AW_530D

I bought a 2004 e61 530d with 111k miles on it.

Seemed fine and generally seems to run well.

However i noticed that when the cruise control is set and theres an incline the revs rise and fall slightly giving a jerky/rough ride.

I also spotted at idle the rev counter twitches cant hear any change in engine speed though.

Any ideas what might be causing this?

fletchedpair

First port of call is get the codes read and see if the car is registering any faults which can lead you straight to the problem.

May need an EGR valve clean, gets pretty clogged up with those miles. Also your crank case breather will need replacing, if you are on your original one it will be the old style membrane which gets clogged up. Whats the condition of your Diesel Particulant Filter?

AW_530D

Fired up INPA and got these codes:

Error codes
Module Code Type
12 DME/DDE 41D7 14
4226 02
4212 24
4242 24
4252 24
4276 32
4B10 11
4B11 12
4185 71
4BC2 94
4BC7 04
4BA0 01
4298 18

18 EGS 51AD 24

29 DSC 5F14 A0

3C CDC D811 20

40 CAS A0B2 20

47 ATTNU DAD3 20

60 KOMBI A3C7 20
A557 28
A3AC 20

72 KBM A444 60

73 CID A468 24

78 KLIMA 9C55 64
9C54 21


Cleared them and after a quick start stop im left with only glow plugs, i'll recheck the codes after a drive and heat cycle.

mjojom

I had a 4 out of 6 glow plugs, turned out to be control module, located under intake manifold.

AW_530D

Did a 100 mile round trip this weekend and re read the codes

3 glow plugs which dont bother me but I have:

DDE - 4B10 - Smooth running controller, correction quantity too high.

a google suggests this means 1 or more of the injectors has a fault.

I ran DIS with the engine off to read the codes.

Can I do any tests to discover which injector(s) are faulty?

mmitev

This is generally caused by deterioating torque converter in the auto box. It's a very frequent fault/problem.
- First line solution is to replace the gearbox oil, it helps to some extent.
- The complete solution however is replacement/overhauling(?) of the torque converter, which is more costly.
The good news is there is nothing urgent (if it is the converter indeed). It will get worse gradually.
If it bothers you a lot and if you plan to replace the converter down the line anyways, then it mjakes no sense to change the oil now, as later you will have to do it again with the torque replacement.

AW_530D

Sounds plausible, the torque converter lockup could be slipping.

Only things that makes me think its not is the rev counter twitches only very slightly where as I have seen videos of the rev counters swinging wildly, and I can see the counter twitch at idle in the same way some times. And I don't get the issue when driving myself, only seems to occur when cruise is set.

I'm going to resolve the issue with the injector(s) and see if that improves things.

I'm not getting the best MPG either which is a little disappointing.

mmitev

Sounds reasonable. Might be the injectors indeed under these circumstances.

AW_530D

Thought I would test the torque converter lock up since you mentioned in.

On the motorway the other night I banged it into manual and selected 6th at 70mph

Carefully watched the rev counter and opened it up a bit, can see it doesn't stay relative to speed, it jumps up suddenly then slips back down a bit and is generally not very smooth. Looks like the torque converter wasn't locked or is slipping.. would you agree?

When I selected auto again it seemed to drop back to 5th as the revs were over 2k at 70mph where as in 6th they were below that, can only assume it was DPF regen.

1Animal1

note on the glows - if your doing short journies they WILL improve your MPG if they are all working.

I've done a lot of testing trying to get rid of the above problem whilst trying to sort mpg issues out, replace an item then run it for a week etc - replacing the glows made my car heat up a lot quicker despite being told by many that they are only for start up - this is true on older diesels, not modern ones

Good luck on your twitch