I have a R56, 2007 with 65K miles. I bought the car three months ago and supposedly half-way through its service interval.

It's a fantastic little car. As it’s been getting colder here in Utah I've picked up a CEL, 1497. I keep the car in the garage at night so it doesn’t get too cold. The CEL initially came on after leaving for work, driving for three miles at 65MPH and then coasting down the off ramp. The CEL popped on and the computer pulled timing and boost. There was no noise like detonation or valve train rattle. I assumed it was only a misfire with the computer dealing with the increased air density of the colder air. After work, the car started fine and I drove home thinking the CEL would clear itself out.

I got home and checked the oil, it was two quarts low! Thank you BMW and your stupid service recommendations. I added a couple quarts of Mobile 1 5W30.

I called the dealer the next day and asked if the plugs had been changed at 60K miles, they showed no records of the plug replacements. I ordered the correct spark plug socket and NGJ Iridiums ILZKBR7A8G. The plugs should be here tomorrow.

I went to O'Reily and pulled the code, P1497 (vacuum leak behind the throttle). I don't see any oil leaks or hear any vacuum leaks. A cracked valve cover seems kind of stupid but would be an easy fix with some JB Weld. I cleared the code and the car drove perfect for a few days.



During another cold morning, I again came off the freeway keeping it in 6th and rolling with no throttle at about 1800-1500 RPMS. The CEL light came on again. It may be a vacuum issue since vacuum would be highest with engine braking at a low RPM, such as slowing down while coming off the freeway in high gear.

Yesterday it got down to 30 degreesF and when leaving work the engine had a hard time idling until it warmed up. The engine didn't die it just went down to 800 RPMS and adding throttle didn't help increase power until about 3,000 RPMS. I drove the car again today and it still feels like it's in limp mode, barely making any boost.


I'm hoping that the plugs are worn out and are making it more difficult to idle when cold. Also, the car has aftermarket silicone intercooler hoses (APC, AEK, or something). I may need to go through the hose clamps and make sure all the grub screws are tight- although a leaking intercooler hose wouldn't make for a bad idle since the throttle is off the manifold and down line form the turbo and intercooler.


What does the Peanut Gallery Suggest the problem(s) may be?




Thank you for the help!

 

I think it's a valve cover leak. It's a known issue and there is a new/updated valve cover available. You should be able to search the forums here and find the threads.

According to what I remember it was an easy replacement.

 

It would be good to know what exactly is wrong with the valve cover and where it cracks. A composite valve cover with a hairline crack would be really easy to fix rather than spending $400 at the Stealership.

I put in my new NGKs last night and I examined the valve cover.
Two of the factory plugs had electrodes that looked slightly deformed by the heat. Spark plugs can have many unseen issues such as cracked electrodes in the porcelain that have trouble transferring the spark when cold, as soon as they heat up the electrodes expand and the issues goes away.

As far as the valve cover, nothing seemed askew. I started the car looking and listening for any vacuum leaks. Other then the injectors and valve-train noise I couldn't hear or see anything. I parked the car outside in the cold 20 degree air and checked again a couple hours later. No issues and the car idled butter smooth.

I drove the car to work this morning and it feels 100x better. There is no hesitation and it's quick to make boost.

Two of the factory plugs did look a little deformed by heat.

The trouble code and CEL were still there, I'll clear them out as soon as I have a chance to get a scanner.
I'll let you know how she does. I'm still hopping that the rough idle was caused by almost dead and cold spark plugs which in-turn caused vacuum issues and the P1497 code.

 

Any chance we can get an update on this? Mine is doing something similar. I just took it to the dealer 2 days ago for the timing chain and apparently I had a valve cover gasket gone bad, so they fixed that. Prior to going, I felt as though that car wasn't making quite as much boost as it usually would. I never got a CEL though, but it's almost the exact same circumstances. Even after replacement, it still feels like it's got no boost.

 

My car is still having issues. I replaced the plugs, changed the oil, and then took it into the dealer. The dealer told me that the intake tube had split at the the compressor intake. I had noticed this earlier but I didn't think it was leaking. The dealer told me this would account for the vacuum leak.
Secondly the dealer thought that possibly water had accumulated in the charge pipes and that the inter-cooler system would need to be disassembled and cleaned out. If water was accumulating at the throttle body then ICE could cause the throttle valve to catch. The dealer didn't take the time to check the fuel pressure, when I asked the tech about it he explained that CELs weren't consistent with a failing high pressure fuel pump. The dealer reset the computer clearing out all codes and allowing for the computer to relearn. Total cost $347.

Five days later, the check engine light is back and boost and timing have been pulled again by the computer. I have a solid CEL.
The car is starting better now, no rough idle but I am getting the same vacuum leak code. The issue continues to be the same, the car stumbles below 3,000 RPM driving around town and on the freeway. I don't know if it is a fuel issue, throttle body issue, or just the computer pulling too much boost so that the car loses its lower-end torque.

I am just going to have to fix it myself.

I noticed that there is some hard silicone peaking out from under the valve cover which could indicate that someone did not replace the valve cover gasket properly and used silicone instead. This may account for a vacuum leak under the valve cover. There also seems to be a slight oil leak in this area. I cleaned off the oil and will be examine the area to see if there is any fresh oil.

My next plans are:
1. Order the proper valve cover gasket and reinstall.
2. Go through and clean out the intake manifold and throttle body, possibly cleaning out the intercooler pipes.

As for your car. If there was no CEL, then maybe the dealer didn't reset your computer? The car will eventually relearn for max performance but it will take quite awhile. You may want to take it back to the dealer and ask them to reset your computer.

 

Any news? I have the same issue with the same procedures..please update me

 

Well, without the history on your vehicle and its services performed it could be a hunt or what many service techs would consider a shotgun approach to solving your issue. My guess honestly, at one point or another in your vehicles history prior to you owning it, i'm almost certain the vehicles Intake Manifold was probably removed (possibly for carbon cleaning service). Many techs are lazy or just plain don't know and do not replace the gaskets/seals for the intake manifold (which should be replaced anytime the IM comes off) which with time will cause a small vacuum leak that can be frustrating to pinpoint. It usually doesn't occur right away, but if the manifold has come off at any point in the vehicles history its a good chance your vacuum leak may be occurring there.

 

The intake manifold hasn't been pulled out since it was bought
I checked for vacuum leakage and i didn't find even in the valve cover it first threw p115c then after cleaning MaF it threw p1497

 

You may have a failed crank case vent valve. You can check this by removing the oil filler cap with the engine running. There should only be a light vacuum and the cap should be easy to remove. If it is difficult to remove, your crank case vent valve has failed. You may also hear a swooshing or sucking noise when the engine is turned off. The crank case vent valve is integrated into the cylinder head cover and can not be replaced separately. When replacing the cylinder head cover gasket, the factory repair is to use sealant in the corners on the drivers side of the engine. Hope this helps.

 

See my other post, it was the timing chain. One of the cams had skipped a tooth and added too much overlap while reducing vaccuum. I installed a new timing chain and guides and now the car is fantastic.