407 very intermittent surging

[moizeau]

Thanks Marc, I was going to the oil counter sub-menu too early, found and done it correctly now. I had done the re-write bit, but it wouldn't let me set it 0, so I set it to 1. Thanks again, it's now set to zero.
Can anyone remember what their counters were reading when the oil change was done, and how many miles it related to? Thanks

[EDC5]

Glad you reset it. I never really considered the gearbox oi lto be a repalcement part... but it sort of is and it does make sense for it to appear in the 'pack repair' sub menu.

I'll dig out the pic of my oil wear counter, I've got it somewhere:

300,580. That's at around 58,000 miles

[moizeau]

Thanks, I must have misread my counter, yours is 5.2 x miles and mine reads 15 x miles, was trying to confirm or not whether the change today was it's first, but if I've misread the counter that idea is up the spout. Unless the counter isn't linear with the mileage? Need more examples I suppose. I think it was though.
Cheers

[EDC5]

It's not to do with the miles alone. It's based on the temperature of the oil and the time spent at that temperature. There may be a milage component to the counter value but it's not the only factor by a long shot.

[GiveMeABreak]

Yes that's correct Elis - I think I posted about it somewhere in the depths of the Forum - but can't recall now, but certainly the time spent at certain temperatures all affect the increments of the counter.

[moizeau]

Thanks both, possibly it's true then, the car has spent the last 100000m on the motorway prior to me.
The Forum is a mind of knowledge and very much appreciated.

[moizeau]

Elis, as that is true , surely oil changes should be referenced to the oil counter and not miles?

[GiveMeABreak]

The 'sealed for life' statement is a myth - but there are certain fault codes that will trigger if the counter reaches a certain value - but to answer your question oil changes on the AM6 and other Autos are really essential for longevity and performance, so should really be specified on a service schedule I think most will agree.

[EDC5]

Elis, as that is true , surely oil changes should be referenced to the oil counter and not miles?

I agree, however manufacturers that do recommend a transmission oil change have to guess what typical usage is and recommend an appropriate mileage as all of their other service intervals are quoted as either a time or a mileage and not 'usage'.

The 'sealed for life' statement is a myth - but there are certain fault codes that will trigger if the counter reaches a certain value - but to answer your question oil changes on the AM6 and other Autos are really essential for longevity and performance, so should really be specified on a service schedule I think most will agree.

I'm not sure how knackered the gearbox oil actually has to be before the counter triggers a warning light I think they set the threshold an order of magnitude too high to be useful.

It's interesting comparing our oil counter values. From my reckoning my oil was already badly burned at 300580 oil counter (58k miles), was yours like water at the much higher value? Any metallic specs in the oil at all? Any bad odours from the oil?

[GiveMeABreak]

Yes, from the looks of things, AM6 owners need to change their oil more frequently than the dreaded 1.6 HDi DV6 engines with the blown turbos!

[moizeau]

No specs of metal as far as I could see, I have seen thicker water!
Just been to see a classic car show (photos to turn up on POTD) and was checking fuel figures, seems better but I'll have to do more miles to get an accurate figure, and I noticed that it changes gear earlier. Remarked to my self how smooth it feels......then it had a surge! Not regular and if booted it took off but when easing off revs drop to 800. It's like the accelerator becomes a switch? I've looked in Diag to try and find where the potentiometer measurements are but can't, any ideas? Whilst I was in there I did notice that the soot was at 77%. Would this be normal?
Cheers

[EDC5]

No specs of metal as far as I could see, I have seen thicker water!
Just been to see a classic car show (photos to turn up on POTD) and was checking fuel figures, seems better but I'll have to do more miles to get an accurate figure, and I noticed that it changes gear earlier. Remarked to my self how smooth it feels......then it had a surge! Not regular and if booted it took off but when easing off revs drop to 800. It's like the accelerator becomes a switch? I've looked in Diag to try and find where the potentiometer measurements are but can't, any ideas? Whilst I was in there I did notice that the soot was at 77%. Would this be normal?
Cheers

So your old ATF was very thin then? likely it's heavily degraded and changing it will be very good for the box.

The gear change points will have probably changed as a result of resetting the oil wear counter. I believe the gearbox automatically de-tunes itself electronically when it knows the fluid it's working with isn't up to the job.

at 77% soot the FAP will most probably attempt a regeneration the next journey you take, try to make it a long one with some fast roads if possible


Regarding the surging, the old degraded oil may have lead to your lock up clutch wearing and it may not have much grip left these days. When you floor it the gearbox may attempt to lock up, fail, then just allow the torque converter to transmit the power leading to the high engine rpm whilst the gearbox side catches up.

[white exec]

Might very thin fluid simply be a bit on the leaky side internally, allowing some operating pressures to drop?
Might also have lost some of its friction characteristics??

[moizeau]

Chris, there's still a bit of the old stuff in there but I did a double change yesterday (7 litres). Just thinking back to the first 2 times it played up, it smelt hot and the second time when I opened the bonnet there was 'smoke' rising back the back of the engine. I was told the eolys fluid was refilled last year and after seeing the soot data and the fact that the regen status is regeneration I'm wondering if this could be connected, though I may be completely up the wrong tree as I'm still getting my head round these computer driven cars. I would have included the other 2 screen shots but the sun got them! I take it this car hasn't got a particulate filter ECU because it shows as not present. Are there any other screen shots that may be useful to someone with more of a clue than me? In 3 weeks the car has got to get me to Lyon and back, then shortly after, Wales. Not filling me with confidence. The fault does clear itself but without knowing why....
Thanks

[EDC5]

I can't quite read those pics, a bit low-res unfortunately. If you like I can take some to compare but the important bit is that after a regeneration, the soot level in the filter value drops significantly. This is calculated from the differential pressure sensor surrounding the DPF.

Might very thin fluid simply be a bit on the leaky side internally, allowing some operating pressures to drop?
Might also have lost some of its friction characteristics??

Good point, the old fluid might have been too thin for the AM6's oil pump to create sufficient pressure to operate the various clutches within the gearbox.