Loud clicking noise when idling.

[92E34]

So today was the last day of my reassembly of the M50 under the hood of my 525. I did a runup test and I'm getting an odd problem.

It starts fine. Idles fine and clicks. Just click click click right on the top of the engine. If I hold it at 3k it stays there for about 5 seconds surges to +500 rpm, then the engine shuts off. I can then immediately start it again and it has the same sound and issue.

The computer has no error codes.

Anybody have any ideas what it could be?

[Yiorgos]

Sitcking lifters?

[92E34]

Its a freshly overhauled cylinder head. It was clicking before when it didn't have any oil pressure, but it died down now that there is oil at the head.

[ThoreauHD]

Mine does that for about 10 minutes at start if it sits for a week or two. Just oil seeping through the cylinders, but the clicking goes away after it starts circulating and the exhaust gets clear. Just old engine wear. I don't have the clicking sound if I run it every few days.

[632 Regal]

recheck the valvetrain, check for loose spark plugs and leaky exhaust gaskets too.


Its a freshly overhauled cylinder head. It was clicking before when it didn't have any oil pressure, but it died down now that there is oil at the head.

[92E34]

I'm going to pull the valve cover off to check the cam just in case the lifters are stuck.

[stu1]

You probably know this but a big screwdriver in the ear can give you a good idea of where it is before you take the valve cover back off. But I don't understand the 500RPM surge you're getting...

[BillionPa]

after you narrow it down, throw some molybdenum disulfide in the oil, its an extremely low friction EP/AW additive and very good at making the top end shut the hell up... as long as you have proper flow of course!

[92E34]

I talked to one of my buddies that works on alot of bmw's today.

He said that the lifters could be out of adjustment.

Is this possible? I though Hydraulic lifters didnt need to be adjusted?

[Yiorgos]

Hydraulic lifters do not need adjustment -- that's the whole point of having hydraulic lifters in the first place.

He might not work on that many BMWs if he didn't know that ;)

[92E34]

I'm still going to take off the valve cover to see what the story is underneath.

The only other thing was the Injectors resistance is a little odd, it was 16 ohms for #6 but 13 for the other 5. Each injector has close to a volt of juice going to it.

I still have to check the coil packs resistance.

[BillionPa]

the difference in injector pulse strength would cause a lean condition in one of the cylinders, which cause valve issues over long term (carbonization)

[92E34]

Well I've got good news. Clicking went down. Now I've got a whole different problem.

Now the car misses when I hold the throttle down above idle. Before I had forgotten to tighten the Cam position sensor and made the problem go away for a while. Now its back and worse. I can't drive the car at all. Any pointers?

[stu1]

If you disconnect the MAF how does it run?
If it improves then you may have a vacuum leak between the MAF and throttle body.


(What was the problem with the clicking btw?)
Stu.

[92E34]

It doesn't run any better, well maybe slightly better. It idles at around 850 RPM. But it still studders if I hold it at an RPM.


Clicking was a lifter that didnt have enough oil.

[92E34]

Whats the normal Manifold Pressure reading?


I'm getting around 11 inches of mercury.

[tnt525i]

I talked to one of my buddies that works on alot of bmw's today.

He said that the lifters could be out of adjustment.

Is this possible? I though Hydraulic lifters didnt need to be adjusted?
hydraulic lifters have no adjustment correct,, but,, if when disassembling the head you remove the lifters and when reassenbling you dont insert the lifters in the CORRECT order you took them off in,,, well then you have a big problem of sticky lifters and noisy lifters etc,,, a quick fix for this is to replace all lifters with new ones or the other way is try finding the right lifters for each cylinder, now let me see thats 24 valves by 6 cylinders, i cant figure it out,, but its alot of time

[92E34]

hydraulic lifters have no adjustment correct,, but,, if when disassembling the head you remove the lifters and when reassenbling you dont insert the lifters in the CORRECT order you took them off in,,, well then you have a big problem of sticky lifters and noisy lifters etc,,, a quick fix for this is to replace all lifters with new ones or the other way is try finding the right lifters for each cylinder, now let me see thats 24 valves by 6 cylinders, i cant figure it out,, but its alot of time


I had a Head shop do all that. They are used by a BMW repair place not 10 miles from here. So I'm positive they did it right. And They did replace the lifters.

Well looks like I'm going to take it to someone for them to figure it out. I'm too pissed off to strip down the engine again.

[92E34]

I was reading a Haynes BMW Manual that covers the old Motoronic 1.1 systems and it says that the CPS might need to be checked. And then it clicked. I forgot to put on the impulse thingy on the back of the intake camshaft sprocket. Maybe that is the source of the problem.