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So i'm stumped. Car is running very rough at idle, ticking noise and it wants to stall.

  • I've replaced Spark Plugs \ Ignition coils
  • DISA valve exploded, passed through intake. Replaced disa valve, recovered broken pieces of flap.
  • Oil changed as well

Car : 2008 BMW 328i

Mileage: 155k

UPDATE:

DISA valve self-destructed and sent two pieces of flap through the intake manifold and landed on the top of the valves. Nothing got through the valves and was able to recover both complete pieces of flap and metal pin. DISA was replaced & car still rough running. Possible this damaged the valves? Any way to verify this?

Compression Test Results

Cylinder 1 - 190

Cylinder 2 - 190

Cylinder 3 - 160

Cylinder 4 - 190

Cylinder 5 - 0

Cylinder 6 - 170

Broken Flap

https://i.sstatic.net/pmFO9.jpg

Below is a video of the engine running

https://www.youtube.com/watch?v=J6_iup0fJ18&feature=youtu.be

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  • Welcome to the site! This is a great question :) Do you have any fault codes?
    – George
    Commented Mar 25, 2019 at 11:49
  • Managed to pull the codes, currently receiving the following: 1. DME: Combustion misfires, Cylinder 3 2. DME: Combustion misfires, Cylinder 4 3. DME: Combustion misfires, Cylinder 5 4. DME: Combustion misfires, Cylinder 6 5. DME: Combustion misfires, Several Cylinders
    – James Vargan
    Commented Mar 25, 2019 at 17:08

1 Answer 1

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As George suggested, check for fault codes if you can.

In my own opinion, this noise could sound like hydraulic followers ticking or another camshaft related component noise, but to be sure, you could use a strobe light synchronized with your engine, to identify the frequency of the noise, if it happens at every revolution, it's probably a crankshaft related noise, if it happens every two revolutions of the cranckshaft, it's probably a camshaft related noise.

If you don't have such tools (I do not have such tools), you could drive the car downhill (if there are hills around you, else try on the flat) engine braking, or shutting the engine off, just to see if it stops when there is no explosion, if it stops, the noise probably come from a crankshaft related component (crankshaft bearings, connecting rod bearings, piston pins)... (I hope it doesn't), it could mean there is clearance between some crankshaft or pistons related components and the explosion in the cylinder pushes one of these components against the other because of this clearance, making a knocking sound.

If you can still hear the noise without explosion, it's certainly caused by the camshafts or the valvetrains, it could be failing followers (I assume yours are hydraulic), or bent valves that are not closing correctly for instance, increasing the valve clearance and making the cams knock.

Hope it helps.

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  • I'm thinking its possible the valves bent. The DISA valve on the outside of the intake manifold self destructed and sent 2 pieces of flap through the intake manifold and into the valves. Nothing got passed the valves and I was able to recover all the pieces of the broken flap and metal pin. How would i be able to verify bent valves or not? Image of broken flap i.imgur.com/7kKR3TWl.jpg
    – James Vargan
    Commented Mar 25, 2019 at 17:41
  • If you have a mechanic stethoscope (if you don't, a long screwdriver will do the job), you can place the metal end on different points of the engine and listen to where the noise sounds the loudest (with the screwdriver, just put your ear on the other end). If it seems to come from the head, I would remove the head cover and gently try to push the valve followers down when the cams are up (you can turn the crankshaft by hand with a wrench to rotate the camshafts). If a follower is floating, even slightly, there something wrong with this valvetrain. You could also check the valve clearance.
    – Alex
    Commented Mar 26, 2019 at 7:24
  • If you own a compressiometer, you could perform a compression test for each cylider (I should have told you that before to remove the head cover), a loss of compression in one or more cylinder would indicate that their not correctly sealed. If you really think that some head components are the culprits, and you're at ease with head removal, you can remove the head to check them directly.
    – Alex
    Commented Mar 26, 2019 at 7:35
  • Managed to check the compression, not good. Cylinder 1 - 190 Cylinder 2 - 190 Cylinder 3 - 160 Cylinder 4 - 190 Cylinder 5 - 0 Cylinder 6 - 170
    – James Vargan
    Commented Mar 27, 2019 at 22:20
  • Yes, cylinder 5 is leaking, this may explain why your engine wants to stall, and why you've got some misfires in it. This leakage could the result of one or more bent valves in cylinder 5. Do you plan to fix it yourself, or to have it done for you ?
    – Alex
    Commented Mar 28, 2019 at 8:03

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