Re: Thanks, a few questions... (archive)

3) Injectors always make a clicking noise. It's the solenoid opening the valve and the spring pressure closing it. On some it can make quite a racket. Not sure if it IS the injectors, just trying to give you sources to a noise that I can't hear!

4) Stretched chain would not rub against the valves, but it would rub/slap against the chain guide and tensioner. This could be due to a chain tensioner that is slow to pump up or bleeding out when the car if off. Do you notice this more when you park with the nose pointing uphill and the tranny left in a forward gear? This would cause tension on the belt (through the drive line) and would tend to collapse the tensioner piston. Not a major problem since it will pressure up when you start the car.

I'm working on a friends M5 where the tensioner collapsed in just the way described above. We got a racket when we started the car, unfortunately, the last time the racket did not go away and the tensioner needed replacing.

Hope this helps,

Don

Question for No 1) what do you mean by valves set?? the 525i M50 engine has self adjusting valves..

No 2) it's possible, but I only hear the knocking sound at idle or when I give it a slight gas and the knocking sound speeds up..

No 3) why do injectors make noise?? it never did this before

No 4) I think a stretched timing chain can cause this problem when it rubs up against the valves... and yes the M50 engine has a timing chain..

Thanks

Not sure I can help with the info provided, but there goes.

1) knocking sound where you describe it (engine cover - did you mean valve cover) is likely valve lash. When was the last time your valves were set?

2) Another source of knocking sound is preignition. Does not ususally happen during idle, but rather under load (so I'd rule that out).

3) Injectors can make quite a noise. As you accelerate the individual knocks kind of merge together and fade under the rest of the engine noise.

4) I suppose a chain (does this engine have a chain?) could make the noise you describe.

I'd listen with a mechanics stethoscope and try to pinpoint the noise. Failing a stethoscope, try holding a large screw driver to the various engine parts (be carefull) and press the handle portion of the screwdriver to your ear. See if you can identify the area where the sounds are the loudest.

Hope this helps.

Don

My car, a 1993 525ia is making a strange knocking sound inside the engine cover... Everything else about the car seems fine, engine idling very smooth, no noticeable vibration, good gas mileage, accelerates without a glitch.. I did have one strange experience coming off a highway off ramp to a standstill last week and the car hesitated and felt like it might die, and then started to idle slightly higher and problem went away.. Anyone have any ideas???

Thanks in advance.. Want to hear any opinions before I take it to my mechanic tomorrow morning..

Follow Ups:

Thanks, Problem diagnosed... Kenny 11:52 8/20/2001 (0)

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