C4 mk2 revving issues

[K_gopsill]

Hi, i have a c4 mk2 1.6hdi and have issues with rough idling and struggling to rev over 3k. I have had error codes P1445 and p3007. I have changed the egr valve and have taken off the bottom part of the dpf and gave it a soak with off car dpf cleaner and power washed out, but still these errors persist and is still sluggish, what else could i look at? Thanks

[GiveMeABreak]

First of all when you cleaned the DPF, did you use a professional level diagnostic tool to tell the engine ECU that you have replaced the particle filter? If not it will still think the old one is there and still give the nag warning.

The engine ECU may be limiting power whilst these faults are active.

As for the P3007 fault:

Fault Code:	P3007
Description of Fault:	Air circuit: Air flow lower than recommended. Ratio of measured airflow over calculated theoretical airflow below -15 % detected for 2,5 seconds. Conditions of activation of the diagnostics: The following conditions have to be met: - Air temperature between -20°C and 100°C - Battery voltage between 10 and 16 V - Turbo pressure between 740 and 1500 mbars - Engine coolant temperature between 50 and 100 degrees C - Engine speed between 1400 and 3000 rpm - Engine speed variation less than 16000 rpm per second - Air mixer open - Exhaust gas recycling valve closed
Conditions for Fault to clear:	Driving for 5 minutes with decelerations of more than 10 seconds
Downgrade Modes whilst Fault is active:	-
Symptoms:	Jerking/stalling Noise Lack of power Starting problem Engine acceleration at wrong time Warning lamp MIL
Suspect Areas:	Atmospheric pressure sensor in the engine management ECU Air temperature sensor at the air flowmeter Air flow meter Air intake between the air flow sensor and the turbocharger Turbocharger Turbocharger fixed geometry control electrovalve Turbocharger fixed geometry position repeat sensor Manifold air entry pressure sensor Manifold entry air temperature sensor Exhaust gas recycling valve Engine oil Sump Oil suction strainer Engine oil pump Lubrication circuit of the turbocharger Electrical harnesses Connectors

[K_gopsill]

Cheers Marc, (i have 2 C4's and these fault are seperate to the other one) i have used my foxwell scanner to tell it has a new dpf, revving seems better, but stutters at 3k but does now go over 3k. Car is still sluggish, could it be blocked egr pipe at the back of the engine?

[GiveMeABreak]

I'd be checking the airflow meter and very carefully cleaning the sensor wire with some specific MAF cleaner.

If you have live data capabilities, look to check if the EGR valve is operating correctly - you should be able to test operation of this. On some vehicles you may also need to tell the engine ECU the EGR has been replaced.

There are lots of possibilities as you can see which could contribute to the cause of this, so hard to say, but getting some live data and checking the various sensors against any reference values may also help to check for correct operation af any sensors / systems.

[K_gopsill]

Quick update, so i used an on car dpf cleaner through the top sensor on the dpf, and the top of the dpf was clogged (the tube to squirt the cleaner in was covered in soot) followed the instructions and forced a regen through it and the car was running as it should, drove it to work and back and it was fine, and no error codes. I then went out last night, got stuck in traffic and it came back, sluggish revs, struggling to go over 3k revs again and error code p3007 again.

I think i'm on the right track, would a whole new dpf be my next route (not just the bottom part where it splits)?

[Paul-R]

An off-car reverse clean would be the next step really. I wouldn't have bothered with the on-car clean as it won't be as effective. It cannot clean anywhere near as well and off-car doesn't need a forced regent, just a drying out.

[K_gopsill]

Thanks for your reply, so take the whole dpf off, split it and power wash it from where it splits? I have already taken the bottom part off a couple of weeks ago and cleaned that bit.

Thanks

[Paul-R]

Not a power wash! This can destroy the delicate honeycomb structure of the dpf.

Use a proper acid dpf cleaner (there are links to YouTube videos on this in other posts) in reverse, leave to soak for whatever time is recommended and then back flush with a gentle flush through with plain water.

If there's a lot of oily residue in there then it should be cleaned out first with an alkaline wash.

The acid used is hydrochloric acid. This can be bought from builders' merchants in the UK as brick cleaner but needs diluting down.

[Paul-R]

Don't forget to reset the (engine?) ecu to reflect that a 'new' dpf has been fitted.

[K_gopsill]

Cheers Paul-R, for your help, dpf is coming off tonight, need to get it sorted once and for all!! Thanks

[Paul-R]

Have a watch of this video. Not sure about his sense of humour but the technical content is excellent.



And him again. It's on a BMW but the techicals are the same

[K_gopsill]

Had a watch, thanks, even though i have the wynns off car dpf cleaner, i'm going to go down the hydrochloric acid route, do all brick cleaning acids have this, as i have a screwfix round the corner from me and they have some but doesn't state the ingredients!

[K_gopsill]

Hi, so took the dpf off and soacked it in brick cleaner and rinsed to through with a hose, it's clear, could see daylight through it. Put it all back together, told the ecu it has a new dpf, and was running fine, took it for a blast, and revs smothly, then all of a sudden, it lost power, wouldn't go over 3000 revs (presume this is limp mode). Scanned it and error code p3007 appears again, deleted the fault, car runs fine for a bit and then back to limp mode. Could this be the EGR valve being a bit sticky? Thanks

[K_gopsill]

So another update, car is really annoying me now, driving home today, aswell as the above issue, particle filter at risk of clogging popped up, how, i've cleaned it, should be empty or is the egr valve sending a bad signal to flag up the dpf if the egr turns out to be faulty?

[GiveMeABreak]

You may have cleaned the DPF, but unless you have a diagnostic tool like Lexia / Diagbox and told the engine ECU you have replaced the DPF, then this won't make a bit of difference, as it has no way to know you have done this.