spark plugs,injectors, hpfp or what?

My 09 535i cpo,49000 miles has been in the shop several times for a rough idle. Sometimes it appears the car is going to stall then the cars shakes briefly then the idle is smooth. It happens intermittently but is happening more frequently, Everything was fine until the dealer changed the plugs at 45k. Dealer says its not throwing any codes and that a car with this many miles will have a rough idle. Puma case was started 2 visits ago. Any recommendations/help is appreciated..

Originally Posted by Gila06

My 09 535i cpo,49000 miles has been in the shop several times for a rough idle. Sometimes it appears the car is going to stall then the cars shakes briefly then the idle is smooth. It happens intermittently but is happening more frequently, Everything was fine until the dealer changed the plugs at 45k. Dealer says its not throwing any codes and that a car with this many miles will have a rough idle. Puma case was started 2 visits ago. Any recommendations/help is appreciated..

Well, I'm a newbie, but I may actually be able to add some value finally.

I just had a horrible experience with my injectors and subsequently a control module that controlled the HPFP.

My car had the same symptoms as the ones you describe. Then eventually it threw up a lot of warnings. It ended up being the injectors for sure, with other problems to follow. From what I learned it could certainly be your HPFP though. Mine didn't throw any codes dung the stage yours is in (unless they were lying when they sold it to me). My advice would probably not be advisable to many members here. You are under warranty, correct?

Yes . My base warranty runs out next month then the cpo kicks in. So i should ??...

Originally Posted by Gila06

Yes . My base warranty runs out next month then the cpo kicks in. So i should ??...

Listen, I need to preface this by saying all I currently do on this forum is learn and I have no BMW specific experience when compared to many other posters here.

The problem I had seemed to be expedited and exacerbated by accelerating quickly. I bought a BMW because it is built to be pushed and anyone at the dealership I bought from must be forced to go through a course that requires them to repeat "you can't hurt these cars, they are meant to be used for performance." I am rough on cars anyway. If I had your warranty I would want to have the issue fixed as soon as possible. Based on my experience and learning, the problem is not predictable but once the failure starts you can certainly speed up the process.

Of course, this is all assuming that your dealer is not willing to be proactive about the situation and is telling you they don't know what the problem could possibly be even though a guy on a forum that has owned a BMW for two months could probably diagnose it. It took about 3 minutes for posters here to evaluate and pretty much accurately diagnose my issue while I was still waiting for a tow truck. The dealership-- "Oh, it could be many, many things." A week later-- "Oh, the problem is [insert exactly what was said in my thread]"

I don't know. I don't like lingering issues with cars. If a dealership won't act on the issue because it is not bad enough I would find a way for it to be bad enough (without cost to you, in your case).

Check the MAF sensor.

I had the same problem with my 07, car would have rough idle, RPM would jump up and down and car even turned off when at complete stop.

Instead of replacing the MAF just yet, I took it out, sprayed it with an electric parts cleaner put it back in and voila!! car is smooth as new, no rough idle.

its a cheap and easy fix. doesn't hurt to try !

Originally Posted by GSG1

Check the MAF sensor.

I had the same problem with my 07, car would have rough idle, RPM would jump up and down and car even turned off when at complete stop.

Instead of replacing the MAF just yet, I took it out, sprayed it with an electric parts cleaner put it back in and voila!! car is smooth as new, no rough idle.

its a cheap and easy fix. doesn't hurt to try !

The n54 does not utilize a maf sensor but a tmap sensor to measure air pressure flowing into the intake plenum.

Originally Posted by Gila06

Yes . My base warranty runs out next month then the cpo kicks in. So i should ??...

The cpo warranty will cover your power train repairs so you should be covered. Since the dealer replaced the plugs it could be injectors, hpfp, or carbon buildup on the intake valves. Did you pull the codes yourself to see what fault codes are popping up? Usually there will be certain codes that show up for specific issues and that will give you a better idea of what you are looking at.

Thx for the replies. No codes is what the dealer is saying...

Originally Posted by Gila06

Thx for the replies. No codes is what the dealer is saying...

To help with the repair process having stored codes help the dealer with a starting point. Have you just started your car and let it idle, without touching the accelerator pedal? If you haven't try to park your car outside on a cold night overnight, then start the car and let it idle for 10-15 min to see if you can get a cel light. This worked for me when I was having long crank times and a stumbling idle. It finally threw multiple misfire fault codes which led to 6 new injectors.

I will give this a shot. Thanks for your help. Ill post what happens

Originally Posted by Gila06

My 09 535i cpo,49000 miles has been in the shop several times for a rough idle. Sometimes it appears the car is going to stall then the cars shakes briefly then the idle is smooth. It happens intermittently but is happening more frequently, Everything was fine until the dealer changed the plugs at 45k. Dealer says its not throwing any codes and that a car with this many miles will have a rough idle. Puma case was started 2 visits ago. Any recommendations/help is appreciated..

The exact same thing happened to my CPO around 44K miles. 1st, dealer replaced HPFP (found out this was the 2nd or 3rd one). It still happened, so they said that it needed a carbon cleaning. Was told that BMWNA wouldn't cover it, but since I bought it CPO and only owned it 2 months they would try to get it done. They did it at no charge to me. It still had rough idle. They then replaced injectors, plugs and probably a few other parts. It is fine now, 5000 miles later. I was told that it would have cost over $5000.00 if I had to pay.
My car has 49,200 miles and is in the shop today for it's last "free" service, but I feel that it is hard to trust it.
Wifey saw 2013 3 series and said, "want to trade it for that"! Deciscions, decisions...

SB55, i feel the same way..

It continues ! My SA says nothing is wrong with the car since its not throwing any codes. The car randomly idles rough and the rpm flucuates. I escalated the problem to the shop forman and he wants to drive the car for a few days. Im at 49500 miles,cpo, and really want to get this resolved. Again, the problem started after the 45k plug replacement. I took the car in about two months ago, and the SA said they walnut blasted, and checked the spark plugs,put in new ones, and put the replacements back in because they couldnt find a problem. I drive about 20k a year. Im taking it in on wednesday for the 4th time for this issue. My best friend has the same car and he hasnt experienced anything like this.

I really like the car but im not sure whats going to happen when i come to a stop or when the car is idling. Why wont the car throw a code when it almost cuts off or when it idles rough? I only use premium gas and mainly no ethanol gas.

The two other bmw stores are about 1.5 hrs north and 2hrs south. Its time for tires but im not sure ill keep the car. I did see a 2010 for sell out of state.


Sorry for the long post , i just want the car fixed.

Ideas ?

Have you tested out how quickly the car can accelerate? Drive it like it's stolen for an hour. See what happens. You're under warranty, but not for long, right?

Its cpo to 2015.

What are you waiting for then? Make it throw up some codes.

Do the cold start thing someone mentioned. Keep it in sport mode and *safely* push your boundaries. Have some fun.

Originally Posted by Gila06

Its cpo to 2015.

That's good that its covered till 2015. The other thing you can do is put the engine under a heavy load. You can do that by going about 40mph then put it in 3rd gear going WOT till redline then shift into 4th. Of course do this in a safe environment since 3rd gear will take you up and over 80 mphs.

I will try that tonight. Its a 6mt though. Thanks again

Booyaazaa, i got my eye on a white one it this doesnt work out...2010

Originally Posted by Gila06

Booyaazaa, i got my eye on a white one it this doesnt work out...2010

I personally don't like the alpine white, JK.

If it's rough idle, not throwing code, sluggish and worse than normal fuel mileage, I'd say clean the intake valve by means of walnut-shell blasting. Big dealers know how to do this, it varies from $400 to $800 to do it. If they refuse, ask them to take the intake off to see the inside, if the valve clean at least you have a peace of mind (for the cost of 1-hr labor and valve gasket unfortunately, but I almost ready to bet money your intake valve is gunked up like picture 1).
GL.

Originally Posted by HPIA4v2

If it's rough idle, not throwing code, sluggish and worse than normal fuel mileage, I'd say clean the intake valve by means of walnut-shell blasting. Big dealers know how to do this, it varies from $400 to $800 to do it. If they refuse, ask them to take the intake off to see the inside, if the valve clean at least you have a peace of mind (for the cost of 1-hr labor and valve gasket unfortunately, but I almost ready to bet money your intake valve is gunked up like picture 1).
GL.

The OP stated that the dealer already did that 2 months ago along with plugs.

Originally Posted by booyaazaa

The OP stated that the dealer already did that 2 months ago along with plugs.

I thought that was "sb55" not "gila06" that got walnut blasting at no charge, Gila06 only got plugs replaced @45k. My bad if I misquoted, hard to read line per line on all posts

My 08 535i is having the same idle issues and it started after getting the spark plugs replaced around 64K miles. I will be bringing it in within the next few weeks and will let you know what they find out.