My E46 weekend - N42

SO as most of you know, a few months ago I purchased a lovely little E46 318 for the wife, high miledge (170k on the clock) but in really decent condition cosmetically, and even mechanically.

The car had an annoying issue whereby at 500 to 2000 rpm the car would loose power, almost to the point where it wants to starve itself.

This is very dangerous in intersections, as you have to rev over 2000 rpm before you apply load, else the car bogs down and dies in the middle of the intersection.

Out of principle I did a service, changed plugs and 4 coils, did not fix the issue.

Werries helped me swap out a VVT motor.

Swapped out a MAF with gopher, which I must still return, my car the same issue, gopher fine so that rules out MAF.

So this weekend I borrowed another N42 318 compact from my dealer so that I can start changing out sensors one by one.

A small rant, HOW THE MOTHER F do you rape a car like that. This car looks very very neat on the outside, however... interior is half loose, cluster is swapped out of an auto, half the clips and brackets in the engine bay is just not there.

The DSC is complaining that the DSC pump does not match the vehicle, causing a perm traction control light, so then you just remove the lamp from the cluster, no problme.

The amp, OMG, 1.5mm cross section house lighiting wiire is used for both power and ground, with positive being stuck into the battery terminal with 4 strands of wire. I shit you not, I almost lost it, and its not even my car....

Anyway, after removing that amp out of prinicple, I set to work.

First things first is I changed out the VVT sensor, which involved taking off the tappet cover, as I was convinced that was the issue.

That did not quite work, so the next was cam sensors, those did not work, next was VANOS solenoids, those did not work. Same issue, no change in the car.

Then I gave up for the day, and went to golf reef city with my wife and daughter, and screamed like a little girl on the rides.

This evening WerriesM5 popped past, and we swapped out VVT controller, still same issue.

Then we swapped out throttle bodies, and while doing this, we also discovered a small leak on the air filter housing. Took the car for a test drive, and it seems fine now, we will check it the next couple of days, and if the issue persists, it can ONLY be crank sensor, as I have swapped out the entire VVT system.

Crank sensor however requires taking off manifold.

Note the N42 has VVT, Vanos, MAF, MAP and a dumb computer system that does not know how to manage all of this properly if a sensor is out of spec.

I believe according to Werries that the N46 is bolt for bolt the same as the N42 except for the fact that it has much more refined electronics to pick up when a sensor is out of spec.

Anyway, thanks again to Werries, you ROCK dude, and I am in awe of your knowledge, and as for my wifes car.... we can only hope its fixed now.

Anyway, thats been my weekend, what did you folks get up to ...

sorry to hear about all the bad luck , i can only hope you had a heater in the garage, Throttle body seems a very strange cause to the problem , glad it sorted though , and hope the problem stays away. :thumb:

I hope so too, I almost felt like selling the car, and stal said if I have further issues with it, he will pay me back what I paid for it, but I dont want too, its a neat little car.

As for the TB being the issue, remember that this is drive by wire, and the throttle plate is actually driven by an actuator, its fully electric.

It also has two pots inside to determine its position, and if one of them goes faulty. you can get all kinds of unexplained crap....

I look at that BMW, and I look at my bird, and its a frikken world of differance, it really is...

o yes the drive by wire :banghead: that explains alot..

zl

a week ago i cleaned my TB, i noticed that the butterfly of the TB was at a slight angle, i.e. very-very slightly open. is that normal or is it a sign that its starting to fail?(have the same issue with my e46 318)

i know this will be unhelpful and quite annoying... but...

6cyl FTW!!! (least until mine gives me problems)

The N42 is a lovely motor, lots of gremlins when it acts the fool like in your case here Z(had my fair share too) but does produce alot of bang for your buck, i dont know why people hate them so much,

My daily Drive is a 318ti, love it to bits i decided i needed more power and mech advised me to rather just buy a 6cyl and not tamper with the N42 so i said fine, i got myself into a 325ti and to be honest on the urban commute they actually feel quite similar(putting on bullet proof vest now) its just when you really flog the 325 you feel the extra power but city driving i wasn't too impressed but the exhaust note of a 6pot always puts a smile on my dial.

Well, the actuator does not really fail I think, if it did, you would KNOW about it.

What goes is the two pots, and then the ECU gets wierd readings....

I figured that if i cant solve this, I am going to do an N46 conversion on the car, which involves ECU and wiring harness....

But Chucky, I am with you, they are lovely little cars.

As for the 6 pot, you have the same electronic bitties, things that can go wrong, what lets down the N42 is its electronics, not the engine.

Every machine has its niggles - hope you get it all working 100%! Nothing more satisfying that solving a stubborn problem! My Wife's E46 also has various issues which I am slowly working through, but whenever I have the slightest doubt I look at some of the other "newer" and supposedly more economical cars in our area and quickly remember why I bought this car!!!

Z if you can do a N42 to N46 conversion on your wifes car much respect.
in my mind this is a big and expensive job correct me if im wrong.
I also wonder if the stealership can reprogram the N42 ECU up to N46 spec, or is it is a whole new ECU
our old 120i had the N46 motor and on face value The N42 and N46 Motors look identical, so it has to be software.

Chucky,

Thats exactly the thing, you cannot remap the N42 to N46 ecu simply because the N42 DME does not have VVT built in.

On the N42, VVT was an afterthought by BMW, this is evidenced by the VVT controller sittin in the bonnet top right hand side, unprotected.

On the N46, they integrated the VVT to be part of the DME, and they actually do signal plausability reporting as well, which makes it far more diagnosible.

As for the costs, well thats going to depend.

You either need an undoced N46 DME, then its quite easy, or you need a used N46 DME with EWS, and of course the N46 wiring harness...

Man I wish I had the time to stuff around with this stuf..... Its actually really fun.

Im about to buy an oscilliscope so that I can start doing signal/sensor diagnostics. I dont believe in this replace stuff till you find the right part thats not working bull.....

True that,
electronic gremlins are a love hate thing and you do need the right tool for the job other wise you will be wasting your time.

and then there are just days when electronics screw you over, once my VVT motor gave a voltage error on diagnostics resulting in the EML light coming on and the car would randomly go into and out of limp mode while driving, that was not sheer driving pleasure that was sheer k@k driving pleasure any way had the relay tested, checked for bent pins on the VVT connector lead which stopped the car going into limp mode but the EML light stayed on, next checked if the relay was faulty and nothing helped wanted to sell the 318 at that stage, but after a nice prayer session and letting the car stand over night the next day everything was in order(and still is),

the EML light went off when i started the car, nothing changed the car just stood over night the next day she was fine... damn electronics LoL

Interesting, how long ago was that.

Remember that heat changes the charectaristics of electronic components, and that makes life so much harder.

BTW, learnt something interesting, unplug the VVT sensor, the valve lift is set to maximum. car still drives like crap, but it may give you that added advantage, does not even give an EML, thats how much of an afterthought VVT was on the N42.

N46 would poop in its pants I think...

This happened at the end of April/beginning of May this year so it wasn't that Cold yet.
lol i had enough of VVT fiddling for this year just now this thing acts the fool again

bottom line the N42 is a great engine in my opinion i think it won an award in 2002, also and the fact that they still use it(N42/N46 engine) in the in the e90 and e87 shows that it was ahead of its time way back when it came out.

Indeed.....

As I say, the N42 an E46 with a manual transmission makes for a really lovely ride,

Folks...

So two days of testing by my wife seems to indicate that the car is now sorted.

I am still not sure if it was the vacuum leak, the throttle body or any of the 92 other parts I had already swapped out, but I am now seriously happy with life.

Again, ta to WerriesM5, and to the poor abused 318ti for donating its bits, and ESPECIALLY to gopher whom I still owe a MAF too.. I'll be in touch

:thumbsup: glad to hear this

OK, so I never updated this, partly because I was too depressed..

Car was wonderful until that thursday where my wife got stuck in a shitload of traffic, and then it started again.

So this evening Werries popped past with a fresh crank sensor, dropped off the intake quickly, changed out the sensor. I cleared adaption, did not even bother taking the car for a test drive. My wife can do that.

What I am pleased to see is on the oil seal/casing around the crank sensor, you can see where it has physically lifted a bit, tiny but visible, meaning that the sensor is prob stuffed.

I have changed every single position sensor in that motor.... period, this has got to be it.

If its not... fsck it, we need to start looking at fuel pump and pressure...

But here is hoping, all logic says that this is an electrical problem...

Gremlins.... my e36 328i drivers door will sometimes lock and unlock with remote ,works all the time with the key . Wind is howling at 60 km/h and better to stay indoors :=):Rev counter overreads so want to get to sensor on front of motor - need to take radiator out to see !! will have to check if 325i one is same , can do swap . 325i with 410000 km starts first time every time just rusting away though !!!
Spending weekend behind laptop , chance to read a few magazines as well .

I remember I mentioned in your other post about an air leak, glad you got it sorted.