Engine shakes at start up and cuts off when braking

[Learning]

Good day fellows,

These last couple of months my 318i would shake for about 45 seconds after start up and then stabilize. But, it hasn't been happening after every start up. Only few times a week.

Today, I was driving and the CEL came on and after about 35 minutes of driving in a hot weather my engine suddenly stopped while driving on the freeway during rush hour and so I pulled off, parked on the shoulder, tried to start the car 5 times. It cranked and shook, but wouldn't start and so I thought the engine must have been gone. However, after about 3 minutes I tried to start again and it did start. The RPM would be running up and down between 500 RPM and 1000 RPM. And now when I'm driving and suddenly brake, the engine would cut off and so I started the car while it's still coasting. The faulty check engine light code is 1222 which is the O2 sensor (which is the same code I've always been getting most of the time with other problems). What could be the problem?

Years ago I had a similar problem but only braking and engine would cut off (no shaking after start up). I then replaced the idle speed control valve and it fixed the problem.

Could it be the same problem now?

[grippymonkey]

check your vacuum hoses... the hose from my intake boot to the lower intake manifold portion was torn. Also the rats nest of hoses under the intake manifold are an issue.

Usually that is what it is. When you are on throttle you can keep it running, but when you get off the throttle the rpm's will drop too low and kill the car.

[jaywood]

I'd say vacuum leak as well. Check all your hoses. If you can hear any leaks, use a long tube to hear exactly where the leak is coming from.

[Learning]

Are the leaks easy to hear when engine is running?
Is there a simple and easy visual test to see if there is a leak?

[jaywood]

Just listen for it. You can hear it

[Learning]

Today in the morning, I started my 318i and opened up the hood and sure enough I heard a hissing sound. Took the car to a mechanic who did a test with a smoke generator unit and we found a big crack on one the top hoses adjacent to the idle speed control valve. We replaced the cracked hose and I started the car but it was still shaking and the CEL was still on. We then did a second running of the hoses with the smoke generator and found a small leak near the edge/underneath the clamp on one of the hoses. Since I was in a hurry we taped around the leak with a black tape and I started the engine. This time it was much better only the engine is running a bit rougher than normal and the CEL would come on only once in a while. I wonder why taping around the leak wasn't good enough to seal a small leak?

[Eecen]

More vac. leaks?

[grippymonkey]

Today in the morning, I started my 318i and opened up the hood and sure enough I heard a hissing sound. Took the car to a mechanic who did a test with a smoke generator unit and we found a big crack on one the top hoses adjacent to the idle speed control valve. We replaced the cracked hose and I started the car but it was still shaking and the CEL was still on. We then did a second running of the hoses with the smoke generator and found a small leak near the edge/underneath the clamp on one of the hoses. Since I was in a hurry we taped around the leak with a black tape and I started the engine. This time it was much better only the engine is running a bit rougher than normal and the CEL would come on only once in a while. I wonder why taping around the leak wasn't good enough to seal a small leak?

sounds like it's time for an overhaul of hoses since things are getting better one by one

You can also reset your ECU once everything is replaced. That will usually give you a fresh crank.

[Nairb]

I agree with grippymonkey.. if you care about the life of your engine it's time to replace the hoses. Honestly, it will not take that long, and once you do it, you will feel very familiar with your engine, and will drastically reduce your headaches with this engine from here on out.

[Learning]

Is it considered a big job to replace all the hoses including the small ones underneath? The last time I had all the hoses replaced was about 7 years ago and I don't really remember if it was a big job or not. Actually, how often should we replace all the hoses?

[Reap3r]

Is it considered a big job to replace all the hoses including the small ones underneath? The last time I replaced all the hoses was about 7 years ago and I don't really remember if it was a big job or not. Actually, how often should we replace all the hoses?

You can basically remove all of the hoses underneath if you wanted to. There are a few threads around that give you ideas on how to clean up the mess under the intake. Out of those hoses under there my car is only left with the one that goes to the radiator and the vacuum line for the fuel pressure reg. Allthough that will be changed for me soon once I get a new piece fabricated up to incorporate a heater again.

[Martin C.]

Leaks are bad, certainly as you get older ;). Good luck with the haunting!!!