⭐️RESOLVED - Flashing glow plug warning; limp home mode; check engine light; DPF symbol​ 🤨

[gsmdo]

I was on the road this morning at just before 0500, heading from Norfolk to Bristol for a business trip. Just after an hour into the journey I got the 'glow plug' warning light flashing...

...followed by  a reduction in power as the cruise control clicked offline and the car went into 'limp home' mode. I pulled into a layby and switched the engine off and back on again - which cured it for about 30 seconds, after which it came back again.

I turned around and headed home. At some stage, about 20 mins later I think, the 'Check Engine' light came on...

...followed, with a beep, some 10 minutes later, by the DPF Filter warning light...

Oh joy.

I made it back home and plugged in the OBD Eleven and got the following:

P227900 - Intake Air System Leak
                static
                    priority -  1
                frequencyCounter -  2
                drivingCycle - 255
                km-Mileage - 170257 km

This apparently suggests an air leak. I watched our very own Gav's YouTube video on the fault, which involved doing a smoke test (which failed to show any leaks) and then the replacement of a Mass Air Sensor.  The car Gav was fixing was a later model than mine with a different engine (mine is a 2006  2.0TDi 140 with a BPW engine), but this seems a reasonable diagnostic course to follow, doesn't it?  I'm tempted to think that the 'limp home mode' for over an hour might be the cause of the  DPF Filter warning, and that an 'Italian tune-up' might well clear it.

Any ideas or comments welcome.

Thanks,

Mike 😎

PS If you're not subscribed to Gav's YouTube channel, I recommend it - used it twice this week already! 👍

 

                

 

Edited July 29, 2022 by gsmdo

[gsmdo]

OK, after a chat with my local independent mechanic, who told me that he'd never found an air leak to have caused this fault in decades of spannering, I ordered a new MAF from eBay  for £20 or so (should be here on Saturday), as well as a can of  MAF Spray Cleaner (apparently it's essential you use this - not carb or brake cleaner), so that I can see if I can clean the current sensor up enough to have as a spare.

I also rang my buddy at Audi Parts - to be told the genuine Audi part is over £300 - even with the  generous discount he's able to give me... 😱

Assuming fitting the new part clears the fault code, I'll take the old girl for a bit of a hi-rev run to clear out the DPV, which should cure that problem 🤞

I'll post up results.

Mike 😎

[Steve Q]

Good luck 😃 can't believe the genuine part is £300! 

[gsmdo]

Just now, Steve Q said:

Good luck 😃 can't believe the genuine part is £300! 

I have been driving Audis for over 30 years, but on occasion their parts prices still surprise me... 😆

[Stevey Y]

11 hours ago, gsmdo said:

OK, after a chat with my local independent mechanic, who told me that he'd never found an air leak to have caused this fault in decades of spannering, I ordered a new MAF from eBay  for £20 or so (should be here on Saturday), as well as a can of  MAF Spray Cleaner (apparently it's essential you use this - not carb or brake cleaner), so that I can see if I can clean the current sensor up enough to have as a spare.

I also rang my buddy at Audi Parts - to be told the genuine Audi part is over £300 - even with the  generous discount he's able to give me... 😱

Assuming fitting the new part clears the fault code, I'll take the old girl for a bit of a hi-rev run to clear out the DPV, which should cure that problem 🤞

I'll post up results.

Mike 😎

Hi the air leak syndrome is well documented as a cause of DPF failure as extra air is getting in to the system that the MAF is not aware of because its getting in after the MAF, this in turn causes overfuelling because the MAP sensor has reported a higher than expected oxygen pressure to the ECU which then calls for more fuel to rectify the imbalance, the extra fuel won't burn as well so it creates more soot and blocks the DPF.

If you are going to do an Italian tune up add a cleaner to the fuel like a bottle of Wynns DPF cleaner as this has a more aggressive content of Hydrocarbons which melts soot.

Steve.

 

[gsmdo]

4 minutes ago, Stevey Y said:

Hi the air leak syndrome is well documented as a cause of DPF failure as extra air is getting in to the system that the MAF is not aware of because its getting in after the MAF, this in turn causes overfuelling because the MAP sensor has reported a higher than expected oxygen pressure to the ECU which then calls for more fuel to rectify the imbalance, the extra fuel won't burn as well so it creates more soot and blocks the DPF.

If you are going to do an Italian tune up add a cleaner to the fuel like a bottle of Wynns DPF cleaner as this has a more aggressive content of Hydrocarbons which melts soot.

Steve.

 

Thanks Steve - will do... 👍

[gsmdo]

The MAF arrived in the post today...

...and seems to be identical to the OEM part fitted to the car, even down to the 'anti-tamper' five point star bolts holding the sensor in.

I also got a can of MAF Sensor Cleaner - to use on the original part to see if it's recoverable as a spare...

Trouble is, my garage and driveway are in full sun and very warm right now. I think I'm going to set an early alarm in the morning and tackle the job then...

[gsmdo]

I got bored, the sun had moved round and there was a nice breeze blowing, so I thought I'd give it a go... 😃

The first thing that struck me was that there was a lot of oil and dirt down there, by the junction of the breather and the air intake hose - and subsequently on the joint of the air intake hose to the turbo. A lot... 🤨

First things first, though. Yesterday afternoon I was clumsy enough to drop my electric screwdriver into the engine bay - if you squint you can just see it lying on the undertray...

That really is filthy... 😱

I have a couple of long reach gadgets...

...to try to reach, but it turns out that the simplest way is to unhook one of the fasteners in the driver's side wheel well and reach in and  grab it...

So I unbolt the MAF, and then the breather and the air intake pipe. I wipe some of the gunk off them in the garage using the last of a tin of brake cleaner, then cart them into the kitchen (no - Im not married... 😆).

I start by cleaning my hands and forearms with some Fast Orange, which soon has them clean.

I then run a hot sink full of water and a good dose of Fairy Liquid and take a nail brush and a washing up sponge to the parts...

This takes a while...

...but eventually they look like new...

I give the pipes a close inspection for any signs of cracking or deformation, but they both seem to be in good condition...

...and take note of their part numbers.

This breather pipe is still available new - at some ridiculous price on eBay, (€85 or so) from Lithuania. The intake pipe doesn't seem to be. Both pipes are available used from a number of sources for between £10-25 or so.

However, I don't think I'll be needing any new stuff. The breather pipe has one of those spring clips holding it on at the top end, but nothing at the bottom end, where it was leaking so badly.

When refitting, I am going to put a jubilee clip on that joint (it has a ring on the moulding to take one - I'm guessing whoever had this off last time broke or lost a clip) and I think that ought to solve the situation. I'll pop the intake ducting off in a month or so's time and have a look down at the joint to see if there has been any oily build up...

So - enough time here in the cool - time to go and refit things... 🤨

[gsmdo]

So, it's still pretty pleasant in the garage. Full shade and with a nice breeze.

The air filter is in a shameful state - I don't think I have changed it since before I went to Italy in 2017. Of course, lockdown meant I have done very few miles in the intervening time, but I'm still surprised by the state of it. I already ordered an air filter and cabin filter from eBay, but they've not arrived yet. I vacuum out the intake void, which has a fair collection of straw, leaves and dead bugs in it, then refit the dirty air cleaner...

I

I push the new MAF into place - it fits very snugly (as it should) and I secure it with the two self tappers...

I find a jubilee clip for the top of the breather hose - I reuse the spring clip for the joint at the bottom...

I fit the plug to the MAF, refit the intake pipe - which proved to be a royal pain in the parts to do. I managed to lose both fasteners into the Graveyard of Parts, as I have now named my undertray, but replaced them from my spares bin.

Anyhow, eventually it was all buttoned up, with the exception of the intake ducts and the engine cover, as I'll be replacing the air filter in a couple of days.

I am, once again, absolutely filthy after this - and go and have a good scrub with Agent Orange followed by a few cool drinks whilst I give Marnie a bit of attention...😃

I suppose now would be a good time to go out and plug the OBD Eleven in and see if it worked, eh? 🤔

[gsmdo]

So - good news and bad. I scanned the car and only the radio code came up (this is a permanent feature as I have an after-market stereo fitted) - Yay! 🥳

So - I still have the DPF filter warning on the dash. Since the car is apparently healthy in all other respects, and it's a lovely  day - what could better than to take it for an 'Italian tune up' right now, to see if I can blow the excess carbon out of the filter?

Almost straight away, I realise this isn't a great idea. Without the intake ducting fitted, the intake roar is really loud. Hey-ho - let's go.

I drive up the bypass keeping revs above 3.5k and - predictably - after a few minutes, I get the glow plug warning light flashing and the car goes into limp home mode...

I drive home and sit on the driveway whilst running the OBD Eleven diagnostic programme.

Sure enough - it's the P2279 fault code again

So - I reset it and it clears. I'm going to ignore it and leave the car in the garage until my new filters turn up; fit them; refit the intake ducts, and then take it out to see if anything I have done has made any difference.

Amazon have delivered my 5 point star bits, so I'll be able to take out the original sensor and clean it - although it seems unlikely that this was the actual problem now.

Anybody have any other ideas please?

Mike 😎

PS On the positive side - no Check Engine Light this time... 😆

Edited July 25, 2022 by gsmdo
Typos

[Stevey Y]

2 hours ago, gsmdo said:

So - good news and bad. I scanned the car and only the radio code came up (this is a permanent feature as I have an after-market stereo fitted) - Yay! 🥳

So - I still have the DPF filter warning on the dash. Since the car is apparently healthy in all other respects, and it's a lovely  day - what could better than to take it for an 'Italian tune up' right now, to see if I can blow the excess carbon out of the filter?

Almost straight away I realise this isn't a great idea. Without the intake ducting fitted the intake roar is really loud. Hey-ho - let's go.

I drive up the bypass keeping revs above 3.5k and - predictably - after a few minutes, I get the glowplug warning light flashing and the car goes into limp home mode...

I drive home and sit on the driveway whilst running the OBD Eleven diagnostic programme.

Sure enough - it's the P2279 fault code again

So - I reset it and it clears. I'm going to ignore it and leave the car in the garage until my new filters turn up; fit them; refit the intake ducts and then take it out to see if anything I have done has made any difference.

Amazon have delivered my 5 point star bits, so I'll be able to take out the original sensor and clean it - although it seems unllikely that this was the actual problem now.

Anybody have any other ideas please?

Mike 😎

PS On the positive side - no Check Engine Light this time... 😆

Hi your problem is where the pipe goes in to the turbo the rubber seal is compromised thats why its letting all the CR@P from the PCV get blown out before it goes into the engine to be burnt, this also works in reverse as it allows air in which the MAF won't have registered and you will also be loosing boost pressure, you also completely defeated the object of the whole exercise as leaving the ducting off creates the same problem as it will draw extra air from all over the surface of the air filter rather than just through the ducting which is the prime source, if I were you I would add a DPF cleaner to the fuel and give it a forced regeneration before you total the DPF and the CAT, I change my air filters about six times a year or every 9k for what they cost its a no brainer and I wouldn't mind betting thats whats killed the MAF, they are very sensitive inside to dirt as if the filter has stopped working properly it allows tiny particles of dirt into the intake system which sticks to the diode inside the MAF, the diode goes into super heat when you turn the engine off this process cleans the diode of any oily film but if you have larger contaminants it will heat up and burn holes in the protective coating on the diode which causes it to read incorrectly, whilst running the diode constantly heats and then reports the cooling time to the ECU which gauges the ambient temperature of the in comming air and adjusts the injection ratios according to the latest information from the MAFF,MAP correlation.

Steve.

[gsmdo]

Thanks Stevey, great input 👍

I knew it was an error as soon as I heard the noise the intake made. I’ve cleared the code and will not be starting the engine again until I have fitted the new air filter and ductwork. I have also got a DPF cleaner on order and my first order of business will be to put this in the tank and take the car for a gentle run, followed by an Italian tune up if the initial run goes well. 
If this solves the problem, then I’ll carefully take the original MAF apart and use the cleaner to try and refurb it as a spare.

Mike 😎

Edited July 25, 2022 by gsmdo

[gsmdo]

Stevey, having slept on it, isn't the nature of a dirty air filter to keep more stuff out of the air supply rather than less?

In a petrol engine, a dirty air filter would typically manifest itself by producing a richer mixture - ie less air is getting through and mixing with the same amount of fuel.

I'm not convinced that a dirty air filter lets contaminants into the 'clean' side of the intake box, and therefore into the MAS and this into the intake pipe. It may get dirt into the turbo from the base of the intake pipe where the breather hose was not clamped - but all indications are that the oil was coming out of that joint and plastering itself all over the surrounding area. Of course, it may only have been pushing stuff out on the overrun (and goodness knows how long it had been doing that) - but even if it was sucking air in, surely it was going straight into the turbo, where - once again - I'm struggling to see how it would affect the MAS, as it's so far downstream from it...

Mike 🤔

Edited July 25, 2022 by gsmdo

[Stevey Y]

Hi the trail starts thus, Air intake to filter box then in to MAF which registers the air temp coming in, the filter element is made of a cotton/paper mix with a porous surface of microscopic holes, thousands of them, when the material is past its best the engine vacuum will be greater than normal to reach its optimum flow rate this in turn deforms the pores in the filter material thus allowing larger parts of foreign matter into the air intake which then goes through the MAF sticking to the diode surface which as I said is constantly heating and cooling the bigger particles of matter will heat up and burn the diode surface which is covered in a heat proof lacquer which perforates and gives false readings, the last line of defence is the MAP sensor which picks up the extra air from the leak and reports that the MAF sensor readings are corrupted and the ECU needs to up rate the duration of the duty cycle of injection [more diesel] to cope withe the extra air it has logged, allied to the lost boost pressure this creates an over fuel situation which is what clogs the DPF, BTW if an air leak exists or boost pressure is lost the ECU suspends the regeneration process that naturally occurs as a safety protocol until the sensors have sorted out the communication problem this is to stop emissions from going up further, the situation you describe with petrol engines only existed with carburettor fuelled engines as the carb fuel flow rate was not monitored by the ECU where as the advent of fuel injection gave the ECU the facility to raise or lower injection cycles, most petrol engines from the early nineties with a blocked air filter would show a code for airflow threshold lower than expected and an EML, that came on when the ECU had exhausted its paramiters for cutting injection amounts, the MAF is upstream this designation is made from the calculation that the airflow comes into the box is filtered then passed to the MAF which creates circular used air into the turbine this stops air friction from warming the air as it travels in whilst creating negative vacuum to pull the crankcase gas through the system into the turbo intake, where boost pressure is lost the crank gasses do not mix efficiently with the intake air and start to atomise properly which also clogs the intercooler and DPF.

Steve

[gsmdo]

Thanks for the comprehensive answer, Steve—every day is a school day 😃

Much of my mechanical knowledge was built around carburated vehicles—mostly motorcycles, which didn’t have the systems in use in mainstream cars for the past couple of decades. The idea of a filter letting more stuff through due to an increase in vacuum is new to me 👍

Anyway, the new filters should be here tomorrow or Tuesday, so I’ll reassemble, test and report back.

This site is an excellent resource—thanks again for your detailed advice, Steve.

Mike 😎

Edited July 25, 2022 by gsmdo

[Stevey Y]

18 hours ago, gsmdo said:

Thanks for the comprehensive answer Steve - every day is a school day 😃

Much of my mechanical knowledge was built around carburated vehicles - mostly motorcycles, which didn’t have the systems in use in mainstream cars for the past couple of decades, so the idea of a filter letting more stuff through due to an increase in vacuum is new to me 👍

Anyway, the new filters should be here tomorrow or Tuesday, so I’ll reassemble, test and report back.

This site is an excellent resource - thanks again for your detailed advice Steve.

Mike 😎

Hi the revolution in injection systems started in the late seventies with the Bosch Motronic multi point injection system which must have been like the second coming for the motor industry, it spawned the likes of the Golf GTI which was the benchmark every manufacturer had to better, the early systems were expensive which is why Fords first ventures in to the arena were cars like the Fiesta Si which was basically a FOMOCO carb body with a Bosch single point injector mounted above the throttle butterfly and it was so successful in giving more power and reducing emissions they then got the hots for it and started buying loads of Bosch systems tailored to their requirements I.E. XR2i XR4i Capri 2.8i Granada 2.8i, the problem was all systems on these cars still used a plenum chamber so when CARB in California started putting the thumb screws on Ford/GM for even less emissions they started developing direct injection engines as allied to the new engine management systems gave a lot more power for even less emissions and fuel, the next revolution was again developed by Bosch was Piezo injectors, these operate on a fixed height stack of Piezo slices which when electrically charged compress and lift the injection pintle to 00.04 which is the optimal height for fuel passage then further enhanced it by giving the injector multiple injection ports which enable a good spread of atomisation, only problem is the ports are about two microns and when you consider a human hair is six microns is pretty small, then the fuel companies had to step up and remove the magnesium sulphates from fuel as this solidifies in the injectors and blocks the ports and the shame of it is magnesium is an excellent upper cylinder lubricant, any engine built 2000 on requires free flowing oxygen to allow for precise metering of fuel but only within the limits set by the management system, to much it gives problem to little its the same outcome, its all about the emissions.

Steve.

[RoyC]

I always clear my DPF on the drive.

Just keep my foot to the floor (2500 revs) until the warning light goes out.

[gsmdo]

Thanks again Steve, Roy 👍

Only the interior filter arrived today - hopefully the air filter and DPF cleaner will arrive tomorrow and I can get to testing the 'fix'...🤔

Mike😎

 

PS The good news is that Marnie is enjoying me spending more time with her...😃

[RoyC]

That dog's looking a bit guilty, check he hasn't hidden something up you exhaust pipe.

[gsmdo]

Just now, RoyC said:

That dog's looking a bit guilty, check he hasn't hidden something up you exhaust pipe.

She has previous for that guv... 😆

[gsmdo]

So, the new air filter arrived today. I fitted it, then replaced the ductwork and the engine cover…

 

…then poured the DPF cleaner into the fuel tank…

…and took her out for a drive. 
As soon as I used even moderate throttle, there was a large intake noise, followed by the glow plug warning light flashing and it going into limp mode…🤦‍♂️

I drove back home and plugged in the OBDEleven…

Sure enough, it was P2279 again.

It cleared when I asked it to, but I’m now going to take the intake pipe off to see if I’ve kinked it or mis-fitted it where it joins the turbo or something. When I last drove it, I thought the intake noise was a result of failing to fit the intake ductwork. There’s obviously some large air leak somewhere - the intake pipe has to be the prime suspect…

 

 

Edited July 14, 2022 by gsmdo

[Stevey Y]

5 hours ago, gsmdo said:

So, the new air filter arrived today. I fitted it, then replaced the ductwork and the engine cover…

 

…then poured the DPF cleaner into the fuel tank…

…and took her out for a drive. 
As soon as I used even moderate throttle, there was a large intake noise, followed by the glow plug warning light flashing and it going into limp mode…🤦‍♂️

I drove back home and plugged in the OBDEleven…

Sure enough, it was P2279 again.

It cleared when I asked it to, but I’m now going to take the intake pipe off to see if I’ve kinked it or mis-fitted it where it joins the turbo or something. When I last drove it, I thought the intake noise was a result of failing to fit the intake ductwork. There’s obviously some large air leak somewhere - the intake pipe has to be the prime suspect…

 

 

Hi its definitely the rubber section that joins the duct to the turbo, I used to get this a lot on the two Mondeo cabs I ran and after getting Pixxed off with keep paying £150 for a new inlet trunking just to get the rubber boot I finally measured the old ones I.D. Both ends I finally bought a stepped section of silicon hose that was within 2mm of the right size both ends I.E. one end was 52mm the other was was 48mm these are called reduction pieces and are available from ASH Silicone hoses on line and for about £16, that put it to bed for the next 150,000 miles until I sold the car, you might even be able to buy the boot as a repair section on eBay.

Steve.

[gsmdo]

So, having tarted about fitting carbon fibre trim inside a car I can't drive this afternoon - I thought I'd better do something about that... 😂

It being a fairly cool evening, I rolled the convertible partway out of the garage, opened the bonnet, and went through the fairly familiar routine of removing the engine cover and air ducts...

I soon had the main air pipe off...

I'd had it in my mind that I'd find that I'd twisted or kinked the lower joint of the pipe, where it feeds into the turbo (thus explaining the very loud intake roar)...

...but the pipe showed no signs of being distorted... 🤔

...indeed, everything looks as good as new. No sign of any leakage from the (now clamped) breather hose - although it's probably only done three or four miles since being replaced.

I'm a bit stumped, so I roll the car back into the garage, wash up, and open a bottle of wine.

I've bought another (used) intake pipe from eBay - it should be here on Wednesday, which, coincidentally, may well be the next time there's a civilised temperature to work in...

Any ideas welcomed...

Mike

[Stevey Y]

27 minutes ago, gsmdo said:

So, having tarted about fitting carbon fibre trim inside a car I can't drive this afternoon - I thought I'd better do something about that... 😂

It being a fairly cool evening, I rolled the convertible partway out of the garage, opened the bonnet, and went through the fairly familiar routine of removing the engine cover and air ducts...

I soon had the main air pipe off...

I'd had it in my mind that I'd find that I'd twisted or kinked the lower joint of the pipe, where it feeds into the turbo (thus explaining the very loud intake roar)...

...but the pipe showed no signs of being distorted... 🤔

...indeed, everything looks as good as new. No sign of any leakage from the (now clamped) breather hose - although it's probably only done three or four miles since being replaced.

I'm a bit stumped, so I roll the car back into the garage, wash up, and open a bottle of wine.

I've bought another (used) intake pipe from eBay - it should be here on Wednesday, which, coincidentally, may well be the next time there's a civilised temperature to work in...

Any ideas welcomed...

Mike

Hi the last thing to try is fit the new duct clear the fault, without driving it let it idle and get nice and hot and do a forced regeneration with the OBD.

Steve.

[gsmdo]

13 minutes ago, Stevey Y said:

Hi the last thing to try is fit the new duct clear the fault, without driving it let it idle and get nice and hot and do a forced regeneration with the OBD.

Steve.

Thanks, Steve - that's exactly what I had planned.

To go back to an earlier point you made - did you mean to buy a length of silicone hose (with the correct OS diameters) to replace the pipe, or just a section to fit into the bottom joint? 🤔