E39 540i - power loss, sounds like Subaru!?

[tangalife 1]

Had a problem arise this morning. Car feels like its running on less than 8 cylinders, feels like it’s just about to run out of gas, sounds like a Subaru boxer engine would be the best way to describe it. At idle it feels fairly normal though. I also noticed that when I went around two roundabouts this morning (so fairly hard turning) the drive belt started squeeling and applying resistance to my turn, exactly how when your running low on steering fluid and you try and turn the wheels hard right and left and it will squeak.

 

I’ve had the following symptoms for the past while:

 

• Rough idle every now and then, usually on cold mornings, hasn’t happened much recently though.

• Some weird pulsating when cruising around 1900-2000rpm, you can hear a soft grinding/gurgling like noise and a slight pulsing, almost like it cuts out for a split second every 2 seconds when held at this rev range. Feels like a fuel issue?

• Car stalls when come to complete stop or on a hard turn at very slow speed. This has only happened a handful of times so it’s not regular.

• Lately the car will lose all power for about a second and then kick straight back in, usually upon acceleration, sometimes the traction control light will switch on after this so it’s like someone hit the traction control button mid-acceleration.

 

I realise I probably need to take this in but im at work for the whole day so thought I would test my luck on the forums first, it would be great to tackle this myself this weekend. I'm hoping it's maybe just a bad coil or something like, in which I can test tonight when I get home to rule that out.

Edited September 14, 2016 by tangalife

[qube 3568]

I think it sounds like a airflow sensor issue but best thing to do is get it properly scanned for fault codes before anything.

[tangalife 1]

I've always suspected the MAF. I've cleaned it a couple times but I guess if its faulty, cleaning wont do anything. I have a cheap scanner, I will be chucking that on tonight also.

 

[Michael. 2312]

Boxer WRX sound from a V8 usually indicates it's running like a V4 or similar. 

1UZ V8 Toyota engines I deal with do that when one of the two coil packs fail (each does 4 cylinders)

However in your case it sounds like something else has failed that controls half the cylinder firing, likey the DME

Yours has 8 individual coil packs and igniters on each cylinder so its unlikely those are the issue (they just don't fail all at once!)

[*Glenn* 854]

Fault codes will head you in the right direction if the scanner is capable of giving you the right fault codes. A blocked or partially blocked cat can also give the same symptoms

[tangalife 1]

33 minutes ago, Michael. said:

Boxer WRX sound from a V8 usually indicates it's running like a V4 or similar. 

1UZ V8 Toyota engines I deal with do that when one of the two coil packs fail (each does 4 cylinders)

However in your case it sounds like something else has failed that controls half the cylinder firing, likey the DME

Yours has 8 individual coil packs and igniters on each cylinder so its unlikely those are the issue (they just don't fail all at once!)

Another common problem with DME is when your traction control lights, abs etc come on by themselves right? This used to happen every so often a while back, could also explain the sudden power loss/traction light coming on as I described above. I really hope its not DME, from what I've read, that's bloody expensive.

[*Glenn* 854]

You really need to get this scanned with a proper scanner and by a person who actually knows how to evaluate the fault codes correctly and has an understanding and experience dealing with this model

[Michael. 2312]

Agreed ^

Haha 

 

[BreakMyWindow 1870]

Do you have the vanos v8 ? 

Based on my experience with your symptoms it was a failed camshaft position sensor.

 

grinding sounds and pulsating in that rev range can be the torque converter failing. 

 

abs, traction control lights coming on is usually a wheel speed sensor or the abs module itself.

 

you really do need to get it scanned though.

[tangalife 1]

No not Vanos. Its 1997 model. Hopefully getting it scanned with a good scanner tommorow. In the meantime I just got home and ran my scanner thru.

70 Camshaft Position Sensor

4b Misfiring with cylinder cutout, total

3e misfiring, sum relevant to exhaust gas

Activation Map Cooling (picking this is separate as I often get the check coolant level msg on my dash)

 

Edited September 15, 2016 by tangalife