[dp.]

Hello guys !
I've recently bought a 535i and after 2 weeks I've ran in an un-solveable problem.

Some history :
Previous owner told me he did a refresh on the engine about 10k kms ago :
crank and rod bearings , timing chain , 6x injectors , 3x ignition coils.

Car is overall in good condition,absolutely no modifications whatsoever.
So the first symptoms stared to appear almost immediately after I bought it.Idle was hesitant when cold,once it stalled right after startup.
Then suddenly the car started misfiring on low revs and went into limp mode.
Used ISTA to determine a multiple cylinder misfire.
Tested plugs and coils - they are fine.Even bought new NGK plugs,but made no difference.
Got the injectors out and sent them for a test - 2 of them were leaking.
Replaced and coded them.Absolutely no difference.
Still misfiring,just on a different cylinder.Tried moving coil and plug but this made little to no difference - misfires were detected on other cylinders.
I think the car is running rich overall.All plugs are black from just a couple of minutes of usage.Engine barely idles,and if I don't rev it soon after starting,throttle pedal does nothing (I think its just because the engine is fouled).
No smoke comes out from the exhaust,but I can smell the strong gasoline scent,which turns into a sulfuric smell after the engine starts getting warm.
I've also noticed that it's getting really hot in the engine bay for 2-3 minutes of working.I'm starting to think something is blocking my exhaust.

Other things I've checked/tested
Vanos solenoids
Valvetronic

Diagnostic tools wise I only have ISTA,so no datalogs.
Any advice on the matter is appreciated.

[ChiltiCoatl89]

Check your Catalytic Converter(s), sounds like it may be the culprit. Sounds like all the issues of it being clogged, please inspect carefully. There are several reasons as to why it can clog up, poor fuel quality, faulty injectors, faulty Oxygen sensor, misfiring, unburnt fuel, oil leaking into it, running lean, running too rich, ETC. I really hope this helps, I never like to hear about a bad 535i or any 5er and i enjoy to help my fellow BMW 5er owners! a lot of us are very knowledgeable so you can keep your mind at ease we will assist as best we can! This issue is not unsolvable, its just a little messy and was not addressed and overtime became a bigger issue covering more parts of your 535i. If you do end up removing the cat, please show pictures if possible or video!

[dp.]

Thanks for the input ! Always loved forum communities,it's a shame social media killed it.
I also don't like my car running worse than my clapped out E36.

As for this issue,I've managed to get the car running good now.Sent injectors to be tested in a different shop,and they've found 2 of them leaking.Replaced and coded them.Car runs now.I've also had a problem with a vanos solenoid,which I also replaced.

There is another problem I haven't solved though - car starts misfiring when it gets in normal working temp at idle and low rpm.I have no stored codes.Also it cranks REALLY slow when warm(like the engine is starting to seize),and sometimes dies right after I start it.Since there are no stored codes,I don't really know what to do,except check engine grounding.Maybe faulty ECU ? I've heard of a similar problem,caused by one.I've checked the charge pipe,which looks good,and also replaced its oring.
I also bought a replacement PCV,which I will be installing these days.

[ChiltiCoatl89]

Glad to hear your 5er is back in action! As for your current issue, I will definitely look into and researching it, I love trying to figure out problems and especially for a fellow 5 Series owner, as I get to learn more about our platform!

[ChiltiCoatl89]

Check your Fuel Pumps! for the long cranking sounds like one of the pumps is gone or is on the way out. Your Battery is good as well correct?

[dp.]

It's not long cranking,it's more like hard to crank.
Anyway,I think I've found the culprit for this and the bad idle,which I will open a new topic about,because it's transmission related (torque converter).