Diesel Particulate Warning light

[Barnsley John]

Anybody that’s read my previous posts will know I have recently fitted a 2^nd hand engine which came out of a 65-plate Outback.  My car’s been great over the last week apart from the central locking/alarm issues which I’ve posted.

At the beginning of this week, the Diesel Particulate warning light came on and I checked the hand book and followed the instructions and the light went off, this happened a 2^nd time and once again the light went off.  Now the light has come on and is flashing and the hand book advises I contact a Subaru dealer.

Does anybody have and thoughts on this?

[david1972]

sounds like it's clogged - can't you take it for a real blast at high revs for 20 mins?

[Barnsley John]

Already done that, 70mph up and down the M180 in 4th gear without going into 5th or 6th but the problem still remains

[david1972]

Not sounding good then...sounds like it will need dealer intervention @ £££s. Just hope it's not beyond retrieval, otherwise could get pricey.

Are you still under warranty?

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[Mr B]

Out of interest what injectors and ecu you using on your v5 ee20 transplant as wondering if cross parts of v4-v5 causing the issue, injectors different sizing etc.

Dpf (basically a soot trap) is a pita and ruins modern diesels . Hot water and pressure washing can be good and cheap way of reviving heavily clogged dpf, regeneration not good when heavily blocked as regen fueling is killing engine oil and creates huge amount of heat stress too, chemical cleaning systems on running engine do work but costly and don't always resolve that long before warning light on again .

 

[Barnsley John]

No everything been transplanted from my old engine to the new engine except for the fuel pump itself

[awebb320]

could be injectors overfuelling and not burning it off properly, there for clogging the dpf.  could be ecu updates need doing, have you suffered anypower loss and the hose going to the intercooler can split allowing to much air in and regen process can be completed

[Mr B]

Is it steady light or flashing light.

Could be worth looking at ecu firmware update status as mentioned, physically checking dpf would be good too, cleaning it out and seeing how goes could be way to start resolve, also temporary bypass to visually view soot at normal driving can be useful. early injectors can be problem and cause too much soot. Dpf is a PITA, I hate the things ...

[Barnsley John]

It’s a flashing light, initially it was a steady light and I followed the instructions in the hand book and it went out, this happened on 2 occasions but now the light is flashing permanently.

[Mr B]

Flashing is warning mode it requires forced regen .

If stays in flashing mode too long it will go into limp home mode with lower power

You want use something like  freessm software & vag obd-usb to read ecu date/codes on the dpf .

I recently purchased ssm3-4 diagnostics & training so better equipped for diesel issues (we getting quite few as dealers silly money & no complete cures, fair few on 2nd 3rd owner and they not happy with potential £300-£1,000 bill in first 6 months of ownership)

At moment we can reset & gain normal dpf function but soot levels & regens can be fast in reoccurring, besides obvious sensor/injector/dpf/driving style faults other issues with firmware & hardware are yet to have suitable solutions, hopefully modded diesel roms or more knowledge on hardware issues will help better resolve in time ....

[stants]

If your still having problems John, Martin at Sheffield subaru services isn't too far away may be worth popping it down to him

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[Barnsley John]

Yes Stants he’s been recommended to me before so once I’ve explored all the avenues open to me I might just get in touch with him… Thanks

Yes Mr B I’ve ordered an OBD reader that bluetooths to my phone software, it comes recommended but I must admit modern day motor systems have left me behind… I just drive a tanker these days

[Barnsley John]

Where is the DPF anyway… Where do I need to look to clean it out please?

[Mr B]

DPF is the big box with sensors & small pipes in exhaust right at front of engine below pulleys.
Do check pipes for pressure difference sensor all serviceable, not damaged, kinked, blocked ...
We use a bore camera to get good look at both ends of the inner filter & rough idea of build up
Pressure cleaning is last option on what appears heavily blocked DPF, good thing with pressure wash clean is can reverse flow & that gets lot of ash/soot out, can damage cat/dpf combo's if not careful plus ideally want be dried out prior to refitting .
First step is seeing your soot levels & oil dilution levels & get things reset & possibly a forced regen (due to flashing dpf light) & see how goes.
Using a dpf additive in fuel 3 times a year could be good practice too, Part of subaru service practice is additive in workshop & supplying bottle of fuel addative for use by owner at suggested interval .
You would need good software to have forced regen, oil reset, new dpf & programming function for injector change etc .You will probably be using or want try torquePro for android phone which should give access to some useful data values .


To be honest dpf in general is a problem in long term use & rather a waste really as you still produce the particulates but just waste a huge amount of manufacture parts (which have pollution value) to catch the soot which reduces efficiency (your performance & mpg is hit hard by dpf restriction in exhaust), then you waste even more fuel to spit this soot out on a regen cycle on a clear road !
Logically it counter productive much like most emission hardware. Pre dpf diesel are far far better & a modern tech diesel without dpf but with maximum design on fuel efficiency & clean burn, low manufacture pollution & long life cycle of all parts would be way better for environment :-/

[Barnsley John]

Hi Mr B, thanks for your help.  I took a look at the CAT/DPF combination which was transplanted from my old engine to the new engine.  I never had any trouble with the DPF warning light before neither steady or flashing.  The only thing I have not transplanted from the old engine to the new one is the fuel pump and I’m wondering if there could be any upgrades done in the new pump making it incompatible with my injectors?  I’ve used a OBD2 fault reader and it’s not showing any faults logged in the ECU.

I’m thinking of changing the fuel pump over this coming weekend before I get a forced regen done and are there any foreseeable problems changing the fuel pump?

My fuel economy is down over the last 500 miles by around 6mpg and whilst the car will pick up and pull away in the higher rev range the performance in the lower revs seems a little down to me.

I’d welcome your comments and yes I agree with your comments about the DPF being counter productive,

John.

[Mr B]

I'm not sure if there is any difference with the pumps, the scv (suction control valve) on the pump controls the rail pressure through pulsed control from ecu so any requirement on line pressure changes could of been implemented without massive pump redesign needed .

Worth looking at numbers on pump & svc and doing some research, Nozzles on the newer engine injector were different but I thought pump unit was compatible but i'm not sure as we all still learning on the EE20 and just not done enough big jobs on them yet so lacking experience & knowledge for yes/no answers.

Your power could feel down as if warning light stays on solid it will run in a lower power safe map, also if dpf well clogged it will itself hold back power.

Could be coincidence and dpf was close to issue prior to engine failure, could also pay a part in failure to to additional stress through exhaust back pressure.
Changing pump looks bit of pain but might be best way forward over always having a doubt .