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Q: No power. Only uses bank 2 to fire

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Hi guys. I got a 335i. The customer complaints was the engine warning light. I diagnosed the car only to find that it is out of timing, got special tools, I timed the car I started the car all was well then I switched off the car when I started the car again it didn't have power it is misfiring when I unplug coils from 1 to 3 the car doesn't respond when I check the spark it there, I swapped the coils around still nothing, so basically the car is only using 3 cylinders 456. Can it be the MAP sensor on the intake manifold?

My car has 25000 miles.
My car has an automatic transmission.

A: Hi there. It would be helpful to know the y...

Hi there. It would be helpful to know the year of the car in this case to supply the most accurate information. If it were the map sensor, then it would affect all cylinders. Try checking the spark plugs for damage or signs of wear.

Which timing was off, ignition or camshaft timing? I’m going to assume it was the camshaft timing since modern vehicles don’t typically have adjustable ignition timing. Assuming it is camshaft timing, it is very likely the valves in the inactive cylinders have been bent. You can check this by putting compressed air into the cylinder with the piston on top dead center.

This is commonly called a cylinder leak down test. Ideally you should only use about 50 psi. Much more and the piston will move and open the valves. The valves need to be closed for this test to be accurate. If you must use shop pressures of 90 to 150 psi, hold the crankshaft by whatever method you can devise.

Once you have the piston at top dead center with compressed air in the cylinder, listen at the tail pipe, intake manifold with the throttle valve open and in the crank case. Usually the best place to listen in the crank case is by removing the oil filler cap. You are listening for the hissing sound of air passing past the intake and exhaust valves or the piston rings in the case of the crank case. If you here an obvious hiss, you have a leak in one of the mentioned parts.

Bent valves are very common when camshaft timing becomes off. This car has VVT (variable valve timing). With this in mind you should make sure that the camshaft is timed correctly.

If you should require further help getting this taken care of, have a certified professional diagnose the loss of power issue for you so that this can be properly addressed.

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