaust fum

Posted: Sat Jun 25, 2011 4:51 pm
by matt_320i
thanks i dont know how to search for it on here can any1 help on how to check it ?

Re: car is hard to start in morning and smell of exhaust fum

Posted: Sat Jun 25, 2011 6:14 pm
by matt_320i
i found a little blue plug near the inlet manifold so i pulled it out and started it to see if it made a difference and it didnt so i dont know whats wrong wiv it :(

Re: car is hard to start in morning and smell of exhaust fum

Posted: Sat Jun 25, 2011 6:20 pm
by Green
That sensor tell the ecu what the water temp is and according to its reading chucks in more or less fuel. If it's kaput it will overfuel and run like crap, removing the sensor and things stay the same could well verify that it needs replacing (Although doing a test on its reading would be more accurate).
It's like £15-20 from euro car parts, it probs been there a while now and might as well be changed.

Re: car is hard to start in morning and smell of exhaust fum

Posted: Sat Jun 25, 2011 7:22 pm
by Grrrmachine
To test it properly you need a multimeter, even a cheap 2 quid one from the market will do. That little blue plug you found only has two pins on it; switch your multimeter to OHMS (resistance) and measure it when the engine is cold. Then go for a drive, get the engine hot, then measure it again.

At cold, it should measure about 3000 Ohms, and at hot about 300, give or take. It doesn't matter what the actual reading is, it matters that it changes as it gets hot. If it doesn't, the engine constantly thinks its cold, and overfuels (like a choke on an older engine).

Don't just swap parts out until it works; learn to do the tests and LEARN TO SEARCH. There's 7 years of good info on this forum, that a tiny amount of work will help you discover.

Re: car is hard to start in morning and smell of exhaust fum

Posted: Mon Jun 27, 2011 9:46 pm
by KimH
My blue sensor seemed to be roughly within spec but, to diagnose the problem, I got a spare sensor and simply connected it to the plug and laid is on top of the thermostat housing. It did the trick and proved the original was goosed. I fitted it properly soon afterwards.

That blue sensor has so much impact on how the engine runs. For the sake of £15-£20 it's got to be worth a try.

Re: car is hard to start in morning and smell of exhaust fum

Posted: Tue Jun 28, 2011 12:41 pm
by mattqf77
Also try cleaning ICV valve next to throttle body - clean it with carb cleaner.
Had same problem with my car - changed blue temp sensor, cleaned ICV and now car starts first time, every time..