Engine: D5: Limp mode after warm up, DPF regen and fuel filter changed

[Clan]

well hes done a lot but what about the amount of soot in the filter it can be read out in gramms . thats about the only thing left before the DPF becomes suspect . Very very rare you have to change one ... if its reading hardly any soot and the pressure is high then its permanantly blocked . The fact that he was able to regenerate it is good because if the soot gets over 90 gramms it wont let you regenerate it .

[Appletree]

He said he did the regeneration and then took it for a test drive and some soot did come out the back on the test drive.

Just had a chat with mike again and we were looking at what codes we had and when.

So when i fist got in the car yesterday i had the "engine system service required" took it for a 20min drive at an average of 50ish with no boost but no dash lights.

Came home left it on the drive for 15mins then started it to drive over to see mike, drove all the way over with no probs and got the codes

ECM
2A20 - live
2A50 - cleared
2A70 - cleared
6661 - cleared

we reset the codes and got the 2A20 code streight back up twice.
Dads car had the DPF software update with the lower oil level sticker not so long back. As this code is not effecting how the car runs ( its still up at the minute and running fine) could this be a Faulse code thats masked from the software update???

As the car is still drivng ok with the 2A20 code we think it might be a problem only when the car trys to do i DPF regeration which is why the car drove ok when volvo gave it back to us and after me and mike reset the codes.

Think i'm going to go for a spin in it again and see if i can make it do a regeneraton and if thats when it goes in to limp mode when the other 3 codes flash up.

Clan - would i be correct in saying that during a regeration the car runs with the Glowplugs turned on? or does it do something with the glowplugs?

Thanks Matt

[Clan]

The glowplugs dont have anything to do with regeneration , a small amount of extra fuel is injected after the power stroke to get the exhaust temperature up to about 600 C .

[Appletree]

Hi Matts Dad here thanks for all the help so far, just been for another drive showing engine system service required and in limp mode again.

Once we got 8 miles away and on to open roads coaxed revs up to 3.5k came off limp mode and pulled normally and stayed clear of limp untill dropped down to lower revs.

Could it be that the core of the DPF has burnt through and that there is no initial back pressure but that there is an increase in back pressure which satisfies the ECU at higher RPM.

The Volvo guy said after the DPF regen had been done that there had not actually been that much soot in it gram wise although there were some emmissions on the test drive.

Any ideas Guys? And if the worse comes to the worse anyone know how much a new DPF is?
Cheers Phil

[Clan]

there should never be ANY smoke out the back with a particle filter , perhaps the Particle filter is faulty .. only your technician can tell you that because he is there with everything in front of him .

[Appletree]

Have you heard of a DPF filter burning out/through like cats do on petrol cars? Just thinking , lots of regenerations may have burnt it out? think me and dad are going to take it off the car tomorrow and see what's what with the filter and the pipes.

I've managed to read the codes on the torque app on my HTC phone and the 2A20 code is always there and the car drives normally when its on and then goes in to limp mode and we get the "DPF efficiency low" code.

(this isn't a Volvo code as its through an APP but ties up with the codes we had before)

See what happens tomorrow when its on the floor.

[Bill_56]

Originally Posted by Clan

The glowplugs dont have anything to do with regeneration , a small amount of extra fuel is injected after the power stroke to get the exhaust temperature up to about 600 C .

With the greatest of respect Clan, are you sure of that?
See here:
http://www.volvoclub.org.uk/tech/New...006-Theory.pdf

During regeneration the glow plugs are activated with a small load for example. By increasing the engine's load the temperature of the exhaust gases also increases which is necessary to obtain a correct regeneration process.

That same document also suggests the throttle body is used during regeneration, which has also been disputed when mentioned on these forums.

Is the 'new cars 2006' document incorrect?

- Bill

[Appletree]

Hi Bill,

Thanks for the info, the reason i asked is because the tech who spoke to my dad said he new the new shape V70s did use the glow plugs in someway during a regeneration but he wasn't 100% if they did on my dads shape.

The reason i asked is as we got the "ECM-6661 glow plug relay fault" along with the others and we only seam to get the codes when the car tries to do a regeneration.

[Clan]

Good spotting , its 7 years since i read that document and to be honest glow plugs dont cause any problems in general , but always a first time of course . The code ECM 6661 indicates that there may be a problem with cylinder one glow plug .

The glow plugs are activated to put a load on the alternator and hence engine which helps with the combustion temperature , the purpose isnt actualy to heat up the incoming air as in a cold start below 5 C ..

The main problem here is the particle filter pressure sensor signal is lower than expected for what ever reason .
I'm going to have Wimorrison after me again

[Appletree]

So, me and dad have had a look at the car this morning and started off by putting it on the ramps and having a look underneath. The DPF looked fine on the outside, as you would expext, althoug while i was under there i noticed the was a pin hole in the weld of the back section near where it ataches to the DPF that was blowing very slightly and had a drip of water from it. The main thing i noticed though was that the to hangers for the streight section of the exhuast to the back box had snapped clean off from the pipe and were just hanging on the rubber mounts. Not trying be funny but surly if you was the tech changing the fuel filter you might have noticed a wangly dangly exhaust just next to your ear!

They were also kind enough to point out that one of the front tyres was close to being ready for changing and quoted for a new one but not an exhuast????

Back to the job in hand, i took the rubber pipes off the metal pipes on the DPF and visualy checked the rubber pipes for blockages and found non.

Next dad started the car with me laid under neath and streight away soopcame out of the large pipe at the front of the DPF, not loads and loads but enough that it could have been slightly block, also the jubilee clips holding the rubber pipes to the metal were only finger tight.

With the car running there was some pressure coming from the front pipe of the DPF but not from the back as you may expect. Next dad blocked the tail pipe with his had on and off to build some pressure and air under pressure came out both pipes with ease. We were happy both pipes were clear.

Next we decided to check the pipes to the DPF pressure sensor. They run up the side of the turbo to here

There in the back ground running from the bottom of the pic upwards in a metal clamp.



Next, strut brace off


Strut and cover removed


Unplug sensor plug


Remove the sensor with 2x small torx screws

They've circled the problem for us lol FORD


Again not to doubt the tech but it realy didnt look like anyone had been in the area we were working, not clean patches on the dirty bits and everything still tight, even the rubber pipes which just press on were "stuck" on like rubber gets when its been on for a good bit.

we again started the car and checked the pipes, no soot this time and again pressure from one at idle and not the other and then pressure from both with my had on the tail pipe and dad checking. so everything seams ok.

Finaly tryed to clear the fault codes with my Torque App as we dont have the VADIS kit yet but i not could clear them, any way took the car for a run again and no fault code or "engine system service required" it ran well and returned good MPG .

Were going to see if the problem comes back over the next few days and go from there