N52 Slight Misfire/No Codes-Smooth running values off

[bmwpriest]

Hello everyone,

this is my first post on the board. I must say that bimmerforums is a lot more resourceful than what we get in Germany.

So, to my issue. I will try to describe the whole story with my E63 630i with the N52 with 220.000 Km (140.000 Mi) to make sense.

Bought it a month and a half ago after sitting for some time (1-3 months, not really sure). Ran well, except for heavy lifter tap. To this day it has power, fuel mileage OK, WOT fine, runs good throughout the rev range, only the idle bothers me a bit.

It does hold revs at about 650, but I can feel some vibration, rather similar to a 6-cyl BMW diesel. You can feel it in the steering wheel, but not like the whole car is shaking. I drove older beemers and my idle is nowhere as smooth as in, say, an E46 323i. Running A/C seems to make it just a bit more noticeable.

In Addition, I´ve encountered some rough running/hard hot start Problems occasionally, but they seem to have gone away. There was almost a full tank of fuel in the car when I bought it, so I figured I´d just drive it a while, pour some Liqui Moly injector cleaner and it does seem These are gone for now-I´ve covered some 3500 miles since the purchase though.

Diagnosis: I got a C110+ BMW scanner, and my car used to have bank 1 and 2 fuel mixture, vanos intake, and valvetronic sluggish codes when I bought it. Cleared codes, cleaned Vanos Solenoids, put them back in, no codes. I check every once in a while and got a Vanos Intake Code some 3 weeks ago. Cleared and it hasn´t returned. Car is being driven daily.

Went to check smooth running values, cyl. 5 way thrown off. Goes to extreme - then + and so on. Switched plug and coil with another cylinder, No. 5 spiking again.

That leads me to either injector No.5 or an air leak Close to the head/ No. 5 runner. Worst-case Scenario would be valve damage, which I hope is not the case. As previously mentioned, I have a loud ticking that doesn´t ever stop and it´s coming presumably from cyl. 3 or 4. Could also be 5, no idea...


So before I open the VCG to look for physical damage on HVA´s and rocker arms, I´d like to get second opinions on the matter. My guess is that id doesn´t make sense to check for failed sensors(MAF etc.) because the smooth running test Shows No. 5 as running irregularly, therefore localising the misfire to just one cylinder.


I am no professional, but do have a Basic understanding of how an engine functions. Please, do not take my assumptions as correct, and look at the Problem from a professional standpoint. I hope someone has the nerves and the interest to help me.

Regards,

Filip

[MarcoZandrini]

I’d definitely have the intakes smoke tested. A vacuum leak’s impact decreases as the revs increase. Also, how is the car driven? Do you drive it on the Autobahn? What exactly is the code and it’s definition?

[bmwpriest]

Ok, I’ll give the smoke test a try.

The car is driven 50/50 Autobahn and city, but not at high RPM’s. I’m avoiding that since I got a coolant leak from the top radiator hose, which I’m about to adress. Then I’ll just run its ass off and see if the engine runs better or the valve lifter tap reduces. Also, I’ve used 5W-40 Magnatec on a recent oil change.

There are no codes currently, nor a CEL.

[MarcoZandrini]

That sounds like the plan. Almost all BMW engines love to rev. It’s sort of like allowing the BMW goddesses to sing!!

I’d perform a compression test on that bank of cylinders. Also, try a leak down test. You may have an issue with the rings in that cylinder or a valve not seating properly.

Here in the USA we have gas that’s called “top tier gas” (www.toptiergas.com). I buy only Shell premium or Chevron premium where it’s available. I replaced the injector orings in my old E46. It had 120k miles on the clock. The business end of each injector was pristine!! I don’t know if there’s something similar in Germany. I’d do some research as to which gas does the best job of keeping the injectors and intake valves clean.

[bmwpriest]

Well, at least I tried. Since I got the coolant hose fixed about 10 days ago, I´ve been driving my car hard at times. The engine runs awesome, it pulls hard and without hesitation, but my idle is still the same. This morning I left the car outside and it was about 5 degrees C outside, and upon Startup the idle was rough for a few seconds. So definetely more pronounced when cold. Driving hard didn´t settle my lifter noise either.

I hope I´ll catch some time next week to do a smoke test. I am also planning to download INPA to my Laptop and see what´s up with the injectors.

What I thought would be just small issues that can be quickly fixed proved to be continuous hurdles. I changed my Control and thrust arms + tie rods and I still have a Vibration when braking at somewhat higher Speeds. It´s the Discs probably. I already tried re-bedding and reduced the Vibration by doing so, but it´s still very noticeable. And the Brakes are only 6.000 km´s old!

Plus, I got some condensation in my driver´s side headlight after running it hard. This car does indeed take a lot of my time and Focus.

[JoJo30mil]

Just a thought im not a professional mechanic but I would recommend checking the disa valve and double check the spark plugs to see if they have oil build up on them.

[bmwpriest]

So how do I check DISA? I am about to install INPA so I can perhaps use that, no?
Anyways, I think I´ve found the suspect. Ever since I bought the car, when I fill up more than 3/4, the car won´t start for some time. Eventually, after a couple starts, it fires up but you have to almost floor it while starting. It must be the purge valve!

I´m going to replace and come back with results.

[MarcoZandrini]

Get inpa up and running.

[zapolini]

Hi. Again - first post - same issue in an E90 325i N52. Not trying to hijack the thread, just hopefully contributing some additional information. Information gathered from a C110 scanner.

Cylinder 5 smooth running values all over the place. LTFT bank 1 around 10%, Bank 2 around 20% - both fall to around zero at around 2500 rpm. Idle is very slightly lumpy, and hesitant at part throttle/low rpm. Serious lack of torque at low engine speeds, but once above 3000rpm, seems much better. All 6 ignition coils are fairly new and Bosch. swapping number 5 spark plug with another didn't affect the smooth running values. Both Vanos solenoids are new and working fine. MAF sensor seems to be reading correctly.

I have a feeling there is an injector issue, as well as an air leak.

OP - are you any further on with your problem?

I was going to swap number 5 and number 2 injectors - see if the smooth running issue moves, and see if the higher LTFT moves from bank 2 to bank 1. Does this seem like a reasonable move in order to diagnose things.