Got a few underbonnet questions...

[e34.535i.sport]

Query 1...
Had a bit of a rattling noise for a while now. Been doing some searches and a few people had had strange noises due to loose spark plugs... I checked each one today and all were nice and snug. Checked the condition of #1 spark too just incase and it looked perfect.

Initially I thought it was related to the AFM so I checked the operation of the door and no problems there - really clean too surprisingly enough.

I used the good old 'ear on the end of a screwdriver technique' and have located the noise in the fuel rail somewhere... It sounds like a really plasticy sound so I would guess a plastic clip or something inside? Going to take the plastic cover off tomorrow and I just wanted to check if its ok just to take off - or if I need to be aware of anything first? The clips on the outside of it seem like they may be brittle too. Any ideas what can be rattling under there? I've never had the cover off before you see and a bit dubious about it.

Just to clarify there are no problems in the car's running, no power/fuel/start issues (it takes a second or so to start but I assume this is normal).

Query 2
I wanted to give the ICV a clean today as the idle is quite rumbly (if thats a word)... At the risk of sounding like a fool I'm going to ask - how the hell do you get it off?! I undone the hoseclamp on the air pipe that hangs off the bottom of it but didn't get much further... I know, I know, newb .


Query 3
I took the airbox off while looking at the sparks and HT leads, and when I looked down near the strut housing I saw two connectors that had been disconnected... One was like a three-pronged type and the other was different so they definitely didn't fit together but they were next to each other. WTF are they is my question?! I'll try and take pictures tomorrow becasue it is bizarre they way they're just there but not connected to anything. They seem to lead back up to the big box where the EAT chip and that goes (My technical vocabulary seriuously needs to improve).

Thanks for any help in advance...

[Paul in NZ]

the injectors themelves can be noisy.

[Adnan]

Hi,

If by plastic cover you mean the injector wiring harness cover, it's unlikely you will find anything in there that will rattle. If memory serves, it's just a mess of wires and boots where connectors come through. When replacing injectors, or to access the fuel rail itself (buried under the harness housing), you just have to yank on the harness housing. Looks like a nasty thing to do but it does work (prying judiciously helps). I don't think there are any clips inside that can break off.

Were you listening at the harness cover or the actual fuel rail? If the rail, then one or more injector may be noisy.

Perhaps I missed an earlier post on this, but there are many kinds of rattling noises that can emenate from under the hood. One particularly annoying one is actually the dual mass flywheel clunking along sporadically at idle. The other is "flicker" of the layshaft in the gearbox, which is harmless; it tends to be more rhythmic than the flywheel. The radiator fan also comes to mind as a possible culprit.

Happy hunting.

Regards,
Adnan

[e34.535i.sport]

Hi,

If by plastic cover you mean the injector wiring harness cover, it's unlikely you will find anything in there that will rattle. If memory serves, it's just a mess of wires and boots where connectors come through. When replacing injectors, or to access the fuel rail itself (buried under the harness housing), you just have to yank on the harness housing. Looks like a nasty thing to do but it does work (prying judiciously helps). I don't think there are any clips inside that can break off.

Were you listening at the harness cover or the actual fuel rail? If the rail, then one or more injector may be noisy.

Perhaps I missed an earlier post on this, but there are many kinds of rattling noises that can emenate from under the hood. One particularly annoying one is actually the dual mass flywheel clunking along sporadically at idle. The other is "flicker" of the layshaft in the gearbox, which is harmless; it tends to be more rhythmic than the flywheel. The radiator fan also comes to mind as a possible culprit.

Happy hunting.

Regards,
Adnan

Hey there thanks for the input... I just put the screwdriver on the wire harness cover and could definitely hear the noise coming from there. I'm now wondering whether this needs to be stuck down more securely, maybe it has become loose? I'm hoping the injectors aren't faultering, as I don't really fancy that job at the moment! It sounds very much like plastic, so I'm pretty sure something around there has gone amiss.

You speak of the Dual Mass Flywheel clunking along sporadically at idle I didn't mention about that but I get the feeling I have this also, but only rarely. It won't always happen so it doesn't bother me too much, but it is bizarre the way there is no pattern to it and it only starts doing it once a fortnight or so (Total guess - rough estimate?)! Is it a really bad thing if it does this, can I just live with it and not worry?!

[e34.535i.sport]

Hate to reply to my own thread before anybody else but just found an old thread I had saved on removal of the ICV (query 2)... Think I have this down now, should be able to sort that tomorrow hopefully!

[Ferret]

Hey there thanks for the input... I just put the screwdriver on the wire harness cover and could definitely hear the noise coming from there. I'm now wondering whether this needs to be stuck down more securely, maybe it has become loose? I'm hoping the injectors aren't faultering, as I don't really fancy that job at the moment! It sounds very much like plastic, so I'm pretty sure something around there has gone amiss.

You speak of the Dual Mass Flywheel clunking along sporadically at idle I didn't mention about that but I get the feeling I have this also, but only rarely. It won't always happen so it doesn't bother me too much, but it is bizarre the way there is no pattern to it and it only starts doing it once a fortnight or so (Total guess - rough estimate?)! Is it a really bad thing if it does this, can I just live with it and not worry?!

Is this a 'rattle' or a 'ticking' noise?

The injectors on the 535i by this age are usually pretty noisy and make a continuous din, like those old bits of plastic people used to stick in their pushbike spokes

As to query 3, you'll be finding connectors like that all over the car - dont worry about them, they're usually for an optional extra that's just not been installed!

[e34.535i.sport]

Is this a 'rattle' or a 'ticking' noise?

The injectors on the 535i by this age are usually pretty noisy and make a continuous din, like those old bits of plastic people used to stick in their pushbike spokes

As to query 3, you'll be finding connectors like that all over the car - dont worry about them, they're usually for an optional extra that's just not been installed!

I wouldn't say its a tick... more of a rattle. It hasn't always been there but only recently started noticing it, but any unusual noises play on my mind at times. It could be what you say about the pushbike though - difficult to fit a description to it! I'll have a good look tomorrow and see if I can 'see' anything amiss. If its a noisy injector I'll just live with it I suppose until it starts giving me a problem!