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2016 Forester Diesel
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Discussion Starter · #1 ·
This 2016 Forester just keeps on giving!!! I leave the garage door open in the hope someone will steal it..
This problem has been driving me crazy .
I have just installed an EE20ZV engine that has done 100K Kms. Came complete with loom etc so it was plug and play.
The previous DPF was reinstalled. IT IS CLEAN & FREE FLOWING. Two Differential Pressure Sensors test ok.
But when I took it for a drive the DPF light came on, then limp mode. Back to base.

I used a scanner and reduced the soot level from 210% down to 7%. Test drive and I am in limp mode again.

Use scanner to 'New DPF Installed' which drops the data level of ash and soot to 0.
Started the engine and watched live data.
While idling the soot level stays at 7% (all day !!!!) but as soon as I touch the accelerator the soot level rises. Back off to idle and it will stay at what ever level it has reached ( say 35%).
Eventually, Im in a cloud of smoke as the ECU attempts a regen.

With engine running at 2000 rpm the soot level will reach 100% in about 100 seconds

The EGR seems too active ( especially on a cold motor) so I have disconnected the MAF/ Air Temp sensor and that seems to have stopped EGR and the phantom soot. But why?
About that stage my brain stopped working. Any bright sparks out there?
 

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2010 Forester Diesel 6MT
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896 Posts
Assuming you've installed the correct engine for the car & ECU (there are likely running changes year to year if not month to month and country to country)...

Did you relearn the new engine to the old ECU? A new 'drop in' engine means all new actuators, motors, pumps and valves, etc. for the current ECU. Especially the fuel injectors I'd suspect, but also the throttle valve, EGR valve, fuel pump/rail, turbo actuator, cam position/actuators, etc etc. Find out what you can relearn/reset and do it all. There may be a procedure/program in your scan tool, and there will likely be a particular order to do things in. I'd suggest the injectors are particularly important. I think you need to read the codes off them and program them into the ECU.

Other issues/suggestions:
  • is the MAF reading correctly? You may wish to try cleaning it- use MAF cleaner only (no carby cleaner, etc).
  • what is the DPF differential pressure reading? When mine registers several kPa soot climbs very quickly.
  • hopefully you don't have something like a turbo oil leak causing contamination of the DPF.

Also, (all refers to my older 2010 ) EGR is used when cold to help warm the engine up (does on my older car). You may also find the throttle closing when cold in cold weather at low throttle settings. Under these conditions, it seems the car is not in 'closed loop' and runs on MAP rather than MAF. If you have turbo leaks then it tends to run properly when cold as it reads from the MAP which is affected by the turbo leak and reads correctly whereas the MAF is before any turbo leak and therefore registers the airflow including any leaked air, leading to rich running (and soot) .
 

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2010 Forester Diesel 6sp Manual
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182 Posts
A new 'drop in' engine means all new actuators, motors, pumps and valves, etc. for the current ECU
This is very correct. They all need to be "learned" or calibrated to your ECU.

Also, what is your backpressure when soot climbs? Also air mass (mass not flow) on idle and on some rpm's.
 

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2016 Forester Diesel
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Discussion Starter · #4 ·
Hi guys thanks for the replies; to cover some of your points.
DForry, Original code was P2453. Now no codes. NO back pressure ever! The Soot is just a phantom, it does NOT exist.
MAF is cleaned , it is the original unit, Differential pressure sensor signal 1.2V .
Total run time 35 seconds:
@ 801 rpm MAF 5.7 g/s .
EGR 5% duty , 42 degree opening angle.
Soot 7%
@2200 rpm MAF 48 g/s
EGR 25% duty , -2 degree opening angle.
Soot 76%

I will run some more live data today.

Pitrack, I have gone through relearn, most functions seem to cooperate, except for EGR. Scanner will not allow me to address that, nor can I write the the new injector codes. In the past, Ive found that a relearn leads to smoother and more efficient performance, not something this critical which appears to lie deeper in the ECU.
The injector code failure is due to the new Launch scanner not being up to date with Subi files. Mr Wong said update is due this month.
Now it may be easy to say, well thats your problem, but the soot rise of 0% to 80% after driving just 200 meters , is exceptional. No one at this end has an answer.
The air / EGR loop seems??? to be the problem ??????

My mind goes back to the scumbag dealer. His mechanic's note to the past owner was still in the glovebox:
"P0401 EGR abnormal (Egr amount too small) Safe to drive."
Curious as it seems, I could only assume that it was an excuse for the mystery camshaft rattle, in the hope the owner would disappear and put up with it for ever.
Given that low EGR can cause engine rattle, Im now wondering if they tried to tamper with the EGR duty in an attempt to quiet the knocking.
 

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2010 Forester Diesel 6sp Manual
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So, your differential pressure sensor reads 0kpa all the time?
Even at 0 soot (no actual soot in the dpf) there must be some back pressure.
Something is really wrong here.
 

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2016 Forester Diesel
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Discussion Starter · #6 ·
For those who are not aware of this Foresters history : ('14-'18) - 2016 - Two Dead Motors - Updated!
I have bench tested the diff sensor that came with vehicle and the one with the new engine.. Both test ok. I suspect that this phantom soot level was occuring when the Forester arrived here. It did a regen as I left to take it back to the dealer and possibly on the way back. But no warning light or limp mode, round trip was about 100km.
 

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2016 Forester Diesel
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Discussion Starter · #7 ·
So, your differential pressure sensor reads 0kpa all the time?
Even at 0 soot (no actual soot in the dpf) there must be some back pressure.
Something is really wrong here.
DPF deviation = 17.54 Kpa
 

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2010 Forester Diesel 6sp Manual
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DPF deviation = 17.54 Kpa
Well, there is your problem.

0-3kpa on idle is acceptable by service manual. Mine was flushed recently and now fluctuates between 0 and 1kpa on idle. Going 100kmh it is somewhere 4-6kpa. On heavy acceleration it jumps up to ~13kpa, but 17.54 is insanely much.

To be 100% sure it is dpf, try this: Disconnect pressure hoses from sensor and see what ECU reads. If it is 0, you're all good on sensor/ECU. And you should check backpressure with an analog gauge, but it must be sensitive enough to give accurate readings, because 17kpa is 0.17 bar or 2.5psi.
There may be structural damage inside the DPF, or it has been flooded and damaged with oil or fuel.
This may give you some information.
 

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2016 Forester Diesel
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Discussion Starter · #10 ·
So, your differential pressure sensor reads 0kpa all the time?
Even at 0 soot (no actual soot in the dpf) there must be some back pressure.
Something is really wrong here.
looking better, explain later, thanks.
 
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