Excessive engine vibration.

[bonbon]

I have excessive engine vibration - especially when put in gear when stationary. (Automatic). Already changed all mounts.
The only code that comes up is the MAF.
Makes sense?

 

[Grumps]

It could have thrown a fan blade. They go brittle and fly off when driving causing massive vibration.

 

[bonbon]

It could have thrown a fan blade. They go brittle and fly off when driving causing massive vibration.

I feel it when stationary...

 

[colb]

Bad Maf may well cause rough running and show up as vibration, it will mess up the fuel trims causing rough running. If your going to replace the Maf only use Bosch or siemens oem brands do not buy cheap ones, they rarely work well.

 

[ChrisD]

If you have a MAF code then it makes sense to address this first. It may or may not fix the vibration issue but it should be the first step on your diagnostic path.

 

[Grumps]

I feel it when stationary...

You would do, It did when my went.

 

[bonbon]

Ok - I have two spare (used) Bosch MAFs. They made no difference.
What other faults can a MAF code indicate?

 

[ChrisD]

If by no difference, you mean the MAF code is still present? So, if not the MAF sensor itself then possibly wiring/connections. Knowing what P-code you have would help.

 

[bonbon]

I need to get the reader again. But perhaps I'm just being anal in my old age.
Who has a M44 1.9 Automatic?
When stationary idle and putting into D(rive), does vibration increase?

 

[ChrisD]

I don’t have an auto so going out on a bit of a limb here:

The M44 engine has a notoriously rough idle. This is because to meet FE/Emissions numbers for certification BMW had to take out fuel and reduce the idle speed as low as they could get away with. My manual M44 had a ‘rough’ idle from new, when I looked into it I found out the dealer ‘fix’ was to just increase the base idle speed. I didn’t want this so have grown to appreciate the lumpiness at idle - at least I can feel that the engine is running!
With an auto, putting it in drive will increase the load at idle and make a poor situation worse.
Obviously you’d be better advised by someone with an auto but even then people’s perceptions and tolerances vary wildly. You may well get someone with the exact same issue as you telling you theirs is perfect.
If you can see variations in the idle speed on the tacho then that, to me, indicates something is wrong. Or if has become significantly worse recently. Otherwise it may just be what it is.
In any case, fixing your MAF issue can only help matters.

 

[bonbon]

All your words are of wisdom.
I have a new hunch. A few months ago my garage put in new engine mounts. I don't know what make they were (I will ask).
Are there differences in quality/stiffness that can explain my recent experience of "excessive" vibration?

 

[ChrisD]

Oh hell yes. Engine mounts are tuned to the particular characteristics of the engine they are supporting. If they haven’t used the OEM specified parts then that may well exacerbate the issue.

 

[bonbon]

I'll find out what they used (no way Corteco which are OEM)
See table from ChatGPT:

 

[FLZ_Boy]

Was the transmission mounts also replaced with the engine mounts?

 

[bonbon]

No - the transmission mounts were replaced last week to try and fix the problem. They were FEBI and it did not make a difference to the vibration.

 

[FLZ_Boy]

Check the harmonic balancer for any seperation?

 

[bonbon]

Looks ok and vibration disappears when driving at higher RPM.

 

[FLZ_Boy]

Has your idle air control valve been cleaned recently?

 

[bonbon]

ICV cleaned recently. My next step is getting 4 OEM mounts (Corteco)

 

[FLZ_Boy]

I looked back on the engine mounts and transmission mounts (5-Speed Manual) I changed out 200 miles ago, I did use Corteco. Comparing to the old OEM mounts I had (71,000 miles and 27 years old), I did notice a subtle more vibrations. It's more described as a feeling that you expected from new mounts, than it's an engine problem. Hope that helps on expectations.