C8 2.2HDi really hates hills - turbo or DPF issue perhaps?

[tearing hair out]

Hi - I'm new here, though I've lurked a bit in the past.

I'm having some issue with my 2004 C8 2.2HDi at the moment and I'm really struggling to resolve it. Recently, it's been feeling a bit sluggish in general, but it really doesn't like hills - ones it used to be perfectly happy to accelerate up in 3rd, it now struggles up in 2nd. Worse, if I have to stop on the hill, it's really hard to get moving again. Living in Wales, climbing hills is quite important.

It doesn't seem to be that it's tripping into limp mode - it's always sluggish and I haven't seen an engine management light.

Reading the faults, I have the dreaded particulate filter. The garage topped up the fluid (added 1L rather than filled) and I think they reset it - it's showing 180g used since last reset. But these errors remain and won't clear (I'm not getting any warnings about the fluid being low on the in-car display):

The fuel cap presence sensor warning has been there since I got the car 4 years ago - I think that's integral with the Eolys tank and I can't fix it without replacing the tank? Though, perhaps, at this point I need replace the tank anyway. (EDIT: Actually, I think that must be nonsense. Though I've apparently managed 40,000 miles with it not working - not sure what the history was before that.)

Are these DPF codes something that could be triggering a permanent (and unindicated) limp mode?

(I'm assuming the pre-post heater warning is glowplugs and I can safely ignore that if I'm not having cold start issues?)

I was also wondering it if might be a turbo issue - no boost under load or something. The garage reported some oil in the area of the turbo, so I wouldn't be entirely surprised if there's a seal issue after 150,000 miles. Here's a video of the turbo-related parameters from Lexia, while trying to accelerate up a hill in 2nd and 3rd. Just numbers, since I don't seem to be able to get Lexia to make graphs of the data. As far as I can see, the target and actual turbo pressure is pretty similar, but I have no feel for what the numbers should be - maybe someone will see something that stands out?


I've also seen mention of problems with vacuum leaks affecting the turbo - is that something I should be investigating here?

Many thanks for anything that springs to mind!
Paul

[GiveMeABreak]

I'd actually need the fault codes and your VIN Paul. They're not shown in the above, but initial observations:

The Fuel filler cap detect (where fitted) is only used to determine if fuel may of been added.
The weight in grammes (180) refers to the amount of additive - more specifically the amount of Cerine which is a compound in the additive which can't be burned off during regeneration. It is this compound, along with engine deposits and other debris that lead to the clogging of the particle filter. The engine ECU or the Additive Control ECU records the amount of Eolys fluid that has been added to the fuel tank over time and when the estimation of these compounds hits the higher levels (in weight), it assumes the filter is at end of life and needs replacing.

So as far as the filter goes, removing and cleaning it out (I'd use a specialist service to do this) may prolong the life of the filter, - BUT - the engine ECU must be told that the particle filter has been changed - otherwise it will have no idea and keep thinking the original filter is still in place and is end of life. This must be done if cleaning the DPF as well as if / when it is replaced.

You don't appear to have any warnings on the dash regarding DPF clogging based on data from the differential pressure sensors (which are really only used for safety reasons to monitor pressure), so it may be the filter is still working. But it may also be the case that the filter is starting to become restricted given the mileage - which is over the recommended service life. Any issues with blocking can also lead to back pressure - which could impact on performance.

So as we know for certain your filter has done the miles and is probably due for a deep clean or replacement, I would focus there to start with.

[Rp0thejester]

Welcome fellow C8 driver, I have similar issues and I used to plan routes to stay away from hills. Now I'm confronting it head on!!! With my eyes closed and a following wind down hill. Please keep us posted on your progress

[Rp0thejester]

I've just used a can of Wynn's EGR Cleaner on my C8 with the help from my 13yr old. I'm hoping that will help with the uphill climbs, I'll let you know tomorrow.... fingers crossed

[myglaren]

Get your 13 year old to get out and push it up the hills, that should help a lot and keep the fuel costs down. Good exercise too!

[Rp0thejester]

That would only work if I dangled his mobile phone in front of him, like a carrot in front of a donkey. Even then he'd give up, but sitting in the driver's seat revving a car, he's more than happy to help. Yes, he likes sitting down

[tearing hair out]

Thanks Marc. I'm trying to find some time to go out with the Lexia again to see if I can find the raw fault codes - and probably check the pressure drop across the DPF for good measure, since I should have checked that before. Hopefully in the next day or two.

Ryan - I hope you EGR cleaning does the trick! Sounds a lot cheaper than a replacement DPF.

[Rp0thejester]

Well did the cleaner, took her for a run, no difference in performance but the coolant low warning has finally gone, so a result. I'm now gunna look at that swirly thingy majic to see if that's the issue.

[Rp0thejester]

It might be worth a look for yourself, it's under 'Very strange bolt'. It might explain the symptoms your having, same as me

[tearing hair out]

Finally managed to go out with the Lexia again.

The VIN number is VF7**************[VIN obfuscated, can be read by forum staff]

The fault codes I have are:
P1521 - Clutch Switch signal
P0380 - Pre-post heating relay circuit
P1442 - Amount of additive (Fuel additive ECU)
P1442 (same code?) - Amount of additive (Max additive level in particulate filter reached)
P1435 - Fuel additive system (Fault: fuel filler cap presence sensor)

I also went for a run up my favourite hill - 30MPH in 2nd and 3rd.


The pressure across the DPF peaks at 65 millibars, but I don't have a feel for what it should be. It doesn't feel all that high to me, particularly since the sensor (or maybe Lexia's reading of it from the ECU) seems to move in 5.9mbar steps - suggesting it's expecting the number could get quite big.

[tearing hair out]

It might be worth a look for yourself, it's under 'Very strange bolt'. It might explain the symptoms your having, same as me

Ah-ha! I hadn't realised that's where the EGR valve lives - it looks almost accessible! I think I've seen a few references to faults with the swirl value and vacuum leaks - I'll take a look in the daylight tomorrow - thanks.

[tearing hair out]

I had a look and I can't see any obviously damaged / disconnected vacuum lines, and I couldn't hear anything leaking just after turning off the engine. I guess if the swirl valve diaphragm is destroyed, there could be a big vacuum leak, though presumably none of the vacuum-driven valve would work in that case.

I guess a stuck-closed swirl valve might give me a loss of power? Presumably you haven't tried doing much with it yet, since the post is only recent?

[Rp0thejester]

I've not had a close look at it yet, my heart is saying do it but my ginger headed brain is saying don't be so stupid, you'll burn in this heat

[tearing hair out]

I used to do a lot of the work on my cars, but I'm long past that - most of it gets left to my local garage now-a-days.

[tearing hair out]

Right. Swirl valve actuator. It retracts at idle and extends when the engine is revved, so I think I don't have a vacuum leak or a dead diaphragm. The arm is, however, not connected to the ball on the swirl valve lever, but it seems to be tending to stay down - which I think would be open. So, I don't think that's the source of my problems.

So my current guess would be a blocked DPF or a gummed up / stuck EGR valve.

When the engine is cold, I'll see if the swirl value actuator will reconnect to the lever - I suspect not reliably.