06 BMW 520d manual - sluggish acceleration, hesitation, no power in low revs, hiccups

pliauskiux

Hi guys,

I've got 2006 e60 520d manual (140k miles) m47 engine and I've been having issues with the car being underpowered in low revs for a few months now.
I bought the car 3 months ago and a few weeks later I've noticed that the car is seriously underpowered in low revs. Wasn't paying much attention to it initially as I thought it's normal. Moved onto this 163bhp version from a 105bhp passat so it really didn't feel like anything was wrong with it.

• The car accelerates very slowly below 2k RPM but drives fine afterwards.
• Rev needle also acts weird. Let's say I'm driving at 2.6k revs, If I get my foot of the accelerator for a second and then put my foot down again, the rev needle jumps up about 50rpm, jumps back down to 2.6k again and then slowly raises up as it should. This happens very quickly and cause 1 second lag. Add this to sluggish acceleration in low revs and the thing is a death wish as it has stalled on intersections and other dangerous places before.
• It also feels like it's hiccuping. I can feel sudden decrease in power for a split second around 1.4-1.8k revs and around 2.5k revs (sometimes). Usually until it's driven for 15-30mins or so.

Car has had a full service done 2 months ago.

In the past month a few things have been done to the car trying to sort out the problem:

1. Crankcase breather changed to vortex type
2. MAP sensor replaced
3. MAF sensor cleaned using EGR cleaner
4. New glow plugs
5. EGR/Throttle body/intake manifold cleaned, swirl flaps blanked off
6. DPF has been removed physically + in the software, EGR blocked through software

Only 1 error stored as of now, 1 glowplug gone (again).

Initially thought it could be MAP/MAF sensors, swirl flaps, EGR valve or the Crankcase breather, nothing helped.

The only thing that actually helped increasing the performance was getting DPF removed, it kept getting blocked and I was losing boost as the turbo wouldn't kick in until 2.8k revs or so. I got the boost back after 1.8k revs but still dangerously underpowered under 2k.

Some people have mentioned that the problems I'm having could be caused by:

• Faulty MAF sensor
• Turbo actuator
• Turbo itself

All the help is greatly appreciated. Thanks!

Waterson

Has your 'mechanic' checked the mechanical timing of the engine? No parts required and can be done without disassembly with a decent scantool using camshaft to crankshaft synchronicity comparison.

pliauskiux

Car has been scanned, the only visible problem was MAF sensor, as it wasn't showing accurate data.

Took the car for a drive with scanner connected, rail pressure fine, turbo a bit late than it should be. Everything else seemed fine.

MAF sensor has been disconnected, driven for a mile or so, no noticeable change in performance.

From what I understand, it's possible that MAF sensor is the root of the problem. I assume that if it was working fine and has been disconnected, the car would definitely drive differently, while it didn't seem to do anything on my car. New MAF sensor can go up to €270. Will try getting my hands on a known good MAF sensor and see if it changes anything.

Waterson

Perhaps suggest the MAF is tested prior to replacement. Depending on what setup your mechanic has, ask him to log live data from MAF on a quarter mile 0 to 60 run from closed to wide open throttle. It might offer some insight.

pliauskiux

Just posting my updates here in case somebody is having similar issues.

MAF sensor has been changed, no big difference in performance below 2k RPM but definitely noticeable difference after 2k.

Drove it for a few days, only felt it hiccuping a few times right before it hit 3k RPM, other than that the hiccups that could be felt around 1.4-1.8k and around 2.5k RPM are no longer there, and recently they were appearing 9/10 times.
Car drives evenly, no longer getting random bursts of power and hiccups.

It has also been scanned after MAF sensor change, readings from it seem to be a lot more accurate than the old one. Fuel consumption seems to be slightly better than before.

Still having issues with hesitation below 2k RPM, but it's not as bad as it used to be.
Also rev needle still jumps up and down when foot is put down on the accelerator.

wandererz

Have you changed the fuel filter?

Try a can of Clean Drive when the tank is at 1/4. See if that clears things out.

pliauskiux

Yes, fuel filter along with oil/air filters etc. were changed about 5000km ago/10 weeks ago.

I've also used injector cleaners/fuel treatment (from redex I believe, 2 blue bottle pack from halfords) a few times, tried using fuel from different garages also, didn't seem to make a difference.

What's that clean drive you have in mind? Could you send me a link to the product where I can read more about it?

Zcott

Needs a new clutch.

pliauskiux

Zcott wrote: »

Needs a new clutch.

What is your reply based on?

1. hiccups
2. struggling acceleration
3. rev needle bouncing (in any range at all times when foot is put down)

Also just to add, release bearing is noisy, flywheel was done 4 months ago, right before I bought the car, surprisingly neither clutch nor the release bearing was done at the time of flywheel change.

wandererz

pliauskiux wrote: »

What's that clean drive you have in mind? Could you send me a link to the product where I can read more about it?

In your case it's a bit of a long shot but here's a link.
https://www.partsforcars.ie/pfc-special-offer/cleandrive-advanced-fuel-exhaust-system-cleaner/

It's about €20 for a single can.

I have a basic code reader for BMWs if you need to have the codes read again.

I would suggest posting in one of the UK BMW forums. Lots of great info and experience available there. Do that first.

Another thing I would suggest is taking the car into a BMW specialist and/or a remap diagnostic center.

If not, (and this is a slightly expensive option) then consider a superchips Bluefin remap.
It can always be reversed by yourself (mybluefin.co.uk).

In my case it smoothed out the power delivery and increased power on a 2.0L m57 engine.

Caliden

Was the car remapped by the previous owner?

James Bond Junior

I tried those injector cleaners before and the only thing that really cleaned them out was a bottle of dipethane in a quarter tank of diesel.

pliauskiux

Thanks for your reply guys.

Since my last posts, turbo has been replaced with a refurbished one and it made a slight different in how the car drives, hiccups are gone, no more oil is being consumed, no more exhaust gas smell in the car, and no more whining noises that could be heard before. Overall, slightly better performance after 2k revs as expected.

On the top of that, car has been remapped (hasn't been remapped by previous owners @Caliden) and is now a lot better to drive, obviously. Still hesitates in low revs and is painful to be driven in traffic as it's very jerky and just a super slow car until it reaches 2k RPM.

I'll be bringing the car back to the guys who did the turbo within the next few days as they're quite knowledgeable and seem to know their stuff, I suspect there to be some sort of an air leak just because of how the rev needle bounces up and down the foot is put down, they mentioned it could be a crack in exhaust manifold or some broken vacuum pipe, it's all guessing at this stage, I'll see what they find.

Will keep the thread updated with findings for anyone else having similar issues.

drunkmonkey

Check the big fat rubber pipe at the bottom of the radiator, if that has worn or is slight off it'll cause some of those symptoms.

pliauskiux

drunkmonkey wrote: »

Check the big fat rubber pipe at the bottom of the radiator, if that has worn or is slight off it'll cause some of those symptoms.

Will have the real mechanics inspect the pipes, thank you!

minzabud

I have the same issue under 2k with an is220d, I just live with it at this stage as it sounds like a money pit to sort out.

pliauskiux

minzabud wrote: »

I have the same issue under 2k with an is220d, I just live with it at this stage as it sounds like a money pit to sort out.

Too right. There's so many things that could be causing these issues, it's just that after all the time, money and effort already spent on the car - I'd like it to drive the way it's supposed to drive. For all I know it could something as small as crack in a 30 quid pipe, who knows.

Eugene1976

Hi any update

Toyotafanboi

Hi Eugene,

If you are having issues, feel free to start a new thread, it's unlikely the OP will reply to this.