[Zee32]

My n54 has treated me well. Yesterday while accelerating aggressively my car went into limp mode and the engine started vibrating very hard. I switched off the car and started again, the problem persisted. Every time I start the car the engine shakes vigorously and check the engine light is on. I havent drove the car since

I read the codes on JB4 from the dash and translated them into their chart names and here are the codes :

29D1 ***cylinder 5 misfire
29D2 misfire, cylinder 6
29D0 misfirings, cylinder 4
2C78 8 AfterCat 02 sensor signal, Bank 2 (this is probably because actuator is unplugged in the trunk to have both exhaust flaps open)
2D60 VANOS control fault **

What do you guys suspect the issue is? I'm thinking of changing all the ignition coils and spark plugs, but then again not entirely sure even if that's a first step.

[dpaul]

Almost certainly the crankshaft sensor. Other codes may just be downstream events to the sensor failure.

Pretty easy fix.

Edit: don't see why the exhaust flap actuator has anything to do with the post-cat error code. That fault code may be real. Also, 2D60 is a VANOS control fault. That could be real but is probably downstream of the crankshaft position sensor..

[Zee32]

Originally Posted by dpaul

Almost certainly the crankshaft sensor. Other codes may just be downstream events to the sensor failure.

Pretty easy fix.

Edit: don't see why the exhaust flap actuator has anything to do with the post-cat error code. That fault code may be real. Also, 2D60 is a VANOS control fault. That could be real but is probably downstream of the crankshaft position sensor..

Should I still try installing the ignition coil and spark plugs to check? Or would that be a waste of time?

[dpaul]

Originally Posted by zack32

Should I still try installing the ignition coil and spark plugs to check? Or would that be a waste of time?

Coils and plugs are wear items. You could replace them if it has been a while, if it will make you sleep better.. Personally, I replace things when they break, not before. There is no particular reason to think about plugs and coils at this time.

[Zee32]

Originally Posted by dpaul

Almost certainly the crankshaft sensor. Other codes may just be downstream events to the sensor failure.

Pretty easy fix.

Edit: don't see why the exhaust flap actuator has anything to do with the post-cat error code. That fault code may be real. Also, 2D60 is a VANOS control fault. That could be real but is probably downstream of the crankshaft position sensor..

I messed up. I read the code wrong using my dash, the first code wasn’t crankshaft sensor but was indeed a cylinder 5 misfire. So 4,5,6 cylinders misfired.
The mechanic has my car, he thinks catalytic converter is bad as there is a code for that too and needs to be replaced and the catalytic converter costs ~ $1500


Do you think it’s the catalytic converter? I asked him what if it’s the downstream o2 sensor, but he thinks it isn’t.

I was planning to sell my car in a few months and now this happens.

[dpaul]

Yes, downstream sensor would not cause this problem. And your mechanics thought is reasonable- a degraded/ plugged up cat could cause this problem. The sensor fault is on the same bank as the misfires so that fits too.

Just get a used cat on eBay. No need for new. It’s not a terribly difficult repair

[Zee32]

Originally Posted by dpaul

Yes, downstream sensor would not cause this problem. And your mechanics thought is reasonable- a degraded/ plugged up cat could cause this problem. The sensor fault is on the same bank as the misfires so that fits too.

Just get a used cat on eBay. No need for new. It’s not a terribly difficult repair

Hey needed your input one more time. The mechanic replaced the CAT and he told me after he started the car it started shaking again. He now thinks the "chip/computer" that controls the fuel pump is not working and is pumping excess fuel and he ordered a replacement part and will be installing it to see if that fixes the problem. Which chip is he talking about? And why wouldn't it show up on the codes if that was indeed the issue.

He said the CAT did smell of gas so prolly needed replacement. :/

[mweisdorfer]

Why didn't you just go catless or at least high flow cats vs replacing 1 cat??

[dpaul]

Originally Posted by zack32

Hey needed your input one more time. The mechanic replaced the CAT and he told me after he started the car it started shaking again. He now thinks the "chip/computer" that controls the fuel pump is not working and is pumping excess fuel and he ordered a replacement part and will be installing it to see if that fixes the problem. Which chip is he talking about? And why wouldn't it show up on the codes if that was indeed the issue.

He said the CAT did smell of gas so prolly needed replacement. :/

If there was a fuel pressure issue, you'd most likely have seen it reported by the DME. I'd find a different mechanic as soon as possible.

What are the current codes being reported?

Please be very careful about reading them the way you are doing. If you plan on keeping this car you might want to invest in some decent diagnostic tools - a code scanner that can read BMW-specific codes. Or just install the freely available BMW factory diagnostic software (BMW Standard Tools) on your laptop. All you'll need to buy is a $45 cable (bimmergeeks.com). I'd recommend, strongly, BMW standard tools. There is a learning curve but it can provide much more detailed diagnostic information than a typical scanner.

Since you've had a VANOS code, I'd use it to watch for any divergence between commanded and actual cam position in real time

[Red_Bean_Bun]

Focus on the Vanos control fault. Pull out the rest of the data from inpa.

[TheMidnightNarwhal]

Originally Posted by zack32

Hey needed your input one more time. The mechanic replaced the CAT and he told me after he started the car it started shaking again. He now thinks the "chip/computer" that controls the fuel pump is not working and is pumping excess fuel and he ordered a replacement part and will be installing it to see if that fixes the problem. Which chip is he talking about? And why wouldn't it show up on the codes if that was indeed the issue.

He said the CAT did smell of gas so prolly needed replacement. :/

Oh my god dude you have to stop bending over. You seem to say yes to everything your mechanic says. Is he a mechanic or a BMW/Euro indy shop. Replacing cat with a new one just for a O2 sensor code wtf?