[alx.]

Hello guys,

Sorry i didn't take the time to present myself yet, i promise i'll do so when i get home from work tonight with pictures and everything. I did read on this/use the search thread but i am very desperate.

Having some trouble with my n52b25 that has driven me to the point of giving up and selling the car(even though i wouldn't since i love the thing). When the car warms up it starts to have an erratic idle/pulsing. Also when pulling away i get surges and the WOT is close to non-existent...When revving the car from idle it starts to shake at about 1800 RPM and when it comes back down the pulsing starts again.

I have changed: 6x bosch spark plugs, 6x bosch coil plugs, vanos solenoid replaced with OE + cleaned the one that wasn't throwing any errors, reset adaptations of the car so it can re-learn, cleared fault codes(had the solenoid error for the exhaust but it never came back after replacing the solenoid). What could it be? I would really appreciate any input as i am at the end of my wits. Could it be the eccentric shaft sensor? I understood if that one fails due to the oil inside of it it will also cause start-up problems. Disa valve? What else should i check next without having to throw two salaries at it?

Thank you in advance for taking the time to read.

[bNks334]

update to the latest software before you go spending any more money on parts. Idle issues and fluctuations have been addressed in several ecu updates.

[alx.]

Thanks bNks! Mine's a 2006 without the nav, I am assuming only the dealer can update the software, correct?

[bNks334]

Yes, the dealer can do it. Not sure about cost outside of warranty though.

[Three_thirty_I]

How often is the oil changed? What's the car's mileage? Have you inspected the Eccentric Shaft sensor's plug for oil leaks? One thing that could also play a part although you have already replaced one of the Vanos solenoids is the Check valve filters that can get all clogged up - they filter and feed the oil to the solenoids and Vanos etc.

Software update is also something to do, but I tend to think that unless the fuel has changed a lot, it shouldn't make too much difference unless it been suffering with this problem for ages.

Hope you are able to find the cause of this.

[alx.]

Thanks mate, I do 10.000 km or 6200k miles oil change intervals. Car's mileage is 158k miles. Previous owner would do 15k miles oil intervals from what i've seen in the service history but he would do mostly highway miles. 80% of my commute is in the city plus Bucharest is not known for it's fuel quality/clean streets which is why i won't risk it and do 7k top intervals of filters/oil.

[Three_thirty_I]

Originally Posted by alx.

Thanks mate, I do 10.000 km or 6200k miles oil change intervals. Car's mileage is 158k miles. Previous owner would do 15k miles oil intervals from what i've seen in the service history but he would do mostly highway miles. 80% of my commute is in the city plus Bucharest is not known for it's fuel quality/clean streets which is why i won't risk it and do 7k top intervals of filters/oil.

Now that you mention fuel - maybe consider a good injector cleaner added to the next few tanks. Also, have the Smooth Running test run via diagnostics to see if all is well. I had some muck in the fuel rail on mine that was causing an over-correction because injector 1 was being affected by this.

[alx.]

Originally Posted by Three_thirty_I

Now that you mention fuel - maybe consider a good injector cleaner added to the next few tanks. Also, have the Smooth Running test run via diagnostics to see if all is well. I had some muck in the fuel rail on mine that was causing an over-correction because injector 1 was being affected by this.

Fuel injector cleaners actually work? If so, what would you recommend? In hopes i'll find it here.

[Three_thirty_I]

Originally Posted by alx.

Fuel injector cleaners actually work? If so, what would you recommend? In hopes i'll find it here.

They help. Most advise using Techron, but there are other good brands out there too.

[alx.]

Originally Posted by Three_thirty_I

They help. Most advise using Techron, but there are other good brands out there too.

Thanks for the advice, first thing tomorrow i'll go get some injector cleaner. Btw, love your 330 vids your car sounds great( this is my first straight six and petrol). Owned a 320d e46 before.

[Three_thirty_I]

Originally Posted by alx.

Thanks for the advice, first thing tomorrow i'll go get some injector cleaner. Btw, love your 330 vids your car sounds great( this is my first straight six and petrol). Owned a 320d e46 before.

Thanks! NA six FTW!!

Keep us posted!

[alx.]

Hello Guys,

My mechanic called and said he found a cracked hose that leads to the disa valve. Hopefully this was the culprit. Will keep you updated after i've replaced it. Btw, if the disa is on it's way out does it throw a code?

[Three_thirty_I]

Originally Posted by alx.

Hello Guys,

My mechanic called and said he found a cracked hose that leads to the disa valve. Hopefully this was the culprit. Will keep you updated after i've replaced it. Btw, if the disa is on it's way out does it throw a code?

Maybe just double check what he means - there is no hose to any of these DISA units, there are cables that connect to them, but no hoses. He could be talking about vent hose that goes onto the PCV which is located on the intake, or any of the other vent hoses. Maybe a cracked intake boot is what he means?

[alx.]

Originally Posted by Three_thirty_I

Maybe just double check what he means - there is no hose to any of these DISA units, there are cables that connect to them, but no hoses. He could be talking about vent hose that goes onto the PCV which is located on the intake, or any of the other vent hoses. Maybe a cracked intake boot is what he means?

Could be,yes. It's difficult to translate to english to be honest . He will give me the part number tomorrow and i'll report back with the exact culprit!

[Three_thirty_I]

Originally Posted by alx.

Could be,yes. It's difficult to translate to english to be honest . He will give me the part number tomorrow and i'll report back with the exact culprit!

That's understandable. Well, keep us posted. Either way, hope it solves the problem!!

[alx.]

Thanks! Apparently these are the codes for the items i need, could any of these be causing my symptoms? That's all he found that was wrong, the eccentric shaft sensor seems to be in good shape, no oil in it so i replaced the gasket. Part numbers:

11617531423

11617559530

11157522931

11157567801

[Three_thirty_I]

That's the PCV and all (looks like all) the vent hoses. I suppose with the car's age and mileage, it's not a bad plan to replace all of these items. And if the PCV is blocked it could cause some issues, but I am not sure if it will cause the problems that you have been struggling with.

I am hoping other member will add to this and add their thoughts.

[alx.]

Thanks! Managed to register the car. First thing i did besides new winter tires(went with Nokian WR D4 205/55/16) was to fill up with 100 gasoline and added a fuel system cleaner. I still get the idling surge but the car does seem to be running better now, just that the surging idle is getting me desperate.

[Three_thirty_I]

Keep us posted. Hope things continue to improve.

[3002 tii]

Originally Posted by alx.

Thanks! Managed to register the car. First thing i did besides new winter tires(went with Nokian WR D4 205/55/16) was to fill up with 100 gasoline and added a fuel system cleaner. I still get the idling surge but the car does seem to be running better now, just that the surging idle is getting me desperate.

It might be your pcv

[alx.]

Originally Posted by Three_thirty_I

Keep us posted. Hope things continue to improve.

Thanks, hope so as well.

Originally Posted by 3002 tii

It might be your pcv

It's in the items i listed above, correct? The crankcase breather.

[matteblue3er]

I would check your MAF sensor.

Also check vacuum system and make sure it's operating properly/no lines are broken.