Possible diesel runaway on my 1.6TDCI?

[andy1741]

Hi All,

First of all, I own a 2009 Ford Focus 1.6 TDCI Zetec with about 119k miles on the clock.

Over the weekend I had my NCT for the car. My last NCT was 2 years ago about a week before I bought the car.

During the emissions test as part of the NCT, there was a big cloud of smoke and they pushed my car out of the test center. When I called down to the desk to see what was going on I was told by the mechanic that to get the emissions test, they need 2 recording at high rpm (he didn't say an exact figure). The first one worked fine and on the second 'the revs ran away' and they could not restart the car.

I went out and tried to start the car and it did start, albeit very rough to get going. Driven about 50 miles since, started and drove normal since.

There are 2 codes coming up on Forscan after the incident, not sure if related:

PCM - P0336-22 (CKP Sensor A circuit)

ABS - U2023-A0 (something to do with ESP light)

I rang the mechanic and he is going to have a look at the car later this week, seems to think its burning oil and this was a diesel runaway.

I did a bit of googling on diesel runaway (what it is and the warning signs). I found this forum thread: http://forums.tdiclub.com/showthread.php?t=298060 This seems to state that warning signs include:

- fluctuating idle RPM
- excess oil consumption
- oil in the intake
- excess oil pooled up in the intercooler

I have never experienced the first two of these. My car used about 300ml of oil in 6.5k miles between the last oil change. From looking around this is absolutely normal.

However when I changed the air filter last I did notice the intake pipe had a coating on oil on the inside. Now this was not excessive pooling but it was enough to show up on my finger if I wiped it.

The other thing that strikes me is that one posts seems to think this could be perfectly normal if the oil pools up over time in the intercooler from babying the car (which I am definitely a culprit of I rarely drive above 2k RPM for any prolonged period).

Anyway, to cut this short, is there anything I could check? I thought about checking to see if the intercooler was pooled with oil but other than that I don't know. I have the day off work tomorrow so I have plenty of time to investigate. I'm not a car expert and I'm good at following instructions.

Worst comes to worst and the car is burning oil, is this fixable or is the car destined for an early grave?

Thanks

[Stoney871]

Take the air filter out and look for a smaller square filter at the bottom corner of the filter housing.
That's the PCV filter.
If it's oily it may signify too much oil getting past the piston rings and therefore worn rings or cylinders.

Sent from my SM-G965F (S9+)

[andy1741]

Thanks I'll look at this. Would you expect any oil at all in the intake pipe?

[TomsFocus]

I think Stoneys confusing it with another engine.  There isn't a PCV filter to check on these.  The crank breather pipe comes from the front right of the cam cover and goes straight into the MAF pipe.  There will be a good amount of oil in the MAF pipe because of that which is totally normal.

Diesel runaways are usually caused by leaking turbo oil seals, no easy way to check that unfortunately.  You could remove the intercooler to check it, at that mileage I'd expect about half a cup of oil in there.  

[andy1741]

If there is significantly more than a half a cup of oil in the intercooler is that safe to assume that the turbo oils seals are bust then? 

As i said originally the car doesn’t consume a whole lot of oil at all, is it possible that this is just an accumulation over time and if I drain it, it should be good for a retest? 

[Stoney871]

52 minutes ago, TomsFocus said:

I think Stoneys confusing it with another engine.  There isn't a PCV filter to check on these.  The crank breather pipe comes from the front right of the cam cover and goes straight into the MAF pipe.  There will be a good amount of oil in the MAF pipe because of that which is totally normal.

Diesel runaways are usually caused by leaking turbo oil seals, no easy way to check that unfortunately.  You could remove the intercooler to check it, at that mileage I'd expect about half a cup of oil in there.  

[TomsFocus]

2 hours ago, andy1741 said:

If there is significantly more than a half a cup of oil in the intercooler is that safe to assume that the turbo oils seals are bust then? 

As i said originally the car doesn’t consume a whole lot of oil at all, is it possible that this is just an accumulation over time and if I drain it, it should be good for a retest? 

Most likely turbo oil seal if there's a large amount in the IC but I wouldn't just assume it to be that.  You should notice some oil consumption though, the last one I blew burnt a litre of oil in 12 miles as I couldn't wait for the breakdown people.

I guess it's possible that there was just a large accumulation over time which got sucked into the intake when the tester revved it but can't say I've heard of that before, even on cars that are rarely pushed hard.

It may be that an injector got stuck open if they're dirty. 

What colour was the smoke?  Did it smell like oil (plastic/rubber burning) or like raw diesel which is pretty strong?  Also is it a DPF model?

[andy1741]

On 4/23/2018 at 7:36 PM, TomsFocus said:

I guess it's possible that there was just a large accumulation over time which got sucked into the intake when the tester revved it but can't say I've heard of that before, even on cars that are rarely pushed hard.

This seems suspicious to me too. It seems ridiculous design that this could ever happen by just babying the car too much. Is it possible that this could be caused by overfilling the oil?

On 4/23/2018 at 7:36 PM, TomsFocus said:

What colour was the smoke?  Did it smell like oil (plastic/rubber burning) or like raw diesel which is pretty strong?  Also is it a DPF model?

The smoke was light grey, definitely not dark or blue. I was not able to smell the smoke as you are stuck in a confined waiting area with just a window to view the test. This is a DPF model but the DPF has been gutted by the previous owner.

[TomsFocus]

Ah that's interesting.  I was going to suggest that the oil can overfill itself if DPF regens keep failing, the unused diesel runs past the rings and into the oil.  However it can't be that in this case.  Was also going to suggest it may have tried to regen after the first hard push but again can't be that either.

Lots of things can break if cars are driven too gently, particularly on modern diesels.  Cars are designed to be driven!

With light grey smoke, it could be either oil or diesel though I'd lean more towards diesel tbh.  It may be that timing was put out by the faulty crank sensor.  Or that an injector got stuck open.

It's difficult to be more specific without seeing the car in person.