E46 318ti Compact /Intermittent dangerous hesisitation

[andrewp2014]

Hello Everyone,
This is my first time posting on a forum as my last resort. Loved this car since the first time I ever drove it when it first came out. Being quite a DIY enthusiast, last year I purchased this E46 318ti – however, in the last 6 months, maintaining this lovely beast has become ridiculously expensive and has left a multitude of senior mechanics speechless.
Symptoms
- At operating temperature – Loss of power/Hesitation/Almost stall
- (seems like throttle body gets stuck/car is starving??)
I have had an intermittent hesitation issue with the car when pulling off from stand still – i.e. at a robot/interchange when pulling off – the car hesitates so badly as if it wants to stall / revs refuse to climb above say 1500 rpm for a few seconds say 0-10 seconds or anywhere in between no matter how hard I push the accelerator. Mostly, this seems to happens when car is at operating temperature as this has never happened when the engine is still cold (i.e. before the needle hits half)
I do many short trips (office is approx 6kms from where I live) as well as frequent long distance trips (i.e. +500kms twice per month)
I have done the following work on the car itself thus far to try and eliminate the random hesitation issues but still has not resolved the problem.
BMW E46 - 318ti Compact (2003) with the N42 engine (1995cc) 4CYL with 160,000kms on the clock
Replaced all spark plugs , did coil/spark plug test/ complete oil change with new oil filter, new air filter, new fuel filter, new petrol pump, replaced slightly leaking water pump, replaced O-Rings on solenoids (SOLV), cleaned throttle body, cleaned MAF.
Diagnostic work conducted
Spark Plug / coil check – No difference, all working fine
Replaced Fuel Pump
- Assumed this to be primary cause but ignored for quite a while until the car died on me. Wouldn’t start, wouldn’t move – no motor running sound when turning ignition on. Replaced it with a new one, car was fine again. I thought this solved the problem.
- When the car did it again at an intersection, I literally dragged my way through my right turn while oncoming traffic waited patiently for granpa to get a move on.
Solenoids/ (SOLV) replaced the O-rings
Throttle Body – cleaned inside TB with carb cleaner recommended by dealer, only cleaned inside opening to the TB, not the back as I did not remove it from the car. Very little to no visible carbon deposits. – Made no difference.

Mass Air Flow (MAF) Cleaned with some carb cleaner. Have worked in and around this area and have not come across any air leaks/vacuum leaks.
Fuel Filter (With fuel pressure regulator)
- Undercarriage of the car shows the car had been driven in very dusty areas. Assumed this to be a likely culprit, so swapped It out with a new one.
Many forums suggest CCV as I have to top up with about 500ml to 750ml of liquid gold (fully synthetic Castrol) for approximately every 700-1000kms I do on the car.
Other potential Culprits???
CCV – I have done small tests, just not sure how to ascertain what suction is correct, i.e. from normal idle, if I remove the oil cap – idle quickly gets erratic, almost like it is sputtering and unhappy and you can sense the car trying to correct this by increasing revs slightly but the car does not stall. Dipstick – removing dipstick – you can sense a slight change in revs, and putting my finger to it, there is indeed suction.
After replacing the fuel filter, I left the engine idling for about 20-30 mins, to get to normal operating temperature to make sure cooling fan was working. When I got in to accelerate, there was a HUGE PUFF of smoke billowing from the exhaust / no sweet smell so I know for certain it isn’t a blown gaskset/no milky residue in oil filler cap at all/no overheating.

Cam sensors – no idea how to diagnose these

CCV Vacuum – how exactly do I measure what is excessive or not? Or how do I diagnose this ? In any case, how would the CCV create an “intermittent issue” with hesitation – wouldn’t this carry on for a while?
I literally have no idea what to do with this thing. I keep thinking the Throttle body randomly gets stuck or CCV causing higher than normal oil consumption or Cam shaft sensors – NO codes at all being read from the BMWHAT app (Android) via the Bluetooth OBD II Reader.

Can anyone point me in any new direction to resolve this because I cannot afford to keep her if this persists…

 

[DieselFan]

Valvetronic motor? loss of power?

Idle control valve? possible stalling?

Hopefully some who knows this car will chip in as I have no idea.

Did diagnostics not bring up any errors?

 

[Chucky]

Calling LZ:fencelook:

sounds like a sensor issue no idea where the cam sensors sits on this motor but if you find another 318i(Face Lift) or ti just try swapping it from that motor and see if the performance of your motor improves.

another possible culprit could be the crank sensor giving in, that one is a bit of a mission to get to, as i know the intake has to come off to get there.

for good measure have you alternator checked esp the voltage regulator.

 

[andrewp2014]

Calling LZ:fencelook:

sounds like a sensor issue no idea where the cam sensors sits on this motor but if you find another 318i(Face Lift) or ti just try swapping it from that motor and see if the performance of your motor improves.

another possible culprit could be the crank sensor giving in, that one is a bit of a mission to get to, as i know the intake has to come off to get there.

for good measure have you alternator checked esp the voltage regulator.

hi Chucky..
Thanks for input, i agree - it could be a cam sensor/crank sensor issue- do i particularly need to replace it or can i just remove the connector and see what the car does by prompting Limp mode without it connected or will that cause harm/damage? if i think about it, a cam sensor on its way out simply gives a lower signal which would suggest chronic persistent problem though - Am i right? because my issue is intermittent - i.e. happens once every 20 or so trips i make and is usual when the car has been idling for a while, i.e. in traffic or very slow moving traffic/ issue never happens before engine reaches operating temp? Same issue applies to crank sensor?

Also - im using BMWHAT app (Android) and ELM328 Bluetooth to pull OBDII Codes, but no codes show up leaving me further baffled. I will pull codes again this afternoon and post result if any new codes have shown up ...

RE Alternator: i have an amp and sub without a capacitor - but even with the amp/radio fully OFF; the internal cabin lights flicker whenever i accelerate - radio has a surge protector if current drops below 13 volts (i think) so radio would cut out before volts drop too low to a point where car doesnt have enough juice to start the car... Still cant explain flickering lights when i accelerate so you are right, i should do the test. Will do this and post result,

Thanks a stack!raise:

 

[Straight six]

hang in there brother

You are not alone

I drover mine away from an auto electrician today after changing all six coil packs(as he had stated)..and the car was still hesitating.....

it all happens when normal operating temperature has been reached...

with a proper bosch alternator(standard sound), changed plugs,injectors,PCV....

 

[Ralf*]

I don't know about disconnecting the cam shaft sensor, on my E39, the cam sensor was faulty and it just woudn't start, never mind drive.

Your hesitation sounds similar to the problem (although nowhere near as bad) on my E38

I disconnected the electrical connector from the MAF, and most problems of stalling etc dissapeared completely,
Not that the MAF is at fault, but disconnecting the MAF has forced the cars computor to go into the most basic of modes, ignoring many of the sensors.

It still hunts ever so slightly, and has an intermittent misfire or judder. and the fuel usage is on the high side, but being a V8, that is already high in any way.

I might get "shot-at-dawn" for saying this, but consider disconnecting the MAF via the electrical connector, and see how it goes.

Your statement of

Mass Air Flow (MAF) Cleaned with some carb cleaner.

has me worried, as these components don't seem to take too well to cleaning especially with the incorrect fluids and/or methods

 

[Straight six]

is it safe to drive with connector on the MAF disconnected??

 

[zaleonardz]

Ok.... This is pretty simple...

VVT, nothing more nothing less.

There is a motor that controls valve lift, N42 was the first motor BMW made that had this, it was, sorry to say, but I have no better word for it, a fsckup.

The VVT controller is not even integrated into the main computer, it was a retrofit BMW did.

Now, you could be lucky and its just your VVT motor on its way out, and your in for like 6k with fitment, your average mechanic can do the job but you NEED bmw diagnostics software, at the very least INPA to calibrate the motor.

Start with the VVT motor, parts price is about 4 from agents, and a decent mech should not charge more then 3 hours to install.

Do NOT buy a second hand motor from a scrapyard, do not buy a pirate, one from the agents

More then likely, you are going to find however that your life sucks.

WHat actually happens is that the mechanism that controls the valve lift is actually worn out due to high km's, and you need to replace your head complete. From BMW thats going to cost at least a kidney and a liver.

OR...

I have heard rumours about actually locking the mechanism and removing the VVT, have never done it, but have it from a reliable source that it works

Remember you are talking mere mm in valve lift thats giving you your stalling issues,

Go research VVT, on this forum specifically, I have done quite a bit of research on the issue.

But start with the VVT motor,

---

Oh and its not a crank sensor issue, if it was crank sensor failure, car would not run at all.

You have two cam sensors, it could be one of them, they are the same, but trust me on this that its VVT

 

[Ralf*]

is it safe to drive with connector on the MAF disconnected??

:thumbs:

for over a year now already on my E38

but

in the long term not good, as Alexander explained to me, the engine is now using too much fuel, which actually washes the cylinder barrels, and thus reduces the lubrication of the rings within the barrels.

and LZ has also replied with a good solution, although this is another job altoegether.

 

[Straight six]

:bravo::bravo::bravo:

Information buffet....

Thanks Gents

 

[andrewp2014]

hang in there brother

You are not alone

I drover mine away from an auto electrician today after changing all six coil packs(as he had stated)..and the car was still hesitating.....

it all happens when normal operating temperature has been reached...

with a proper bosch alternator(standard sound), changed plugs,injectors,PCV....

Sup Straight Six!
Where abouts are you and what motor are you running? Its tough to keep up with these beasts especially when there are literally hundred of things that could cause hesitation. is yours chronic/persistent hesitation or intermittent? Potential Culprits after all you did in the above i would say, are down to
Vanos: beisan systems sells a kit for DIY recon. pricey but its made a huge difference in my friends e46 M3, much improved throttle response!
Cam/Crank Sensors?
MAF: just spray and clean but use the right stuff. disconnect it entirely to prompt limp mode and see if the car improves,
TB: Same as above, get the right stuff and give a decent deep clean to the throttle body + ICV
(assuming you have done air filter etc already) Could also be air leak - check housing and pipes, make sure fuel pressure regulator is connected to air filter correctly. Unlink and spray ALL of your terminals to make sure they have correct contact.
Perhaps fuel pump pressure? Fuel filter?
will let you know if i can think of anything else - let me know what resolves issue if you do figure out what loving your stunner is in need of?

---

I disconnected the electrical connector from the MAF, and most problems of stalling etc dissapeared completely,

Your statement of

Mass Air Flow (MAF) Cleaned with some carb cleaner.

has me worried, as these components don't seem to take too well to cleaning especially with the incorrect fluids and/or methods

Sup Ralf,
will try this tommorrow when i have the day to play around with it and will let you know. Will disconnect maf entirely and post results.
Used blutetooth ELM327 and android BMWHAT app to pull OBDII codes, suddenly i get

Engine/Motor (1 Fault)
Ambient Temperature Sensor/ Ambient temperature sensor, Plausibility/External temperature Sensor, Plausibility.
2f99

.... any idea if this could be related to the issue? because trying to research this on the net has been ridiculously irritating now?

---

VVT, nothing more nothing less.
More then likely, you are going to find however that your life sucks.
WHat actually happens is that the mechanism that controls the valve lift is actually worn out due to high km's, and you need to replace your head complete. From BMW thats going to cost at least a kidney and a liver.

OR...

Remember you are talking mere mm in valve lift thats giving you your stalling issues,

Hi Zaleonardz
... as for life sucking so badly, me and my wallet have just had the biggest argument EVER, hell, we might even break up after this... and i unfortunately dont have a pre-nup agreement.

Needless to say, im probably going to need to see a psychologist after now having to take into consideration the possibility of VVT. Will research forum on VVT issues and see what i can come up with.

if it is the VVT, again, wouldnt the hesitation be a recurring/persistent issue - my issue is entirely intermittent... happens once for every 20 trips i make and only when engine is at full operating temp/ usually in slow moving/thich traffic etc... ideas?

 

[Straight six]

I'm based in Cape Town:thumbs: