Z4 Doesn’t start - making noise like it’s trying to turn over

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2004 2.2i

Hello, this happened a couple weeks ago was driving fine before then came out the next day to start and was making this noise, changed the battery and had a look at the spark plugs and they look fine. Any clue? [/url][/youtube]

Here is the inside and out of trying to start it
https://youtube.com/shorts/f2x_4B3qgcA?feature=share

[enuff_zed]

Oooh, not a nice sound.
To me it almost sounds as though the starter is slipping?

[BumpyZ4]

Man, that doesn't sound good. It sounds like a timing issue to me.

[Jas- USA]

You need to use a code reader and do a follow up posting on any codes which are listed.

[MEV Z4]

I don't think there's much point in doing anything until you have the compression test results.

I'd get buy a Compression Tester (About £30-£40) and see what figures you get for each cylinder.

Look up what the figures should be for your model and engine (Something like 140psi on ALL cylinders?)

I'm no expert but sounds like some of the cylinders are compressing and some are not - The other comments agree this is not a good sound.

On my E46 330 2004, I tried to start it one day and the engine whizzed - Compression results 30, 30, 120, 120, 120, 90
(Yours sounds different as it may have more compression)

My E46 had bent ALL the valves (Failed tensioner), I confirmed this when I got the head off and none of the valves would hold water.

NOTE - None of the valves looked bent but they ALL were, an endoscope inspection will not be adequate.

If you find low compression on some / all cylinders then possible causes could be - Bent valves, cracked piston head, serious engine overheating causing aluminium pistons to expand and wear away the rings so they wont compress / seal next day when rings have cooled and contracted, skipped / stretched chain, broken piston rings / stuck piston rings (Easy Fix - See Youtube video on pouring Redex in plug holes), loose spark plugs (Easy Fix).

Apart from the last two it will almost certainly mean the end of the car (Unless you're quite determined).

Have you got a 2.2? That engine is prone to chain skipping, which would lead to a lack of compression even if the valves survived. A skipped chain alone is still lead to a huge expense / engine write off and it's quite a task if you want to do it yourself - Whether the valves survived a skipped chain is a bit academic as you'd probably do the valves anyway while you're there.

I tested for chain skipping on my Z4 2.5 which has a different M54 engine (I was actually more interested in chain stretching).
There are good You tube videos from the 50's kid / Shoplife / Pelican parts etc. but this is how you test on the M54 engine.

Move the engine to Top Dead Centre which is when the front two cam lobes are pointing at each other, you can confirm by the timing mark and then further confirm visually by putting a screwdriver down the plug hole into cylinder 1 (Front Cylinder) and turning the engine until the piston /screwdriver are at max height. If you have the BMW timing tool kit you can put the crank lock pin in it's hole (under green plug by the starter motor) as well to confirm you're at top dead centre (Cylinder 1).

At that point look at the rear ends of the camshafts, you'll notice two Dots punched on the ends which are now both face up. Put BMW cam lock tool there (If you have the BMW timing tool kit). (See You tube videos on what the Cam Lock tool looks like). If the cam lock too wont fit then the camshafts are not in the position they should be when the crankshaft / cyl 1 is at Top Dead Centre and you have a chain issue. As most people wont have the camlock tool you can probably just look to see if the cam shafts are in the correct alignment (Both sets of Dots pointing UPWARDS in the SAME direction) and therefore whether the chains are OK or have skipped /stretched. (NOTE - In the highly unlikely situation where just the intake cam position was out then this can be adjusted - See You Tube Videos on Vanos timing)

(There is also an arrow on the front of the exhaust cam which must point to the top edge of the cylinder head if engine is at TDC and the chain is correctly aligned - You have to get the Vanos unit of to see it and it's still quite hidden under all the Vanos components - just saying).

A code reader wont be much help - It may say misfire on Cyl 1 (You know that already) or Air Monitoring issue (We know that already) etc.....


I don't think there's much point in doing anything until you have the compression results.

If the results are good then try new sensors / other causes / vacuum leak / fuel pressure test etc.

If the compression results are bad then you're looking at the above........