Timing Chain - No Power to Airbags Z3 2.8

[DavidM]

My car - 2.8 1999 build - is running rough and I’ve been trying to get diagnosis - a local mechanic has told me the car is misfiring on 3 of the cylinders after running diagnostics - a small hose behind the MAF has also split.

His thoughts are the timing chain has stretched and more than likely needs replacing.

I would welcome comments / insights - could it be anything else - before I spend a fortune on this repair?

David.

 

[t-tony]

Would be the first time I have heard of this on a BMW engine. Nissan and some Toyota models it's quite common.

Tony.

 

[DavidM]

That’s what I was thinking, Tony - thank you for your reply.

 

[bear2020]

I have had loads of BMW's with timing chains not one have I ever replaced or been stretched. Only one I had to replace was on a vectra C diesel

 

[DavidM]

Thank you for your reply, bear2020.

 

[Eddie Zedder]

Vanos solenoid sticking or camshaft sensors may be a culprit.

 

[t-tony]

The E89 4 cylinder turbo have had some bad press regarding timing chain failures. This was mostly the early cars and later ones were fitted with modified chains and guides. The 6 cylinder engines have a reputation for being virtually bullet proof.

Tony.

 

[DavidM]

Vanos solenoid sticking or camshaft sensors may be a culprit.

Thank you, Eddie Zedder!

 

[DomiMik]

If there is a split hose I would check the whole engine for air leaks. Most of the hoses are old and can crack so there are a couple of possible places for leaks which can cause the engine to run really rough.

Last year at the first start after winter my engine was running poorly and wouldn't idle properly. Even at the slightest revving it would shake. After a quick search I heard a hiss just under the engine cover and found this hose to be leaking at exactly the same spot (borrowed the picture from the internet). Replaced it with a fuel hose until the new part arrived and everything was fine again.

 

[DavidM]

If there is a split hose I would check the whole engine for air leaks. Most of the hoses are old and can crack so there are a couple of possible places for leaks which can cause the engine to run really rough.

Last year at the first start after winter my engine was running poorly and wouldn't idle properly. Even at the slightest revving it would shake. After a quick search I heard a hiss just under the engine cover and found this hose to be leaking at exactly the same spot (borrowed the picture from the internet). Replaced it with a fuel hose until the new part arrived and everything was fine again.
View attachment 222283

Thank you for this, DomiMik!

 

[Lee]

Thank you for this, DomiMik!

Agree with every comment above, very unlikely to be the chain, more like a huge vacuum leak. Ask him to smoke test it.

 

[NZ00Z3]

Misfires are caused by Electrical and Mixture problems:

Electrical

• Plugs and coils. Swap with another cylinder to see if fault follows
• Harness. Dirty connectors, damaged wires, faulty coil earthing resistor
• DME. Inspect the 2 sets of 6 MOSFETS (Black boxes) around the outside of the DME PC Board for damage. Inspect for PC Board track damage. Any damage will be obvious.

Mixture

• Too rich. Too much fuel, not enough air. Faulty MAF or Pre-Cat sensor fooling the DME into thinking 1 or the 2 prior causes is happening, blocked Cats, O2 pilot mode on CCV, if the problem is bank specific, a leaking injector.
• Too lean. Too much air, not enough fuel. Faulty MAF or Pre-Cat sensor fooling the DME into thinking 1 or the 2 prior causes is happening. Vacuum leaks (see first tip)
• The DME has a performance tune. The DME tables may not match the MAF or injectors fitted. The Air/Fuel tables have been incorrectly altered. Put the DME back to its original tune and see if the problem is fixed.

Your problem is most likely a vacuum leak. That split hose is one, there are likely to be others. Check the fuel trims, if any are > 8% then vacuum leaks it is.

Smoke test the engine to find the leaks: https://www.e46fanatics.com/threads/how-to-smoke-test.1261077/

 

[DavidM]

Thank you all for your insights - I will arrange for further diagnosis based on the expertise that you all have provided!

David.

 

[DavidM]

Further to the misfiring problems on my Zed as mentioned above > resolved to fitting new spark plugs and air filter.

One added problem following diagnostics check - no power going to airbags displayed - I think it is a code 15 - may be wrong. Other than fuse would there be anything else I would need to check? I would welcome comments.
Thank you.
David.