[autoAER]

Hi everyone,

I recently changed out all fuel injectors, coded them, changed all ignition coils, did valve cleaning, and changed out the spark plugs. After putting the car back together and starting it, I noticed the car makes a sound kind of like a bunch of marbles rattling around in a tin can. This sound only occurs around 1-1.5k rpms. Upon driving the car, I felt that boost was not coming on properly. The car would jerk when building boost, and when rpms got higher (>3,000) boost would kick in smoothly all the way to redline.

What gives? It's kind of a downer when you spend $2,000 on parts and the car still doesn't work properly. I'm not even sure where to start, theres no code thrown for engine related issues- only an intermittent code for the catalytic converter.

I appreciate any help or advice!!

the car is a 335i sedan N54

[techwhiz]

Check vacuum hoses.

[autoAER]

Originally Posted by techwhiz

Check vacuum hoses.

thank you for the response, which ones exactly? should I retrace my steps in removing the intake manifold?

thanks again

[meekz]

Following, I have a similar sound after lowering the car and I get a jerking/cutting out feeling at about 1500-2000 rpms.

[jwalker87]

Assuming it did nothing like this before the work you did, I would check all the electrical connections, and anything else, you disconnected as part of the recent work. You also gapped the spark plugs before installing?

[autoAER]

Originally Posted by jwalker87

Assuming it did nothing like this before the work you did, I would check all the electrical connections, and anything else, you disconnected as part of the recent work. You also gapped the spark plugs before installing?

I didn't gap the spark plugs; I was under the impression that the OEM plugs do not need to be gapped!

I'll definitely start retracing my steps from the intake manifold removal. If any of the electrical connections weren't connected, wouldn't the car throw a code for it? It's really strange that it's not throwing any codes...

[autoAER]

now I can feel the hesitation/jerky boost when on the highway... feels like it's down on power, its not smooth. I checked the vacuum lines of the wastegates by pulling them out and seeing if the noise changed and the rattling sound got louder and more pronounced. Does this point to a wastegate issue??

[bleicht]

I had a rattling sound while my car was still under warranty and the dealer ended up replacing the cats(s). I'm assuming the element broke up. I could hear it when rolling slow near walls/curbs with the windows down.

I don't recall a down on power problem but it would make sense if the cat is all broken up and restricting flow.

[autoAER]

Originally Posted by bleicht

I had a rattling sound while my car was still under warranty and the dealer ended up replacing the cats(s). I'm assuming the element broke up. I could hear it when rolling slow near walls/curbs with the windows down.

I don't recall a down on power problem but it would make sense if the cat is all broken up and restricting flow.

That would explain the intermittent catalytic converter flow code causing the service engine light, but was there any issues with the jerky boost engagement? Because the car pulls just fine when past 2,000 rpms, but when boost builds up around 1,000-1,500 rpms, its jerky and feels like the car is deficient on power. Also, I assumed when the catalytic converters are going bad, the car will send out a lot of white smoke through the exhaust.