DPF's and RPM's

Martyn1981

Hiya, looking for some advice for my father.

I've found a few references/threads to DPF's but they don't quite fit my question, hence the new thread, unless someone can point me to a relevant discussion.

Background: My father has owned diesel cars since the early 80's and loves em. He bought a Kia Sportage last summer, but had no end of trouble with it, especially the auto stop/start. Eventually it was diagnosed as being a DPF issue, as he doesn't drive as far or as fast anymore. I believe the recommended RPM's (around 3,500 to 4,000) meant him doing the speed limit on a motorway/dual carriageway in 4th gear (not 5th or 6th).

After some negoitiating my sister arranged a swap with Kia and got a replacement petrol car for him as he wasn't advised by the salesman of the issue. In fact the entire dealership seemed unaware till they googled themselves (Kia).

Current: He's still not happy driving a petrol, and misses his diesel, and yesterday showed me a print out he'd been given by a Skoda dealership, regarding the Yeti and it's DPF, I've found it online here:

http://www.skoda.co.uk/SiteCollectionDocuments/Brochures/19246_Skoda_DPF_Leaflet_v7.pdf

"When the light shown illuminates, it means the vehicle needs help to carry out DPF regeneration. The procedure involves the vehicle being driven in a certain way to help increase the exhaust temperature. Drive continuously for about 10-15 minutes at a speed of at least 23mph whilst maintaining an engine speed of 700rpm or above. Higher engine speeds are perfectly acceptable where conditions allow."

I also found a slightly different version here:

http://www.skoda.co.uk/SiteCollectionDocuments/Brochures/15364_DPF_Leaflet_v2.pdf

"When the light shown illuminates,it does not mean there is a fault on the vehicle. It means the vehicle needs help to carry out DPF regeneration. The procedure involves the vehicle being driven in a certain way to help increase the exhaust temperature. Drive continuously for about 10-15 minutes at a speed of at least 40 mph in fourth or fifth gear (automatic gearboxes select Sport mode), to maintain an engine speed no less than 2,000 rpm. Higher engine speeds are perfectly acceptable where conditions allow."

Both descriptions seem extremely fair, and dare I say easy compared to previous advice and research. In fact the one they printed off - 700rpm and 23mph - seems almost difficult to avoid doing, but we do appreciate the difference between stop and go driving and a continuous 10-15 mins.

Question: Since my father is now 'once bitten twice shy', he's a bit nervous believing this. Does anyone happen to know if this is true, and if so, why do Skoda DPF's operate at lower RPM's, are they different, do they 'pump' more heat in?

Would you be nervous about this?

Grateful for any help or advice.

Mart.

FreddieFrugal

If he's not going to be doing the mileage needed to maintain DPF normally then he'd be better with a petrol.

It's pointless getting a diesel fitted with DPF if its just going to be a case of - short trips > DPF light > drive out of your way to regenerate it > short trips > DPF light and so on...followed by DPF failure and replacement.

Either get an older diesel that doesn't have a DPF or use a petrol which will almost certainly work out as better value for money.

My car - Ford Focus similarly requires RPM over 2000 to aid regen, not that I've ever had warning light situation due to the trips I do. It has needed on occassion, mainly winter, to chuck extra fuel in to raise engine temperature enough to regenerate, but it just does it automatically.

daveyjp

I've owned only diesels since the mid 90s, my second DPF equipped one was my last. If you aren't doing the mileage they can quickly become an inconvenient and expensive addition.

Small petrol turbos are supposed to give performance abve expected, such as the 1.2 fitted to Skodas.

anotherbaldrick

Providing once a fortnight you do a (40-50 mile ) run on A roads or motorways at 40 average, ie . a decent little spin, the DMF will be quite happy and send you no messages . There is an awful lot being talked about the problems associated with DMF's which frankly is crobblers. I drive mine as I have my previous petrol (retired , just a recreational spin when I feel like it) and have had nothing untoward, no messages from the mechanicals that I need to carry out any remedial regeneration .

Skoda Quote :-
In order to carry out the regeneration process the DPF needs to reach and maintain an exhaust

temperature higher than its normal operating temperature. Under most conditions the vehicle

is able to carry out the regeneration procedure unaided. However, in some circumstances where

the required temperature cannot be achieved, i.e. frequent short journeys or stop/start driving,

the vehicle may fail to regenerate the DPF. If this situation occurs the DPF warning light will

illuminate on the dash.

In other words unless your driving is all stop and start the engine will just get on and clean itself without any intervention from the driver who will probably not know it has happened

Edit P.S.
My car is a VW with the 140ps common rail diesel which is possibly the same engine as the OP's Fathers car.

Johnmcl7

Have you verified the information about the revs from the Kia? I don't know what diesel engine they're using but that information doesn't sound right to me, 3,500 to 4,000 revs is pretty high for a diesel.

The Skoda turbo diesel engines are the standard VW diesel engines (although Skoda garages seem good about having DPF information clearly presented, at least they ones I've seen) which themselves are fairly standard common rail diesel engines. They don't have anything in particular for clearing the DPF although the newer common rail versions of the engine were designed with the DPF in mind (the older PD engines had the DPF bolted on and were more problematic). I would expect the advice to be similar for any DPF equipped car where you need to drive at around the level the turbo comes in.

I have one of the earlier DPF equipped Euro IV cars (Octavia VRS with the 170bhp PD diesel engine) where only the higher rated diesels needed them and as the engine wasn't designed for it, the DPF tended to be more problematic. I knew this when I bought it so I avoid using the car for any short trips so I usually cycle most places and I've not had any issues with the DPF. I think if your Dad's driving was a problem for the Kia DPF, it's going to be an issue with any DPF equipped car. What exactly was happening with the Kia? Auto stop/start issues aren't what I'd expect to be caused by a DPF.

John

Ultrasonic

I'm struggling to believe the first Skoda quote about a minimum 700 RPM. What is the tickover RPM for these engines? It can't be much, if anything, below 700 RPM surely?

It sounds like your dad has a driving pattern that doesn't fit with DPFs. In which case the most sensible course of action would be to either buy an older diesel without a DPF (still plenty of decent ones about), or to find a petrol car that he likes.

Oh, and a Kia Sportage is a silly car. Your dad should buy a proper car with a lower centre of gravity that handles better and doesn't have a silly pumped up look, and associated inflated price. Just my personal, biased opinion of course!

TradePro

Martyn1981 wrote: »

He bought a Kia Sportage last summer, but had no end of trouble with it, especially the auto stop/start.

In fact the entire dealership seemed unaware till they googled themselves (Kia).

Could you maybe tell us a little more about the 'alleged' problem with the stop/start system please?

I work with Kia quite a lot, and they basically have little or indeed no DPF issues (I know many other brands do), this is probably why the Kia dealer weren't too familiar with the matter.

I think there's a good chance that your Dad misunderstood the ISG (intelligent stop/go system) if he hadn't had one before.

TradePro

Ultrasonic wrote: »

Oh, and a Kia Sportage is a silly car

I'm not a fan either, but to be fair they have just about the strongest residual values in the market, and get incredible customer satisfaction scores - not all bad news at all...

Ultrasonic

TradePro wrote: »

I'm not a fan either, but to be fair they have just about the strongest residual values in the market, and get incredible customer satisfaction scores - not all bad news at all...

Hehe, I know, but there is still a part of me that always looks at vehicles like this and thinks of them as clown cars . And I know they aren't terrible to drive, but I'd still rather have a vehicle designed for driving function rather than appearance.

TradePro

Ultrasonic wrote: »

I'd still rather have a vehicle designed for driving function rather than appearance.

I agree 100%, I think there are waaaaay too many cars out there that people buy as they think they'll look 'kewl' in them :D

Martyn1981

Thanks to everyone for info so far. Interesting to hear that VW and Skoda drivers seem happy(ish) with their DPF's.

I'll try to run through some of the answers:

@ general - I was partly aware of DPF issues and suggested my father get a petrol Sportage last June, but I failed to really stress the issue, and he loves his diesels. Currently I don't think he does enough driving to justify the costs which he accepts, but prefers the feel of a diesel, which I understand, I prefer torque to horsepower too (but with a Meriva I compromise with neither!).
So he wants a diesel for the feel, and likes taller vehicles due to back problems, so can't sit down into a car.

@ anotherbaldrick - interesting to hear you get on ok. My father does do a fair few motorway jaunts, not just city driving.

@ Johnmcl7 - I believe those RPM's are correct, that's why my sister was able to arrange a meeting with Kia, and get them to agree to an exchange, as 'regular' driving in correct gears just wouldn't be enough.

@ Ultrasonic - We're struggling to believe the 700rpm figure too. Don't get me wrong, it sounds great, and would appear to resolve the issue, but more than a little skeptical, hence my posting. Crucially I'm interested to know if it seems genuine (why would Skoda / VW fib?)

@ TradePro - I kept my head down during the faults since I'd recommended he didn't get a diesel, so my sister did the negotiating. I don't like arguing if I think I'm in the wrong.

My understanding is that he was getting a lot of electrical faults, but the main issue was the auto stop/start which I understand has to be switched off each time you start the car up (?) so he kept forgetting. Some times (after warming up) it would work (stop), sometimes not. Also if it stopped, it often didn't start back up, so he'd have to turn the ignition off and back on, whilst being beeped at by people behind.

Eventually it was the mechanic at the dealership that identified the problem. My father said that he (the mechanic) went on-line and found loads of reports about Kia DPF's, especially on one island - possibly Jersey, or something like that, where RPM's and time couldn't be managed.


So, we thought the issue was closed, and that modern diesels were possibly/probably no longer suitable for city driving, without high(ish) rpm non-stop runs. Till my father spotted this Yeti issue, and got all excited again.

TBF, he hates losing money on new car depreciation, and kept his old car (don't laugh) a Suzuki Grand Vitara XL7 for 8 years, so doesn't want to trade in so soon, but he's getting on a bit now, and just wants to be in a diesel again.

Sorry for the saga, but hopefully you can see the dilemma as the Skoda 'facts' seem incredibly easy, but so, so different to everything else we've heard.

Mart.