m40 overheating and missing engine?? help please

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_bmw_316_lad_
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Sun Sep 05, 2010 9:09 pm

hi all. my 316m40 has started overheating in the past week in traffic and drving, iv recently replaced the water pump,thermostat,fan coupling. i dont believe the rad is blocked as the heater works perfectly fine. i flushed the engine when i done the pump.

also its developed a missfire through all the revs, its worse when the engine is warm, seams like its starved from petrol, replaced the fuel filter but no change?? any help in thses two matters would be great. many thanks Aran.. :D
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eddieg
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Sun Sep 05, 2010 9:11 pm

Fuel pump relay? Air flow meter?
town325i
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Sun Sep 05, 2010 11:37 pm

Have you bled the cooling system properly?
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_bmw_316_lad_
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Mon Sep 06, 2010 4:16 pm

fuel pump is ok and also iv bled the system properly.. any chance the head gasket went?? cant see no oil in water/water in oil. thanks so far for the replies.
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peterjcollins
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Mon Sep 06, 2010 9:58 pm

Hi,
Starting from the basics here, i guess you have checked the plugs and leads are in good codition. I am puzzled that the water pump has been changed along with the thermostat and fan coupling and it is still over heating.
The only thing i can think of that will cause the engine to over heat and misfire is the ignition timing being out.
When you hanged the water pump was the timing belt tensioner disturbed, if so the belt might be loose and jumped a notch on the cam or crankshaft pulley.
The fuel pump relay and AFM would cause the engine to misfire but not necessarily overheat.
Check out the timing and check that the camshaft and crankshaft are set to top dead centre and that the belt is tensioned properly.

I hope this helps
Peter
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