Technical dpf blocking

[Telegraph]

Hello just had some drama when em light came on,I plugged in fiat ecu scan and dpf blocked !. Having not had any trouble in five years I was a little shocked and did a forced regen, after five min and a patch of melted tarmac on the road all done and no em light but the ecu scan says that it is still 80% blocked and yet says blocking is usual. Still not sure if it will need a new dpf.
Advice would be very much appreciated.

 

[Most Easterly Pandas]

Hello just had some drama when em light came on,I plugged in fiat ecu scan and dpf blocked !. Having not had any trouble in five years I was a little shocked and did a forced regen, after five min and a patch of melted tarmac on the road all done and no em light but the ecu scan says that it is still 80% blocked and yet says blocking is usual. Still not sure if it will need a new dpf.
Advice would be very much appreciated.

I think you'll find its 20% blocked and 80% clear, blocking number are not always as they seem.

 

[keithglos]

I Know I keep suggesting this, but have you reset the oil degradation counter, as well as the oil change?

Keith

 

[dave]

I think you'll find its 20% blocked and 80% clear, blocking number are not always as they seem.

i don't think it is because my number goes down after a mes re-gen

 

[Most Easterly Pandas]

i don't think it is because my number goes down after a mes re-gen

This is what I though happens with mine on my Bravo also.

 

[Doofer]

Is it possible that different versions of FES/MES report it differently? It's possible that the author found out about the mistake and corrected it. I think the old version I use says the oil is 100% degraded straight after a change, then it becomes less degraded as it's used.

 

[Telegraph]

Thank you all
that does make sense as 8o% blocking cant be normal and yet it says it is normal my wife has driven 30 miles and all is well .

 

[Doofer]

Keep an eye on it - if it's actually reporting that it's 80% "unblocked" then it should become less unblocked as time goes on, if that makes sense - just like the oil becomes less degraded!

 

[Most Easterly Pandas]

Recently had my dpf removed. After numerous regens, the light kept coming back on. It was cheaper than a new dpf and big differance to fuel economy and performance. Wish I'd had it done sooner.It was done at Longlife Caerphilly not sure of the phone number though.

It is however an Illegal modification, and you commit an offence every time you drive the car. In addition to this its technically an MOT failure also!

 

[stuart543]

Hi there,

I sold my Croma nearly a year ago but I still look in on this forum occasionally to see how everyone's getting on. I thought my experience could help with your particular problem as I too experienced many DPF problems until I became enlightened reading this forum and using MES. Its was a subject I paid very close attention to as I do a lot of short journeys.

The first thing to say is that in my experience anything up to 100% clogging is classified as normal clogging (higher % = more clogged) and I took numerous readings. The second point is that, again in my experience, a forced regen using the software achieves very little. I found that taking the car out for a really good hard drive was by far the best solution. I have posted on here before about how I did this (see link below). Make sure you have plenty of fuel in the tank as it won't work if the tank is nearly empty (not sure what the cutoff is). Also, I was never able to induce a regen through driving below around 80% clogged no matter how hard I drove. I have also attached a couple of MES readouts (before and after the procedure in my earlier post) taken on the same day which show the level of clogging 97% before and 24% (also classified as normal clogging) after. I've also attached a 3rd reading taken at a later date after another clearout that shows 15% classified as not clogged.

With regards to oil deg my 2nd reading shows 72% and my 3rd taken 3months later with no intervening service/reset shows 52% so a higher % means newer oil.


https://www.fiatforum.com/croma-ii/328185-p1206-limp-mode-problem.html?p=3267342

 

[Telegraph]

Thank you Stuart that's very helpful before I regenerated the em light was on and it was in limp home mode when connected to ecu scan it said it was 106% blocked after regen it said 80% emlight off and said blocking normal. We are off to Cornwall soon so It should be able to sort itself out.we don't use the Croma for short runs usually but we have been doing a lot of the off the drive on to the road and back to get my sons punto out which may have upset it!
Than you

 

[Doofer]

If you switch the dashboard computer to instantaneous MPG then if you are coasting and it displays anything lower than 99.9mpg then it's in the process of regenerating. It typically takes about 10 minutes to complete. I can sometimes sense when it's doing it these days - mainly because it doesn't slow down when coasting.

If you know it's doing it then it may help to drop a gear or two and give it some welly.

 

[Most Easterly Pandas]

If you switch the dashboard computer to instantaneous MPG then if you are coasting and it displays anything lower than 99.9mpg then it's in the process of regenerating. It typically takes about 10 minutes to complete. I can sometimes sense when it's doing it these days - mainly because it doesn't slow down when coasting.

If you know it's doing it then it may help to drop a gear or two and give it some welly.

I assume the Croma does the same as the Bravo on regen and is sluggish on instant MPG return to 99.9 mpg

 

[Doofer]

That video's excellent, and exactly what the Croma does. It makes sense, as it's squirting extra fuel in all the time, both to get the engine hot and to send some unburnt fuel down the exhaust to make it burn.

If you happen to park while it's at it then you'll notice the smell as soon as you get out, or maybe before if you've reversed.

 

[Most Easterly Pandas]

That video's excellent, and exactly what the Croma does. It makes sense, as it's squirting extra fuel in all the time, both to get the engine hot and to send some unburnt fuel down the exhaust to make it burn.

If you happen to park while it's at it then you'll notice the smell as soon as you get out, or maybe before if you've reversed.

Tbh I rarely notice the smell on my Bravo, but can always hear the cooling fan going full pelt when stationary during a DPF regen. The Croma do that also

 

[Doofer]

I can't say I've noticed the cooling fan - perhaps the fact that I live close to a motorway means that mine gets enough natural air cooling even when regenerating? Because I'm doing 70mph then only a short lower speed journey before I get home.

Either that or perhaps I just didn't notice at the time - it's perfectly possible. I know it's very audible with the bonnet open, but it seems pretty muffled once it's shut. Perhaps it's further away than on a Bravo, and/or there's more soundproofing. Or perhaps my engine sounds like a bag of nails anyway, and I wouldn't hear it over the top of it.

 

[Most Easterly Pandas]

It seems to do it on my Bravo (fan at full speed) regardless, even when I've just come to a roundabout after sitting at 60mph for the previous 5 miles on the dual carriageway. Croma might be different like you say though.

 

[keithglos]

Much better to keep driving if possible during regen, ideally above 2500 rpm.
Mine takes about 5 miles at double fuel, if I am approaching home I will kepp driving till finished.
Keith (2.4)

 

[Most Easterly Pandas]

Much better to keep driving if possible during regen, ideally above 2500 rpm.

Not sure if the Croma has the earlier system where the DPF is under the car, but on the Bravo, and most later designed vehicles with them in the manifold you're fine in stop start traffic and have no undesired affects switching off mid regen if needed

Not that it happens often as I'm not normally a city driver, but mine happily kicks in around town at <30mph.

How often do you tend to find yours regening out of interest?

 

[keithglos]

Roughly regen every 400 miles, I am very rarely in much traffic, mostly I drive about 10 to 20 miles on A roads.
The exhaust has to reach 600c before the regen is effective.
Keith