Ducmaniak

Ok, I have searched this forum and others with no definitive solution. When I initially start the car, the idle bounces from about 700-1000 RPM, then after about 4-5 minutes it stops, but the idle stays at 700-750 regardless if the air is on or not. The only code that is thrown right now is P0491 Secondary Air System Bank 1. I have the y-pipe and will be changing it as soon as I have 4 or 5 hours to do it. Could this cause the idle issue as well?

I have changed air filter and cleaned MAF. I tried unplugging the MAF and it will still have the same issue, just not as drastic.

Ducmaniak

I also just replaced the Idler pulley and tesioner pulley as they were on their way out. No change. Any advice?

dawid_w

Did you replace pressure regulating valves already??

https://5series.net/forums/topic/109..._fromsearch__1

Ducmaniak

Nope not yet. They are cheap, on order. Thanks for the advice.

Wolrab

Mine were changed by the dealer, shortly before the warranty ran out. I never heard why. They have hoses to the intake. I never knew if the originals did or not.

Ducmaniak

Thanks for the suggestions, I just changed the valves out last night. the new ones did not have the nipple for the breather tube, so I plugged the tube on the intake. This morning still had the same problem. Any ideas?

NyC545I

Hi, I have a '09 550i and I have a similar problem, I went to Motorcepts (well known shop in this forum ) and they changed 2 ignition coils & plugs. The car was hesitating and shaking at red lights and also idling crazy between 500-700rpm, now it runs nice and smooth but in the morning it still idles crazy for 5 min. and today on the way home the check engine light came on! WTF? I had a 2005 545i with 98,000miles that never gave me a problem! I love the E60 , I thought a smart move would be to sell it and jump into a newer E60 would save me money on repairs due at 100k come to find out this 550i that I just got 2 months ago is already giving me issues. Oh forgot to mention My recently purchased 550i has 51,000 miles and to top it off my old 545i which I sold to my friend is still running strong, no issues what so ever since I sold it to him 9 months ago! From what I read 550i's are more reliable than the 545i? I know I have to do major service at 60k but is it common for parts to start to fail at 51k? I thinking it may be the MAF does anyone know what the price would be for a new one?

Thanks everyone for allowing me to vent.

Ducmaniak

I have a 545 an the cheapest bosche MAF I found is about $300. Kinda pricey for a what if scenario. Just today I was thinking about the coils, but I would assume that it would throw a code, unless that is the one item they aren't monitoring on the technological beast. I personally don't think it is a coil because it only does it at idle and settles down once the engine is warm. In the mornings it usually doesn't happen, typically at the heat of the day and if the AC is on, it's that much worse. Maybe only 5-10 minutes and then stabilizes.

Ducmaniak

Could it be an AC issue? Was just thinking that if the compressor is kicking on and off because of improper pressure, that could cause the rpm to fluctuate. Thoughts?

mrfva

How many miles do you have on the car?