W614 ML320 Ticking/Chuffing noise under load - Not injector?

[DaveyLC]

Hi Guys,

My ML makes an annoying Ticking/Chuffing noise only when warm and only under load, I've removed the air boxes, checked the injectors and I can see no evidence of a leaking injector?

I also cannot see any evidence of a cracked or leaking exhaust manifold..

Are there any other suggestions as to what this annoying noise could be?

Thanks!

 

[BlackC55]

It's tricky to say without hearing it. Can you post a vid?

 

[DaveyLC]

I'll try

 

[DaveyLC]

I've not been able to record the sound as its only possible to hear it with the windows open and then the wind noise is too much for the mic to handle..

I have noticed its only apparent when the car is warm and some times (when the noise is apparent) I also get a slight judder when pulling off.

 

[Mr Kripling]

Leaking injector seal?

 

[optimusprime]

Hi Guys,

My ML makes an annoying Ticking/Chuffing noise only when warm and only under load, I've removed the air boxes, checked the injectors and I can see no evidence of a leaking injector?

I also cannot see any evidence of a cracked or leaking exhaust manifold..

Are there any other suggestions as to what this annoying noise could be?

Thanks!

You may have a leak on the inlet manifold sucking air with the fuel.

 

[DaveyLC]

Leaking injector seal?

I can't find any evidence of a leaking injector.. I've had both air-boxes off and a good old poke around.

You may have a leak on the inlet manifold sucking air with the fuel.

I'd expect to hear lots of hissing too if that was the case

 

[Mr Kripling]

Can you smell any exhaust from the engine bay? I had similar symptoms on my Phaeton and the only evidence was a small amount of carbon on a small vent hole from the cylinder head. There was no evidence of any blow-past around the injector itself.

 

[DaveyLC]

No smells, no deposits (oily or dry).. And the noise is not apparent when the engine is not under load even if I rev it on the spot..

But it sounds exactly like a leaking injector as I drive.. Its driving me crazy

 

[Bellow]

But it sounds exactly like a leaking injector as I drive.. Its driving me crazy

At half engine speed frequency then? (The frequency - if you can define it - should give a clue to its source).

No smells, no deposits (oily or dry).. And the noise is not apparent when the engine is not under load even if I rev it on the spot..

Rolling road under just sufficient load to provoke it and a nosy around the engine bay to find it?

 

[DaveyLC]

At half engine speed frequency then? (The frequency - if you can define it - should give a clue to its source).

All I know is it sounds exactly the same as a leaking injector.. I had even bought the new seals and bolts, but on inspection I can't see any evidence of a leak

Rolling road under just sufficient load to provoke it and a nosy around the engine bay to find it?

Unfortunately I don't have one handy

 

[DaveyLC]

Today I've worked out the noise is only apparent when the turbo is boosting.

 

[SLKGirl]

I have a tappy noise going on to with my SLK, it's been there from new, it's only done 3000 miles, it rises with revs but can hardly hear it in the cabin, it's been back to MB twice, they say could find nothing wrong and is nothing to worry about, but couldn't tell me what it is... they say it's not even run in yet etc etc... sounds to me like being fobbed off?

Tried to record it, link below

https://www.youtube.com/watch?v=HmKU...ature=youtu.be

 

[DaveyLC]

That sounds like a 'sticky' hydraulic lifter.. How old is the car?

 

[DaveyLC]

On Saturday I decided to have another good mooch around in the bay and while I was at it I removed and cleaned the EGR, it was a right bugger to remove (as in well stuck) but on inspection not that badly coked up but I cleaned it anyway.

I could still see no obvious signs of injector leaking .

But I have noticed the following:

1) The noise is only apparent on very warm days or when I have been in traffic and the ambient temperatures in the bay are high.
2) It only happens during light-medium throttle and when the turbo is boosting.
3) The noise is also combined with a very slight jerking/rough running.

So its either a leak or the engine is pinking because there isn't enough diesel getting in or the injector timings are out (e.g. the ECU isn't being fed the correct inlet temperatures).

 

[awer21]

Hello. Have u find the problem? I have the same problem with a sprinter 519 from 2012. After different specialists I have changed untill now crankshaft sensor, dpf exhaust, map sensor, dual mass flywheel.
I think the problem is from ecu or injectors(i have checked them on a diesel specialist ,they are ok, but they cant reproduce as the car is under load and warmed).

 

[DaveyLC]

I've still not managed to work out what it is and on a cold day the car is perfect, no noise!

 

[awer21]

Hello again. I got a video and can you tell me if the sound is the same as yours?
...from 55sec

https://www.youtube.com/watch?v=x4YEiJQBLdQ

 

[DaveyLC]

Its hard to say, Mine really does sound like pinking or a leaking injector...

I've got a few other symptoms:

* When cold I have to wait for the glow-plug light to go out or it takes forever to start.
* If I'm stuck in traffic and the engine gets really hot it feels like the car is miss-firing at low revs under-load but its fine if I give it a boot-full.


BTW Are you still getting the noise if you floor it? On mine its good as gold if I floor it.. I'm really starting to think one or more of my injectors are duff.