smurf520i

Hi All,

Wondering if you can help me.

My car is now 6+ years old, with only 16k miles on the clock, bought it brand new.
Apart from normal servicing and new wipers, everything else is stock.

The issue is this:
On summer mornings, the car starts and holds at about 1,000 rpm. Nothing wrong with that.
However, with air-con OFF, it shakes badly (for better wording) for about 10 seconds, as if it cannot decide what revs to keep idle-ing on.
It then goes back to normal and the issues does not re-occur until the next day.

With air-con ON, this issue does not happen or it is much less noticeable.

The truth is that I have had this issue from brand new but it is getting more prominent.

Thanks.
E60 520i

inktoxicated

mine has 36k does it once in a while too. i think its gonna stall or something then it goes away

porksoda

i had this problem on my e39. Turn out was injector seals and also some of my injectors were cracked. Easy way to see when its stalling have the bonnet open and see if you smell petrol/gas. Another symptom of injector seals/injectors would be hesitation occasionally while driving.

Besides that it could be bad gas... sparks or coilpacks.

tuffluck

exact same problem. thought about taking it in under warranty. it doesn't do it when the engine is just cold (like when i leave from work), only does it when the engine is cold in the mornings. very odd.

Howitzer

The worst thing you can do to your car is not drive it enough after that many years.

Diamond

My .02 is the following

1.I think one of the possibly likely culprits is carbon build up on your fuel system from lack of driving and especially lack of hard driving-jus my guess-the old Italian tune up seems to be a good idea here-basically floor it every chance you can on a good sretch of freeway-a goo 100 miles of that and you should be able to burn off some of that carbon.

You can also buy chevron technron fuel additive which is what bmw repackages and uses and run a few bottles through-1 with each tank. I would concentrate it more like use the 20 gallon bottle in 15 gallons of fueld--

Clean your MAF sensor with CRC MAF cleaner-

That is all easy cheap stuff before going to a dealer.

There are a bunch of things that I dont even have a clue about--my dealer ended up raising my idle a little bit to smooth out my rough idle--you may have a faulty idle control module as well.

that is where I would start

smurf520i

Firstly, thank you all for responding.

Back to the issue...
I just cam from a 800 mile trip (in 4 days) and I pushed it quite hard. So that cannot be the issue.
Forget about my earlier air-con statement, it stuttered this morning with air-con ON!

Short of me searching the forum inside out, what is the MAF sensor, where is it, and where can I get a CRC MAF cleaner?

The idle (at 600 rpm) is smooth, once it gets there. We're only talking about 10 seconds on summer morning starts (around 18 degrees celsius).

Thanks

Diamond

Sorry to say but years of not driving is not cleaned out by a long trip with occasional pushing it. I am talking flat our flooring it consistently for a bunch of miles as well as using the techron additive. This fuel cleaner will be shot with max pressure through the fuel system, injectors and will have the best chance of cleaning them out. Carbon is not easy to get off-may take weeks of driving very hard.

ALternatively bmw offers a more involved fuel system flush/clean for 150 bucks where they actually flush cleaner through the system with pressure-I did this at 30k and was worth it

I have always had a nice smooth idel and cant even tell the car is on.

the crc maf cleaner can be bought at any auto store, autozone, pep boys etc or online

The MAF is your mass airflow sensor-it is on the tubing out of your air intake box screwed on via two torx screws-you have to unscrew and pull it out, being careful not to touch the sensor "which is an exposed wire at the bottom of the thing" You then spray the heck out of it with the cleaner which instantly evaportes and is made for this purpose. You spray all sides and all angles-this gets rid of microscopic debree that is messing with the accuracy of the sensory-if it is even slightly off you will get the wrong amount of fuel injected at idle or low rpms. Once you get moving it really is the MAP sensor which is pressure in the plenum that control fuel delivery but the MAF does the idling

porksoda

atleast in canada... warranty they wont cover anything unless the part is falling off or you have a cel or something that can be seen heard as a failure.

Try smelling for gas in the morning.

MAF does not fail this quickly... i have had cars for 6+ years with zero maf failures. Most of the time dealers wont take the time to diagnose issues and will patch things up... if they think to increase idle to set higher will solve the issue they will.

All vehicles have something to the effect of an auto choke so the rpms do start high and will come down automatically.

The stutter in the morning when the car is cold is basically a subtle misfire but not outside its normal working parameters. It can be many things but obviously someone who knows the car well can troubleshoot. The seal was a big item for e39 as while cool the rubber contracts and does not provide a good seal, it wouldn't happen when car is warm as rubber expanded. Could be plugs as well.

The additives is basically snake oil... anyone who knows anything about injectors and additives know its just very high octane fuel that advances/retards timings and you get the illusion of "cleaner system" the effects usually wear off after 2-3 full tanks.

Unless you use really really dirty gas... injectors wont have "carbon buildup" either. It is true that carbon can be builtup in the chambers but there is 0 you can do about it without taking the engine apart. Also whether you drive hard or granny it will only effect the driver profile and the computer will adapt. This will NOT cause stuttering or magical carbon deposits or magical maf failures.

Scottnsd54

I had this same problem on my 550i...My mechanic says there is a delay in the timing of one of the variable lift valves. Its highly noted in various forus online, especially with the M5. BMW says its a delay in mixture of fuel and air... i disagree. However, give your car a little rev when it starts and the problem usually will go away.. It happened right in front of a bmw service administrator and he said the master mechanic said it was normal. Although, it never happened on my 530..just heard its a problem with the V8 and V10.