E46 Fanatics Forum banner
1 - 5 of 5 Posts

4 Posts
Discussion Starter · #1 ·
This is my first post, I am stumped by this car.
So original issues; car wouldn’t accelerate past 3000rpm, runs and drives under its own power, idles a little lumpy.

What I have done;
1. Scan the car;
-2B63 Crankshaft sensor, exhaust

-2A67 valvetronic,actuator motor:activation

-2F44 EWS preventing manipulation

-29CC Combustion misfires,several cylinders

-29CD Combustion misfires,cylinder 1

-29CF Combustion misfires,cylinder 3

-2A6B Valvetronic,power limitation

-2A63 Valvetronic,actuator motor:monitoring sluggish movement,direction of rotation

2. Notes
-The engine bay is very oily

-The valve cover was leaking

-The sump was leaking

-The solenoids at the front are also leaking

-I haven’t, as of right now, changed anything besides the spark plugs

2. Ruling things out
-Valve cover removed

-Timing checked -off by about two teeth maybe one - exhaust side as per DTCs

-Fuel pump fuse pulled

-Compression test prior to anything

Cyl 1: 10 bar

Cyl 2: 7 bar

Cyl 3: 9 bar

Cyl 4: 9.8 bar

-Oil is fairly old hasn’t been changed in a while

-Slight mayo but not a crazy amount (less than a teaspoon)

-Eccentric shaft sensor connection had oil inside - removed, cleaned, blown with compressed air - reinstalled

-With the valve cover off, I connected the valvetronic motor, and not the eccentric shaft sensor

-Tried to use the scan tool to realign the valvetronic to see movement, no movement as expected

-Connected the eccentric shaft sensor, aligned, movement as expected

-Checked the valvetronic motor using a multimeter - doesn’t short out (ohms wise)

-Then in the interest of not throwing money at the car, retimed it using the current timing chain, (working on cars is my therapeutic escape - time is plentiful)

-Pin in the flywheel, camshaft locks on, vanos bolts loosened, tensioner removes, impulse sending gears locked in place, pre tensioning tool installed, everything tightened up, tensioner reinstalled, timing tools removed, engine rotated twice, checked timing again, all perfect

-using the same parts the valve cover was put back together, the coil packs have been numbered

-started the car similar issues

4. After retiming the engine scan
-29CC Combustion misfires,several cylinders

-29CE Combustion misfires,cylinder 2

-29CF Combustion misfires,cylinder 3

-Car still wouldn’t rev past 3000rpm

-After throttling several times it wouldn’t really rev past 2000rpm

-Fuel pump fuse pulled

-Compression test post-timing

Cyl 1: 10.5 bar

Cyl 2: 11 bar

Cyl 3: 11 bar

Cyl 4: 10 bar

-Changed the spark plugs with new

-Similar issues - cyl2/3 misfires

-Swapped coil packs over cyl 2 to cyl 1 and cyl 3 to cyl 4

-Same issues

-I briefly watched a video on how the o2 sensor graphs work pre and post cat and deemed the catalyst to not be blocked, I also compared (unconventionally) the exhaust air pressure on my hand from this 318ci to another working 318ci - no difference. I saw the pre cat o2 sensor fluctuating and the post remaining steady

-The intake air temperature sensor was showing -40c however that may be the MAF sensor unplugged (I am assuming it’s built into the MAF on the N46)

-The car idles okay, sounds lumpy on max rpm whether that’s 2000rpm or 3000rpm, after the new sparks it briefly got to 3500rpm

-If I try to wide open throttle it the car sounds horrible at its limited RPM and dies

-Throttle body hasn’t been touched? Diagnostics did show it opening 100%, the accelerator pedal was also fine too

-Vanos solenoids untouched too

-MAF sensor was disconnected/connected with no avail to higher revs

-Battery removed for 30 mins again to no avail

-Codes reset etc, held down the accelerator with ignition on for 30 seconds then held the brake and started the car, still no improvement

-below 2000rpm it revs fine, it does struggle to move under its own power, this makes me wonder whether it even is a leaking injector

-Valvetronic lifts seem okay according to the computer 0-7mm maybe more

5. My verdict
-It’s not the spark plugs

-It’s not the coil packs

-I haven’t checked the engine harness

-I’ve seen the valvetronic move and realign and the codes also didn’t come back, I also used the computer to realign this after each tinkering session

-After revving the engine because I didn’t seal/replace the valve cover gasket quit a bit of smoke comes out the rear side of the engine closest to the driver position (RHD vehicle)

-The last point could also be the vacuum pump seals leaking

-Not much variation in the DTCs, but I’ll happily take anyone’s suggestions on trail of thought/diagnosis

-I might just pull the engine after another project is finished because all the seals do require attention and then it would be easier but if I don’t have to I’d rather continue tinkering haha

-I have a smoke leak detector that I’ll try use in the near future also

6. What do we think? All the gear but no idea hahaha
-Massive vacuum leak?

-Stuck open injector?

-Throttle body sticking?

-Valvetronic issue somewhere?

-Vanos solenoids?

-Oil change? - with engine flush?

Any insight appreciated, if it isn’t clear I’m only a hobbyist and not a mechanic but I know a few things, and I don’t know a lot of things Hahahaha

Glad to be here, thanks in advance!


Premium Member
E30M3 Race F10 535 R1150Rt M Coupe
11,388 Posts
If such a car were in my shop (we didn't get that engine, but is very similar to other 6 cyl. "N" engines) I would have to do a LOT of testing to verify what is working correctly and what isn't.

Just a WAG (wild ass guess) would be something Valvetronic related?

Sent you information in a PM.

4 Posts
Discussion Starter · #3 ·
I have since read through the information and learnt a lot(!).

So the N46 B20 does have a DISA valve... cool

Anyway, there’s a guy called jfoj somewhere on the forums and I have read a lot of his responses to similar issues. I took his advice and ordered a VDO fuel pump, I arrived at a fuel pump conclusion after doing various tests/checks.

Here’s what I have done:

  • Cleaned the front face of the engine (with brake cleaner - bad idea?!)
  • Removed the vanos solenoids and bench tested them
  • Smoke leak test (vacuum leaks)
  • I checked all fuses with a multimeter and checked all missing fuses are supposed to remain missing
  • Fuel rail pressure test
  • Visual inspection of the fuel pump
  • Scanned for codes and deleted codes multiple times (2B63 - camshaft, exhaust sensor), nothing else whilst idling; however when I try rev the engine I still get a misfire cylinder 2/3 - which doesn’t move
  • I also noted the valvetronic status to be in limp home mode active


  • Vanos solenoids don’t have an o-ring, but poor workmanship gasket sealer
  • Seemed to be oil in the Vanos connector which I cleaned with brake cleaner
  • I assume brake cleaner to be okay as it evaporates fairly quickly whilst dissolving particulates - please note the battery was disconnected and I only plugged everything back together after about an hour
  • Whilst the Vanos sensor was out I used my finger to find any o ring but obviously previous person used gasket maker
  • I felt the oil during the above and it felt slightly thick
  • Practically no vacuum leak except very slight seepage through the eccentric shaft sensor
  • Fuel rail pressure test: after serious concern about the accuracy of my fuel pressure test gauge I removed it’s shredder valves and confirmed it to be working on a old tyre (which won’t be out on a car)
  • I saw a post somewhere saying 50PSI is what it should be when the ignition is turned on (key in position 2, engine off)
  • Mine didn’t move with the above
  • With the engine on during idle, I saw the gauge flutter between 45-50PSI
  • On acceleration (but around 2000rpm - i.e. not maxed out at the cars limit 3k/rpm) the gauge stayed around 49PSI
  • The post I read said it should not drop below 43.5PSI with the engine off after 20 mins
  • When I turn the engine off it does drop instantly to around 44PSI, stays there for a while around 20 mins
  • I also read it shouldn’t drop a certain amount in an hour - and I’m pretty sure I left the car for about 35 mins and read it and it was lower than the threshold which I read - sorry paraphrasing, I’ll link to the articles I read in another post but jfoj (what a guy) was definitely posting in those
  • The above led me to check the fuel pump, it seems factory, one of jfojs comments said all E46’s by this time should have a replacement fuel pump and he’s advised people to buy Siemens/VDO and change the fuel filter a few weeks later
  • I read something along the lines of a failing check valve
  • Having said this I also read many horror stories (my opinion) where people have said to throw parts at the car and it didn’t resolve anything (however good to have these parts anyway) and it ended up being Case 1: a MAF sensor (however my car runs like crap without the MAF anyway and known good-ish 318s I’ve seen run good with reduced torque with MAF disconnected) and Case 2: burnt wires by the lambda sensors

Anyway me being me, unprofessional and always opting for educated guesses, out comes the parts canon:

I have on order:

  • VDO fuel pump
  • Mann fuel filter (I think with regulator built in - has a black sleeve in the middle)
  • Valve cover gasket (with o rings for the spark plug tubes and eccentric shaft seal) - (Doctor.Motor brand)
  • Crank case gasket set (includes lots of o rings I have no idea about - it’s a BGA brand) - for the sump gasket
  • 4 new ignition coil packs (Bosch)
  • 1 Febi camshaft sensor (I should have changed both but I didn’t think it through when ordering)
  • Oil - Castrol 0w-30 (some will frown, I personally don’t mind as its low SAPs and the gold bottle FST edge long life fully synthetic; long life but on my other cars I change it within 13 months and I barely touch 5000 miles/year)
  • Oil filter/Air filter/Sump bolt/washer

I need to source:

  • Vacuum pump seals (dealer?)
  • Vanos Solenoid seals
  • I read jfoj saying 7 clamps for the fuel filter?!
  • I also think someone said somewhere the fuel pump clamp is a special type of hose clamp which doesn’t damage the rubber line, so I need to find that
Order notes:

  • I have a bottle of STP engine flush which I’ll use also

Things I have yet to check (partly because I think I have conclusive evidence to throw parts at the car)

  • Full battery alternator charging current test
  • Injector spray test: Safely manually activate injector
  • Fuel pressure regulator vacuum hose: Visual inspection for damage/leaks
  • Run engine without upstream sensors to create exhaust leak eliminating blocked cat (unsure how wise this is)
  • DISA valve actuation bench test
  • Idle control valve - shake test
  • Throttle body clean

4 Posts
Discussion Starter · #4 ·
As mentioned (not everything I read)

Case 1:

VDO: (however mentioned numerous times everywhere)

Fuel pressure: (read entire thread)
Fuel pressure test done

Probably good to read if you’re here anyway:
Save yourself up to $200 and some headaches - Electric Fuel Pump PM | E46 Fanatics Forum

Am I allowed to post links to another forum?! (Apologies in advance if not - feel free to edit it out)
04 325i won't rev past 4,000 rpm at all. | BimmerFest BMW Forum

Something I skim read:
oxygen sensor stuck in lean condition | Page 2 | E46 Fanatics Forum

Jfoj saying the vacuum line for the FPR is an atmospheric filtered vent line and has little affect on the drivability:

E46 Sputtering on acceleration
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.