Weird Problem - E46 BMW 318i N42

Hi guys,

Been having this weird problem with my car from last week.

Basically, its an idling problem and power loss.

Cold start up its fine, once the engine gets up to temperature, and I switch the car off and start again, it starts fine, but the idle drops to just below 500rpm, then the car catches itself and idles normal (700rpm), but the needle fluctuates ever so lightly.

Then power has been down significantly. In 5th gear it feels as if the 'vano's (I assume it has) is not adjusting at all. But in the lower gears (1,2,3) I can feel it, but power is down throughout.

I have taken it for a diagnostic and everything seems fine, all sensors indicate everythings operating within range.

I have tried checking for vacuum leaks, but only removed the airbox, seemed fine. Tried unplugging the MAF, but the idle just goes crazy then, starts jumping up and down, but higher. Also while idling, unscrewed the oil cap and idle becomes 'lumpy'.

Have read that it could be the crank case vent valve, but would that cause a significant power loss?

Inspected the coils also, seemed fine.

This forum rocks BTW, very imformative

Edit to add:
Changed the Voltage regulator thingy on the alty and Crankshaft sensor 2 weeks ago (genuine part) and car ran fine. Problem seemed to start after I gave a Kombi a boost - followed all the correct procedures. So not sure what to do now!

Loss of power between 1000 and 2000, almost so that you stall the car ?

Have your VVT motor checked...

But otherwise, MAF, VANOS, CCV, VVT, Cam Sensors, Crank Sensor, O2 sensors... any of the above

Thanks for the reply boet.

Yebo, loss of power also.

Ouch, VVT motor sounds expensive. Would a diagnostic not pick it up?

Anything that I could check myself?

So much hey. Dam these N42 (N46 actually on mine) engines, such brilliant engines but so troublesome!

My best advice would be to go to someone who can get the codes read.

No sure where youre from.

Also, that N42 doesnt have Vanos. It has a Valvetronic which controls the "Extra" cam. The Valvetronic system consists of a motor and some sensors. If this system starts to fail you would experience symptoms similar to what youre having right now.

Its kind of tough to know exactly what the problem is but Ive personally experienced the Valveltronic System Failure, with similar symptoms.

Fear not. if it is the Valvetronic motor, it is not that expensive. Mine cost me R1700 to replace, with labour. If you are doing this, i would advise an De-sludge and an oil change.

P.S. even if it is not this problem, i suggest a De-Sludge / oil flush and oil change as preventive maintenance.


Hope this helped. Depending on where you are, there may be members on this forum who can assist you in reading the codes. If not, find a reputable mechanic to get the codes read.

Thanks for the advice Xmax, much appreciated buddy.

I'm from Durbs, North Coast.

I have had it in for a diagnostic with the reader plugged in, etc, and no fault codes came up whatsoever.

Ok yes I remember reading valvetronic - thanks for clearing that up.

R1700 is not bad at all.

I will do the desludge also, thanks man.

Anyone from Durbs here who could assist?

You know where your VVT motor is right ?

Unplug the cable, it should have 2 pins on it, using a multimeter, check to see if you have ANY resistance between either of the two poles of the motor, and ground (the outer casing)

There should be infinate resistance (same as trying to measure electrical current through plastic, ie not going to happen) between the two poles of the motor and the casing of the motor (ground)

If you have ANYTHING, motor went poof, and you then have to replace at agents. Tappid cover off, change out motor, and then you need to have BMW DIS or ISIS to set limits on the motor again.

No I am not clever at all, this was exactly what was wrong with mine and how we found the problem, this was WerriesM5's brilliant work....

Other then that, start plugging out sensors, see if that makes a differance. Could be O2 sensors, could be coils and plugs as well..

Edit :

Incorrect assumption. The N42 motor has both Valvetronic (VVT) AND vanos......

@ZALE - My apology bout the Vanos issue.

@Trigger. Depends on how far north you are.

I have a buddy who works in Effingham. He is very good with BMW's and has all the correct equipment.

His name is Rupesh and owns RM Autotech.0832892744. Tell him that you were referred by Veru, Rahuls Cuz.

Give him a call. he's quite accomodating.


Also, as was said earlier, it can be a few different things. So if you are a little car savvy, then try the test that ZALE suggests. if not, get it taken to someone who knows what to look for. not some mechanic whos worked with bmws. Get someone who specialises in BMW.

hope this Helps.

ZALE - once again, I apologise if i appear to have mislead this member regarding the vanos issue. Thanks for clearing it up.

XMAX, dont stress dude, I was also confsckulated, but I have done a lot of reading on the N42 the last few days...

I also did not know until this weekend, so all is well

Guys, just make sure that they set the limits on the valvetronic motor in front of you. Its a tricky piece of software to have. You will hear the motor go ape..

Hey guys, thanks again for the replies, info and assistance.

Xmax, I took it to your contact straight after work yesterday, he ran a diagnostic and once again - no error codes. He listened to the engine for a bit and said it could be the Crankcase Vent Valve (first he said valve - got worried that it dropped a valve:shocked

So hoping its that and not some electronic fault! I do believe that I need to change the VVT stuff though because of the 1000-2000rpm hesitation. Need to save up!

But there goes my M-Tek front bumper for this fault:banghead:

Interesting info - the Toyota RSi/RXi 20v's also have VVT and when the gear goes, performance doesnt drop, but the car sounds like a diesel.........part is R2200.....so R1700 for changing the VVT stuff on this motor is not bad at all:thumbsup:

What did he quote you for the Crank case breather ?

R600 for the part and R600 labour. He usually charges R250/hr but discounted it to R600 for 3 hours work.

But obviously I'm not convinced that is the fault until its sorted.

Can I get a pirate part?

Cool Trigger.

My advice is to never use any pirate components on your car.

Also, if youre not picking up an error code, then chances are that there isnt anything wrong with the Valvetronic system.

R250 / hour is actually cheap, and hes offering you a R150 discount. nice.

This sort of problem is not the easiest, and in my case the Valvetronic system was indicating a fault code.

i know the guys is my contact. but if youre not happy with his diagnosis, i say get a second, or even third opinion and quote. if they all say the same thing, then get it changed as a precautionary measure. that way even if its not that, you prevent a future failure of the breather (which is a problem which does occur from time to time on BMW's).

Hop this helped.

Actually lets discuss pirate parts for a second.

pin type plug in coil from BMW - R660 excl (which is actually Bosch) . Original Bosch part, R350 each. Fong Kong Coil/waterpump combo. R9.43

Another classic case, BMW wants R92 million for each little gasket. A upper timing cover gasket can easily go for R700. Yet you can buy a full Victor Reinz gasket set for a V8 motor for like R3,000, and then you get everything. By the way, guess who makes gaskets for BMW...

Many examples of this. ZF makes gearboxes, BMW approved gearbox part vs ZF original part. Half price.

Same discussion witht he MAF, made by Bosch, but R1800 vs 5k for the SAME thing from the agents.

I actually baught a expansion tank from my local spares shop over the weekend, its exactly the same part as BMW, so much so that you can see where the BMW logo was on it, but it was scratched off due to BMW getting nasty about stuff like this. Part R650. same part at the agents, got a quote that morning R1990.....

So....

However, service parts, filters and stuff. I proved it again this weekend, OEM is cheaper then your local spares guy, or at least the same. I would rather have OEM.

Had a chat with Mike from BMW The Glen, and I showed him what I discovered, and I said we would all love to buy OEM, and if there was a 10% premium or so for OEM stuff, most guys (i would) pay it, but 100% ???..??

Zale - Good point.

however none of those parts are pirate parts, as they are not cheap ripoffs of other parts. They are low cost , high quality replacements.

Sure the stealers rip us off big time on almost all components. but i dont believe in buying some Chinse ripoff just cos its cheaper.

Sure, if you can get a quality replacement component cheaper, then by all means go ahead, but it has to be of at least a good quality standard.

Thanks Xmax, I agree buddy, I dont usually fit pirate stuff on my car as I do like 100km a day so wouldnt like to break down, but just out of interest.

Yeah I read about the breather giving up anyways so will get it changed nontheless after a proper diagnosis when the intake is off.

Your guy is good, saw him working on an E-Class supercharged and one million other vehicles, even an E46 M3 parked there for repairs - so his labour is definitely worth it. I had it at another local BMW Mech in my area and he told me the same thing so I'm pretty sure it might 100% be that specific part.
Xmax, thanks a million though buddy, if you didnt give me his number, would still be worried.

@ Zale, you make very good sense bro. I bought a brand new radiator for my old E46 for R750 incl. the cap compared to BMW's ridiculous pricetag, even if it lasted only 3 years, it was worth it, but still running fine with the new owner.

Guess for intricate long term parts you have to go genuine OEM, otherwise stuff like coils/maf's, etc where they are known to fail (even OEM), then its fine to go pirate.

@Trigger, youre welcome.

Yes Rupesh has lots and lots of cars. He is very good at what he does, else i would not have refferred you to him.

That M3 is damned fast. Using Heads by Mopar and running Nitrous. That car destroyed its SMG Gearbox and Diff. Had to have it converted to Manual.


Also if you are looking at doing bodywork and other mechanical work, I have another buddy of mine who is quite good and both. He is Near Pinetown, so if you or anyone else is interested, his name is Rahul Isaacs. 083 784 5025. Tell him Veru Sent u.

Shot bru.

I can see that bro and he doesnt advertise, just word of mouth - yet he is busier than perhaps a dealershipimp:

Yoh that is fast. Since its damaged and stuff, he should just rather swap that M3 for my car
(Next car is hopefully an E46 M3 for evryday use)

Cool man. Nice to meet up with good BMW contacts as there is certainly not an abundance of aftermarket services in regards to BMW's here in local Durbs.

Thanks again man.

Hi Guys
Sorry, new man here on the block, and also new E46 318I owner...
Just reading the above bits, with specific reference to the radiator expansion chamber problems, which I believe is an E46 weakness- am I correct in assuming that the hose that connects to the chamber (at the chamber) has the clamps shrunk on? Mine seems to be leaking at the clamp. Could one not cut it off and fit a jubilee type clip? Doesn't seem to be the expansion chamber itself that's leaking. Any help would be appreciated...

XMAX said:

Cool Trigger.

My advice is to never use any pirate components on your car.

Also, if youre not picking up an error code, then chances are that there isnt anything wrong with the Valvetronic system.

R250 / hour is actually cheap, and hes offering you a R150 discount. nice.

This sort of problem is not the easiest, and in my case the Valvetronic system was indicating a fault code.

i know the guys is my contact. but if youre not happy with his diagnosis, i say get a second, or even third opinion and quote. if they all say the same thing, then get it changed as a precautionary measure. that way even if its not that, you prevent a future failure of the breather (which is a problem which does occur from time to time on BMW's).

Hop this helped.

Click to expand...

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Hi Guy's

I have a 318i facelift with the following symptoms:

1.) Rough idle on start up
2.) Engine noise on start up
3.) Overfueling smell from engine
4.) Loss of power periodicaly between 700rpm - 2000 rpm

The weird part is that I can start the car and drive the entire day but if I switch it off and try to start it lets say 15 minutes later, it doesn't start but if I unplug the air mass meter sensor or let the engine cool for about 30 minutes, the car starts!

Ran a dignostics test and picked up the fault of 'valvetronic actuator' however no EML light is on an when ran diagnostics for the second time, the fault code didnt even pick up!

It seems as though when the valvetroic motor heats up the car doesnt start but when cools down, then it starts.

Also, think by unplugging the air mass meter, the engine goes into limp mode and starts??

Any ideas guys? Im totally out if ideas now

Wolverine said:

XMAX said:

Cool Trigger.

My advice is to never use any pirate components on your car.

Also, if youre not picking up an error code, then chances are that there isnt anything wrong with the Valvetronic system.

R250 / hour is actually cheap, and hes offering you a R150 discount. nice.

This sort of problem is not the easiest, and in my case the Valvetronic system was indicating a fault code.

i know the guys is my contact. but if youre not happy with his diagnosis, i say get a second, or even third opinion and quote. if they all say the same thing, then get it changed as a precautionary measure. that way even if its not that, you prevent a future failure of the breather (which is a problem which does occur from time to time on BMW's).

Hop this helped.

Click to expand...

---

Hi Guy's

I have a 318i facelift with the following symptoms:

1.) Rough idle on start up
2.) Engine noise on start up
3.) Overfueling smell from engine
4.) Loss of power periodicaly between 700rpm - 2000 rpm

The weird part is that I can start the car and drive the entire day but if I switch it off and try to start it lets say 15 minutes later, it doesn't start but if I unplug the air mass meter sensor or let the engine cool for about 30 minutes, the car starts!

Ran a dignostics test and picked up the fault of 'valvetronic actuator' however no EML light is on an when ran diagnostics for the second time, the fault code didnt even pick up!

It seems as though when the valvetroic motor heats up the car doesnt start but when cools down, then it starts.

Also, think by unplugging the air mass meter, the engine goes into limp mode and starts??

Any ideas guys? Im totally out if ideas now

Click to expand...

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Dude! It sounds like we are in the same boat hey!
I'm sitting with the same symptoms, just a bit more aggrevated. But also seems to be way worse when warmed up or when its hot outside.
See here: http://www.bmwfanatics.co.za/showthread.php?tid=26713

Check your vvt motor as mentioned by ZL on the first page of this thread. I checked mine and it seems to have blown. Gonna get it replaced soon. I really hope thats gonna be the end of my troubles.

Leonard might be able to shed some more light on this though.:thumbs: