I've done about 270km in the week since updating. The noticeable abnormal clatter noise has not
I should clarify that there is always some injector noise which varies with revs/engine load etc. This is normal as it's a diesel engine, not a Nissan Leaf electric and the fuel is pressurised to something like 2000bar so it's not going to be completely silent. There is always going to be a "tak, tak, tak, tak" noise which is going to be most audible when the revs are low and when your foot is on the load pedal.
To hear it clearly and distinctly you have to drive with the window open and listen for it.
The abnormal noise I had was a very noticeable loose clatter "K-LAK, K-LAK, K-LAK, K-LAK, " when at low revs and high load when the fuel is injected at higher flow. I could hear it clearly with windows up or down.
As soon as the service guys applied the RRT 14-104 (18-019-14A) PCM update, that type of noise was instantly gone.
Normally running the VM engine is certainly quieter than any new 4 cyl or 5cyl 4WD diesel from Hilux, Ranger, Pajero, Colorado etc.
I test drove all of these before buying the JGC.
Ok there are some smoother like the new 3.0TT in the Landrover and the 4.5V8 in the Cruiser and 4.2V8 Audi but maybe that's the exhaust grumble masking the other noises.
The noisiest new diesel 4WD is probably the Colorado 2.8 there is a significant noticable injector clatter in normal running in that truck.
The 3.0L Nissan Patrol is pretty bad too.
The abnormal Diesel clatter I had in the Jeep was probably only slightly louder but more "loose" sounding than any of the 4cyls. Certainly it's pretty annoying.
When off the pedal (minimal fuel injection) there is no injector noise at all of course.
Hope that helps to describe what (I think) is the normal and abnormal condition.
On a side note: Because I'm an Engineer (groan
) I had been doing a bit of reading about Diesel injectors in modern engines prior to buying this, my first diesel. These things are pretty complicated and a lot has been done to comply with emissions ratings and generally to improve the smoothness of engines in the last 10years or so. Fascinating stuff.
The VM engine has some sort of D-IRS (digital Injection Rate Shaping) developed by Fiat. There appears to be a fine line in the balance between soot production, NOx, combustion noise, power output, economy and of course variations in the fuels.
It's all in controlled in the software and it looks like they are still in the debugging phase.
I feel a bit like a beta tester, but that is becoming the norm these days with all of our various and increasingly complicated electronic devices.