Technical DPF regen Problems

[stuart543]

I was just congratulating myself on not having had any car related woes for a few months, but I've now noticed that my Croma (55 reg 1.9 16v Presigio auto) seems to be attempting very frequent DPF regen. I've noticed it regenerating quite frequently over the years I've owned so I'm familiar with the symptoms (drastic drop in consumption, burning smell etc) and it seemed to do a fairly major one a couple of weeks ago, but now it seems to go into regen mode every time the car is stationary for more than about a minute when the engine is running and its up to temperature (e.g. when stopped at traffic lights). This has happened several times in the last week (and I only do a few miles a day). I read on another thread that something similar happened due to a hole in the exhaust forcing out the hot gases so the filter remained clogged. However, my exhaust doesn't seem to be broken (e.g. no excessive noise). I guess I will need to get it looked at but wondered if anyone here might be able to give me an idea as to possible causes.

Thanks

 

[dave]

sounds like mine https://www.fiatforum.com/croma-ii/308653-dpf-clogged-regen-failed-maybe.html

do a forced regen before it gets to clogged to do one

 

[Doofer]

I didn't get any extra noise when my exhaust flexi had gone. You can look at it with a torch - you will see a sooty coating on the metal braid if it's split. This is all the garage did to check mine (much easier for them, with the car on a ramp).

If you can smell the regen then I'd say it's highly likely the flexi has gone. I never smell mine now it's fixed.

It's possible it's not doing a regen but what you're smelling is just the normal exhaust fumes. The best way to tell is to coast without accelerating and check the instantaneous mpg. If it's less than 99.9 then it's doing a regen.

Otherwise you can hook up a computer and check or force it, but the exhaust is the place to start.

 

[stuart543]

I didn't get any extra noise when my exhaust flexi had gone. You can look at it with a torch - you will see a sooty coating on the metal braid if it's split. This is all the garage did to check mine (much easier for them, with the car on a ramp.

Thanks Doofer - you were absolutely spot on. I had a good look underneath with a torch and the exhaust flexi was almost black. Got the wife to start the car up whilst I lay down beside it and on start-up a massive cloud of dirty smoke came out from the flexi pipe so that is clearly the problem. It may be that there is DPF regen problem as a side effect of this but I'll be able to get that sorted once the exhaust is fixed.

 

[buster]

Fiat ecuscan.Do a forced regen before changing the engine oil.I do mine twice a year.

 

[Hellcat]

Thanks Doofer - you were absolutely spot on. I had a good look underneath with a torch and the exhaust flexi was almost black. Got the wife to start the car up whilst I lay down beside it and on start-up a massive cloud of dirty smoke came out from the flexi pipe so that is clearly the problem. It may be that there is DPF regen problem as a side effect of this but I'll be able to get that sorted once the exhaust is fixed.

So glad that you spotted that thread. Get that flexi fixed or replaced ASAP before the turbo gets cooked through constant regenerations!

 

[stuart543]

Thanks for all of the advice - got my front pipe including the flexi section replaced this morning. I took it to my trusty local independent and they were able to source the part and replace it within a couple of hours for only £127 inc VAT (parts & labour) which I thought was very impressive, especially in Inverness. I also finally bit the bullet and downloaded the paid version of multiecuscan, and my cable has just arrived so hopefully I'll now be able to find out what's been going on with my DPF and do a forced regen if necessary.

 

[Doofer]

I'd leave it to do its thing for a while, it will probably just sort itself out now it's capable of getting hot, if you leave it a while (and make a decent journey on some nice thrashy roads).

You can check the DPF status though, and see when it was last cooked and how long it took.

 

[stuart543]

I thought I would post an update as my experience maybe useful for others.

After connecting up multiecuscan shortly after my last post DPF clogging was 67% which increased to 77% over the next week or so. Did a small regen whilst driving in town which bought it down to 72% then finally managed a decent dual carriage run which had no effect. The first screenshot below was from 24th Sept when it was up to 81%.

Having already investigated various options on this and other forums, I decided to try one of the DPF regeneration fuel additives in the receding hope that it might avert stronger measures. They all claim to increase exhaust temp and reduce the temp at which the soot burns so that it should reduce clogging even under normal driving. I decided on Forte but it was a toss-up between this, JLM and Powermax which all had more than one credible positive review (Wynns also do one which is cheaper than the others and available OTC at Halfords). I added this to the tank on Tuesday (25th Sept) and filled up at the same time. On Thursday I got a chance to take it for a 30 mile dual carriageway/Aroad run and made sure I kept it well over 2000 rpm. During this drive I noticed a massive drop in consumption which went on for several minutes so I was hopeful that a decent regen had taken place.

Finally had a chance to take another reading on Friday 28th Sept (second screenshot) and I think the results speak for themselves. I was genuinely sceptical as to whether this would work, and there may possibly be undesirable side effects, but the car is now driving as well as ever with power and consumption fully restored. I’m a bit worried that I still have 3/4 tank of this stuff!

 

[dave]

i wouldnt worry about leaving Forte stuff in, it will probably keep things cleaner.

 

[Doofer]

It looks good, but you can't say that the car wouldn't have sorted itself out anyway. I'd theorise it was just waiting for a regen to be due, and it happened that the time was right the moment after you'd put the voodoo liquid in.

If you put 400ml in a full tank then it's at 0.6%. Unless it's radioactive that's not going to make any difference to any temperature.

It looks to me like it kept getting interrupted from regen'ing in the first picture, as the duration is really low.

Yes, I'm a cynic. Pleased your car's running well though, whatever the cause.

 

[Tubularowl]

I've got a fiat doblo 1.3 on an 07 plate with 70k on the clock. When I bought it the "change oil" and "engine failure" codes were on the dash display. The car drove in limp mode as well. A bit of reading on the Internet pointed at the dpf filter so the garage cleared the faults etc and I bought it. I've done about 3000 miles since and no problems. The oil looked really dirty so I decided to change it which I did. I then bought fiat ecuscan registered version and an ELM lead which I used to reset the oil counter. The DPF showed 104% blockage so I ran a forced cycle. After 15 mins the oil dropped from 100% to 97% and the filter blockage dropped to 86%. Made the mistake of running the cycle with the car in my garage which was very hot and noisy so if you do this then do it outside. My question is should I run the cycle again to get the DPF lower or wait a bit.

 

[s130]

Personally I would wait and see how it goes.

The reason I say this is that as you have found out the regen cycle created masses of heat and with the car stationary there is no airflow around and underneath the car so it is constantly sitting in its own caldron which can't be that good for the car.

 

[Most Easterly Pandas]

The reason I say this is that as you have found out the regen cycle created masses of heat and with the car stationary there is no airflow around and underneath the car so it is constantly sitting in its own caldron which can't be that good for the car.

Its been designed with this in mind, should be plenty of heat shields etc in place

 

[s130]

Its been designed with this in mind, should be plenty of heat shields etc in place

That is true but why push the car to the limits. Normal regenerations take place on the move with free flowing air and do allow for occasional stationary moments like in a traffic jam or stuck at lights. I don't believe for one minute the whole system was designed to cater for repeated stationary and still air regenerations which is why if you don't need to do a forced regeneration then don't do it.

 

[Tubularowl]

That is true but why push the car to the limits. Normal regenerations take place on the move with free flowing air and do allow for occasional stationary moments like in a traffic jam or stuck at lights. I don't believe for one minute the whole system was designed to cater for repeated stationary and still air regenerations which is why if you don't need to do a forced regeneration then don't do it.

Thanks everyone for your replies. Don't do it in a garage like I did. I didn't know what to expect and when I initiated the cycle the car went up to 2000rpm then after a pause went to 3500rpm and sat there for about 10 mins. There was quite a burning smell. I'm going to change the oil again in another 2000 miles so I'll check it then and might do another burn before I do. Then I'll do 6000 changes after that. Great being able to see what's going on with your car. Elm lead was £16 off eBay and the software was £43. Worked perfectly. Easy to reset the oil counter as well. Only thing that did appear strange was that the odometer on the car shows 69800 but the computer once connected shows 66400. Odd.

 

[Most Easterly Pandas]

Thanks everyone for your replies. Don't do it in a garage like I did. I didn't know what to expect and when I initiated the cycle the car went up to 2000rpm then after a pause went to 3500rpm and sat there for about 10 mins. There was quite a burning smell. I'm going to change the oil again in another 2000 miles so I'll check it then and might do another burn before I do. Then I'll do 6000 changes after that. Great being able to see what's going on with your car. Elm lead was £16 off eBay and the software was £43. Worked perfectly. Easy to reset the oil counter as well. Only thing that did appear strange was that the odometer on the car shows 69800 but the computer once connected shows 66400. Odd.

FES / MES normally only shows in km though. Wasn't last service mileage you were looking at was it?

 

[Tubularowl]

FES / MES normally only shows in km though. Wasn't last service mileage you were looking at was it?

Could have been last service. I'll check it next time I connect. You can change from Km to miles in settings

 

[s130]

It is not unkown for MultiECUScan to report different mileages to that on the dash or in another ECU/control unit.

It is a little while since I looked at these on my Croma and if I remember correctly the Engine ECU mileage was different to the dash as was the body computer.

I wouldn't be over concerned at different values unless they are wildly out. I've had my Croma from new/delivery (1st owner) and I have differences. Shame I didn't have FiatECUScan when I first got the car to check the values.

 

[Most Easterly Pandas]

It is not unkown for MultiECUScan to report different mileages to that on the dash or in another ECU/control unit.

It is a little while since I looked at these on my Croma and if I remember correctly the Engine ECU mileage was different to the dash as was the body computer.

I wouldn't be over concerned at different values unless they are wildly out. I've had my Croma from new/delivery (1st owner) and I have differences. Shame I didn't have FiatECUScan when I first got the car to check the values.

Has never been an issue on any of the vehicles I've used FES on (looking about a dozen now). Always matched for me. Shouldn't be any reason why they wouldn't match if everything is origional. Is this a documented fault that Yani is aware of on FES/MES forum?