Euro4 D5 / 2.4D DPF or Sensor Issue ?

[graemedench]

OK

Having alot of trouble with my DPF however I'm really starting to think its really the sensor! Any pointers would be great I know Clan has previously said :-
The reading from the sensor with just the ignition on and engine off . ( should be zero)
The reading at idle (3 to 20 hpa depending how much soot in filter )
The reading when revved hard . ( may go up to 70 Hpa with soot in .)


I am seeing off 0Hpa
20 idle when cold quickly going beyond 100
then when revving hard and temperature 500+

I just don't believe it , I bought a new cheap sensor (big mistake) to check against however it gives fault ECM-2A00 Pressure Sensor Trap. Signal too High and will not read any variation in pressure.

Anybody got a feeling on it or seen similar issues ?

with the original sensor I get the following errors saying filter full, signal faulty. signal low. (I know I was an idiot and forgot to take a snapshot of the errors)

Would a blocked DPF show the kind of figures I'm seeing ? I've started taking the EGR apart to clean it out in the mean time and I kindly have the loan of a Mighty Yaris to get to work. I know I can get a Volvo sensor for £100 or I can take the dpf off and flush for £50,

I've never had a DPF problem in the 4 Years I've had this and my driving's not changed at all, Interestingly the sensor that's on the car looks like it may have been replaced at some point as it has numbers etched into it as if maybe a scrappy has put there identifier on it ?

If anyone has maybe values they've seen on a blocked dpf then it would give me a clue,

Sorry to those who have seen this posted (with slightly less info) on the Phase2 section, but maybe others have seen this problem.

I'm looking to sort this and then probably sell up cars been great apart from this really, Feeling the call for a Defender again

[5cilinder]

Whats the mileage and oilconsumption ?
Maybe its saturated with ASH instead of soot , and is there nothing wrong with the original sensor
You can clean the dpf of ash by force regenerate it to remove the soot first(wich blocks the ash) and than take the dpf of and vibrate it upside down and the ash comes out like sand , than some pressured air for almost the rest

[graemedench]

Hi

Thanks for the reply, 130,000 give or take. I've tried a forced regen but it cancels out about half way through. Oil consumption is pretty much undetectable. I have taken the dpf off and given it a blow out with the compressor and a shake nothing seems that bad, egr is sooty but nothing compared to some pics I've seen. I don't know if anyone's seen hpa values for a blocked dpf if what I'm seeing is relistic or not, it's why I'm leaning towards the sensor maybe, I'm making sure the egr is all cleaned up anyways while its in bits. I've tested all the cables to sensors and they are all fine too.

[5cilinder]

130000 with no oilconsumption shouldnt give problems ashwise when you took the dpf off after a forced regen , how much ash came out?

Did you check the tubing of the sensors on leaks /clogging or restrictions due to torsion/bending?

[graemedench]

Hi very very little ash if any, it was a bit sooty but really not that bad either, easily see all the small square holes etc. I do 2*20 miles a day at around the 70 mark along with 5 miles of country twisties at each end. I checked for blockages but I will double check for any leaks, Many thanks for your help. Looking at the pressure difference its looking at I guess it wouldn't take much for it to get upset. As I say its fine when its cold but as things heat up it gets dramatically worse. thinking about it if its left to idle for a while it does get better again ie the hpa value drops back and as I rev it again it builds back up. So i guess its either an imbalance in the sensor and its sticking or it really is a blockage. I know it can get the stuff to soak it overnight for around £50 and a genuine Volvo sensor around £100 or a cheap DPF for around £250 i think. Any of I could do, but I dont if possible want to end up doing all 3 unnecessarily on a car I'll probably sell for around £1200 - £1500 if I'm lucky

I'll check the lines as suggested thanks and report back probably tomorrow now.

[5cilinder]

You need to do the forced regen right before you take the dpf of , the soot blocks the ash
The sensor values you stated seems to be normal . and yes its sensitive

[graemedench]

I cant seem to get it to complete a forced regen it always seems to cancel. I'll check all the pipes etc, finish cleaning the egr and try get it to do one again. Reading between the lines sounds like your thoughts are it is the DPF vs sensor, Strange I would have expected more warnings before the soot filter full see manual message. Anyways I'll do all that and see how it goes and report back.

Your input is extremely appreciated

[5cilinder]

No i think the tubing/sensor is more suspect (i dont rule out dpf yet) . i was just curious of the amount of ash
If you force regen you can check with the check soot how much soot is left you can see it countdown in milligrams while regen ,only try to remove the ash while the soot is zero

Since you can do forced regens i suspect you have vida
You need to callibrate sensors there after replacing , did you do that?
Also logging sensordata while driving/regen is extremely valuable

btw: if a forced regen is cancelled or aborted it will automaticly try to finish it as a normal regen while driving

[graemedench]

Hi
Thanks so much for your constant input I definitely owe you ! I've just finished cleaning the EGR etc and got it back together so all spick and span.

I've checked the hoses etc from the dpf and they look good too.

Yes I have Vida. I will do another sensor re-calibration tomorrow before I start and clear all codes. Then try a forced regen and see how it goes. The car is pretty much un-driveable when it goes into limp with the soot filter full message. I will log as much and graph as much as I can while it is all running and let you know.

One test I was thinking might be worth doing is disconnecting the sensor and taking it for a drive ? If it really is as blocked as it thinks it is then it should be nearly as bad with the sensor disconnected ? Presumably it maybe assumes dpf is nearly full if it doesn't see the sensor at all?

I did take it for a drive previously with the rpm, DPF pressure and temperature graphing. it started out fine (sub 20 hpa) and as temperature increased in the dpf so did the pressure at Idle revs, till i was over 500 hpa.The dpf pressure increased in a parallel curve with rev's the whole time.

I can only give apologies as I know I'm dripping out bits of info that probably would have been really useful at the start, I'm doing exactly what I hate when people come to me with a problem at work sorry ( I work in IT)

I'm sure this is all the info I have now (until tomorrow)

[5cilinder]

Mmmm
Now i suspect the sensor is behaving well with a clogged dpf , all the symptomes you describe are pointing to this .500 is too much (if the before dpf sensor tube isnt leaking or the after sensor not clogged)
Your best bets are forced regens instead of driving regens because the drivingload will create extra backpressure due to extra exhaust flow
and check if soot is declining bit by bit
Did you check under the combusting particles vtc button how much soot the ecu thinks is in the dpf?