Running lean? Adjusted AFM...

[e34.535i.sport]

Hey just interested in the long term effects of running lean? I'm not sure but think I have been.

I've just adjusted the AFM (half an hour ago!) and improved the idle a little. Still rumbly but better. It also seemed to quieten the injectors slightly. I turned the adjuster various amounts and waited noticing changes in the idle- 3/4 turn (or 270 degrees) clockwise seemed to optimise it. I didn't use an exhaust gas analyser. My thoughts are I can change it back if there is a problem so I'll test it out as it is.

The engine has seemed to have a 'drop' every few seconds or so at idle, not visible on the rev counter but audiable. So I was guessing this was a running lean issue... Related to my Idle thread I know but didn't want this post to get lost if you know what I mean! The car passed the emissions test a couple of months ago too well if you know what I mean. The maximum acceptable Carbon particles here is 1200ppm (parts per million) and mine came back with 39ppm. This seemed a bit fishy for such an old car with such a big engine! Opinions? My thoughts were its running lean hence adjusting the AFM. Do you think I've done the right thing here, I don't want to mess anything up?!

Anyway possibly related, I've also noticed a slight dripping from the exhaust for a while... I know about condensation etc but it has it when you wouldn't expect there to be any condensation i.e. hot weather and after running for a while. I touched the liquid and smelled my finger (can't think of a better way to put that sorry it sounds terrible) and there was no smell. Additionally, the sound from the exhaust at idle has 'gaps' in it. I don't know if this is normal but thought it best to mention it. Oh and when you stand outside the car by the drivers side door(RHD) you can feel a fair bit of heat once its been running for a while - anyone else get this?

I apologise if this thread isn't too clear, I can't seem to find the best way to describe things at the moment. :p

Any opinons/ advise gratefully accepted...

[nirvana19]

You engine sound anything like this?

http://www.youtube.com/watch?v=i6RRa-W9n3I

Ignore crazy squealing at the beginning of the video, its kind of hard to hear the rumble of the engine over the clicking fuel injectors but my engine seems to fit what you described. I don't bother with it too much.. it runs.

Oh, and my car also had very low emissions, I'll look up the actual numbers tomorrow but they were all WELL below the limits.

[vping]

Sounds just like mine.

[e34.535i.sport]

Hey guys good to know... I had a watch of the video and mine is definitely similar but not so loud with the injectors. That noise from the intake side is there too but less audiable - it seemed really loud on the video?

I think my exhaust is pretty similar the way its not 'regular' but maybe its normal?!

Anyway, if you haven't already have a go of the AFM adjustment, its free easy and seems to have given me good results. I took it out and on a 6mile round trip (70city:30motorway roughly) the OBC suggested I got 22mpg. I wasn't driving it for economy either, so I'm not sure if I've improved the economy or the computer is being given different readings because I changed the mixture. Besides the mpg I noticed the car was much more willing to accelerate from low end. It felt like I got some performance back and I don't think it was just 'seat of the pants'! Obviously the idle was a bit better too, so I think I'll leave it alone now... I've got bigger fish to fry anyway (New radiator to fit as well as some new Bilstein Sports!). Next project after that... got my heart set on some 19lb injectors.

[AngryPopTart]

Interesting stuff! I also have the idle that hunts or whatever. When you first start the car, when it's cold that is, the idle comes up and goes down and jumps up and goes down like 4 or 5 times before it settles, but the idle is still slightly choppy. If I rev it up after that towards 2k-3k it acts like it has to clear out or rather the computer has to make some adjustments because it doesn't want to rev up immediately. Like if I press on the pedal just enough to let the idle rise to say 2X00 RPM it will take a moment but gradually rise higher as the system clears out. It kind of acts like a carbureted car that is loading up. After letting it clear out over the next few seconds, the idle rises till it's revving smooth and then I can let it go and it doesn't tend to have the problem again.

Why do these have to be such nice cars otherwise. haha!

[nirvana19]

Hey guys good to know... I had a watch of the video and mine is definitely similar but not so loud with the injectors. That noise from the intake side is there too but less audiable - it seemed really loud on the video?

I think my exhaust is pretty similar the way its not 'regular' but maybe its normal?!

Anyway, if you haven't already have a go of the AFM adjustment, its free easy and seems to have given me good results. I took it out and on a 6mile round trip (70city:30motorway roughly) the OBC suggested I got 22mpg. I wasn't driving it for economy either, so I'm not sure if I've improved the economy or the computer is being given different readings because I changed the mixture. Besides the mpg I noticed the car was much more willing to accelerate from low end. It felt like I got some performance back and I don't think it was just 'seat of the pants'! Obviously the idle was a bit better too, so I think I'll leave it alone now... I've got bigger fish to fry anyway (New radiator to fit as well as some new Bilstein Sports!). Next project after that... got my heart set on some 19lb injectors.

The camera I used for that was quite mediocre, but it was all I had at the time. I think it amplified that sound on the intake side quite a bit. My injectors are VERY loud but seem to function normally (could be affecting performance or efficiency-dunno). Unless they fail I probably won't touch them for a while. I have a friend with an identical car (year, colors, etc.) except with a manual transmission. His engine is quieter in every way and has a much smoother idle. BMW master techs told me my engine is "perfectly healthy" so I'll with it for now, might try the AFM after spark plugs, etc.

[e34.535i.sport]

BMW master techs told me my engine is "perfectly healthy" so I'll with it for now, might try the AFM after spark plugs, etc.

You can't get much better reassurance than that!

My noisy injectors don't bother me too much, it's just the rumbly idle. It never bothered me until I changed to an EAT chip and after disconnecting/reconnecting the battery the car ran REALLY smooth at idle for a while, then returned to normal. Will change the injectors at some point or get them cleaned to put my mind at rest that they aren't causing it...

After the adjustment the idle is still better and its been a couple of days now...

[e34.535i.sport]

Idle is still better which is a good thing... I'm surprised it worked so well - I haven't had any negative effects.

Just on the off chance I had the key in position 2 today and lifted the bonnet. I could hear an electrical buzzing noise so I inspected further and it is coming from the ICV, and its vibrating too.You can only tell this by feeling it though, you can't see it vibrate. The electrical buzzing noise is a bit crackly too which is weird, haven't noticed it before. Normal or not anyone - does yours do this?

[AngryPopTart]

Just on the off chance I had the key in position 2 today and lifted the bonnet. I could hear an electrical buzzing noise so I inspected further and it is coming from the ICV, and its vibrating too. Normal or not anyone - does yours do this?

Mine does it... swapped it out with one off another E34 and it does it also.

[e34.535i.sport]

Mine does it... swapped it out with one off another E34 and it does it also.

Hey good to know thanks dude!

[whiskychaser]

The car passed the emissions test a couple of months ago too well if you know what I mean. The maximum acceptable Carbon particles here is 1200ppm (parts per million) and mine came back with 39ppm. This seemed a bit fishy for such an old car with such a big engine! Opinions?
Isnt 1200ppm max for an engine without a cat?

[e34.535i.sport]

Isnt 1200ppm max for an engine without a cat?

I hope I'm not being silly here but I don't think my car has one?! The guy at the garage didn't seem to think it did either... I've never noticed it if it does have one.

[whiskychaser]

I hope I'm not being silly here but I don't think my car has one?! The guy at the garage didn't seem to think it did either... I've never noticed it if it does have one.
It might not have one. In which case your results are pretty good. I think more modern engines kick out about 2ppm. Mine doesnt have a cat but it wasnt made for the UK. If you have a cat you also have an O2 (aka Lambda) sensor. These are normally in the exhaust manifold or a bit further down in the downpipe. Saves you crawling underneath if you are curious:)

[e34.535i.sport]

It might not have one. In which case your results are pretty good. I think more modern engines kick out about 2ppm. Mine doesnt have a cat but it wasnt made for the UK. If you have a cat you also have an O2 (aka Lambda) sensor. These are normally in the exhaust manifold or a bit further down in the downpipe. Saves you crawling underneath if you are curious:)

Wow that is low - I thought i was kicking asse with 39...

I am the curious type so I might just have a gander tomorrow for the o2 sensor... I know its an expensive piece of kit so hopefully I aint got one (more to go wrong!)...

[e34.535i.sport]

Just incase this comes in handy for anyone in future I found out that you can get a small allen key into the adjuster without even loosening the nuts that hold the AFM onto the cylinder head! You just need a small allen key (hex key) - the one I used is only about 2" in length...