So my remapper has stated that an EGR delete is a very bad idea for this engine as it will mess with the DPF, whether this is because his map doesn't feature this is open to speculation. 

 

I seem to have read that many others have had a remap with EGR delete on this widely used engine without issue, but I'm no expert. 

 

I'm getting limp mode even on a steady throttle on a flat road, and a healthy turbo whistle during the frequent regens.

 

I have to do something, and the kitty won't fund a new EGR, so ...

 

1) Try another remapper?

 

2) Try EGR emulator ?

 

 

@b1ackb1rd - Ask your mapper about a DPFectomy.

I don't know the answer but dont ignore or underestimate the role that EGR plays during DPF regen.

 

My cars performance, at 108hp was never good to start with but the increased EGR activity after the emissions fix (previous owner) had almost completely blocked the intake tract leaving it pitifull.

 

I cleaned the intake tract and had the engine remapped, there was the opportunity to reverse the emissions fix at the same time but only at Celtic Tunings workshop, the lockdown prevented me from going there so a local agent did it.

 

I have now fitted an EGR  emulator so whilst the engine thinks it is happening on command nothing is actually happening, the problem is without a rollback of the emissions fix  software the regens are still at frequent intervals and now to the point of this long posting, they take many more miles to conclude or require much higher revs, this is because during a regen EGR is used to raise the exhaust temperature, that is no longer happening with the emulator/simulator and I would suggest that "mapping the EGR out" would have the same result unless you can be sure that it will still happen during DPF regens.

Edited 2 August, 20214 yr by J.R.

@KenONeillI've heard that the innards can be removed and then the opening re-welded so it's not obvious at MOT time, but what happens to the DPF pressure sensor, NOX sensor etc? Do they raise other problems?

 

@J.R. I was hoping you would have some better news regarding your EGR emulator! I'm convinced a gummed up EGR is the root of my problems. Do you this it's not working so well because the 'fix' software/hardware is still in situ? And what is your opinion of the remap, does it raise exhaust temp? Was it worth doing?

 

Pre and during regen the car is pretty undrivable car, at tickover the revs rose from 850-1000 every few seconds and when driving went into limp mode 20 times (my 10yr old kept count!) on flat roads or very slight inclines in less than 5 miles , each time it cleared when the ignition was cycled.

 

Unusually the DPF light came on which has never happened before, I normally only notice the smell and the raised revs. The light was on for only a few miles and then the car returned to its usual self - good boost, but with a transient turbo whistle which is much worse during regen for some reason.

 

Suggestions are welcomed - a search of the forum shows this is not an uncommon problem, but of the threads I've read the OP never finishes the story off so that other members can learn.

 

... perhaps the solution is to sell the car?

48 minutes ago, b1ackb1rd said:

DPF pressure sensor, NOX sensor etc?

This is why you need a mapper to do a DPFectomy.

17 minutes ago, KenONeill said:

This is why you need a mapper to do a DPFectomy.

 

Sounds like I need advice from another mapper 

I've spent this morning looking at the EGR tune to the inlet manifold and the EGR mixer. 

 

I cleaned tube and mixer only 5k miles ago, to a shine ... I was surprised to find both heavily clogged this morning (no photos, sorry).

 

Last time I cleaned the EGR mixer I turned it through 180 degrees so it was now facing the engine to try and minimize this problem. 

 

This is despite using Esso diesel, Archoil and Forte regularly. 

 

And it still goes into limp mode on partial throttle or coasting !

Does the engine use any oil?  

Oily soot seems much more likely to 'lodge' along the EGR pathways than drier soot.

 

 

13 minutes ago, Wino said:

Does the engine use any oil?  

Oily soot seems much more likely to 'lodge' along the EGR pathways than drier soot.

 

 

 

No, doesn't use any oil 

On 02/08/2021 at 11:34, J.R. said:

this is because during a regen EGR is used to raise the exhaust temperature, that is no longer happening with the emulator/simulator

I thought the converse was true; that EGR flow was reduced to zero during active regens? Traditionally, EGR use was said to reduce peak combustion temperatures? Edit: more importantly switching off EGR flow must increase available oxygen in the exhaust flow.

 

Maybe the ECU software is detecting no lambda change or upward change in exhaust temperatures when it commands this, so it gets itself justifiably confused and defaults to some longer, less efficient regen process?

 

Interesting read here, where functioning EGR system is said to be required later, post regen, in order to extinguish out-of-control fires in the exhaust system associated with regens: VAG EA189 Engine - EGR & Remap | Car Mechanics (proboards.com)  Not something I'd ever thought of.  

 

User 'valhalla' seems to know his stuff:

 

"An EGR emulator will not work, and could potentially be dangerous during a failed regen if it did;

 

The signals used to determine the EGR valve performance are at several levels - electrical feedback signal from the valve motor/positioner itself (the bit that the emulator tries to fool), then the mass airflow feedback from the MAF to determine the closed-loop performance of the valve (most significant diagnostic mechanism), plus then the plausibility of manifold absolute pressure (MAP) versus MAF to further verify the "intake model".

 

The only way an emulator would work is to simulate all three (and any other assorted "models"), at which point you might as well just use an engine, running properly, to do the job!

 

The EGR performance must be spot-on for regens, but mostly from the perspective of thermal runaway in the exhaust system (under the front of the car). It is the only viable method to starve a fire in the exhaust system, by depletion of oxygen, and bring the temperature of the DPF outlet temperature back down to safe levels again - hence it is a prerequisite for DPF regens."

 

 

 

 

This has got me thinking about a few seemingly common faults with the EA189s, DPF pressure sensor meltdowns and Exhaust gas temperature sensor 3 fault indications.

Wondering if both, but particularly the former, may be the result of this 'control of fire' function going awry due to EGR command/performance mismatch in older/high mileage engines?

i.e. the engine ECU tries to put the fire out by winding up the EGR flow (thus starving the fire of intake oxygen)  - or trying to - fails because the flow isn't sufficient and the resulting runaway event kills the pressure sensor and either damages or causes out-of-range readings from the temp sensor??

 

 

 

 

 

 

 

 

 

Edited 4 August, 20214 yr by Wino

I may have got it backwards regarding the EGR operation during a DPF regen, its late now so I wont go searching but I printed out and laminated a very good and understandable thesis on the subject, its in my workshop in France but I will be back there in a few days for a flying visit so will check.

 

Interesting to read Valhallas thoughts, my emulator does indeed fiddle with the outputs from both the EGR potentiometer and the MAF sensor.

 

I understand what he says about the thermal management of regens but is that something that actually goes on or theoretical supposition on his part?

 

Would stopping all O2 from passing through not affect the engine power or emissions? Does soot and oil ash actually burn so hot as to be too hot? I thought the burning was provoked by post combustion injection of fuel to be scavenged directly to the DPF, in that case the logical thing would be to stop that if the DPF temperature gets too high, what he is talking about sounds like a chimney fire but can that actually happen?

 

If you think that it can an does then I need to do some live data recording (not that I know how!) during a regen both with and without the emulator.

 

I dont like having something that I dont understand how it works, with this I do but I am in doubt as to whether I know all the consequences, I am a chancer in life but like to know when I am taking a risk and what the outcome could be.

Chimney fire is a good description of an active regen, I would think. 

One that is deliberately initiated, monitored and controlled though.

Control oxygen availability and you have a fire that you have a good chance of extinguishing if temperatures get a little wild. 

 

I wonder how many folks with DPF and EGR issues would actually mind that much if there was a runaway event ? 

On 04/08/2021 at 13:59, Wino said:

I thought the converse was true; that EGR flow was reduced to zero during active regens?

 

User 'valhalla' seems to know his stuff:

 

The EGR performance must be spot-on for regens, but mostly from the perspective of thermal runaway in the exhaust system (under the front of the car). It is the only viable method to starve a fire in the exhaust system, by depletion of oxygen, and bring the temperature of the DPF outlet temperature back down to safe levels again - hence it is a prerequisite for DPF regens."

 

 

I said I would get back to you when I had a chance to read the DPF regen stuff from VAG, by coincidence I had just been driving around allowing a regen to finish and pondering why it was even doing one when I did a 5 hour motorway journey last night towing a 2.5 tonne trailer at a fair lick of speed, I can't believe there was any soot remaining to burn off, it has confirmed my suspicion that the emissions fix regens happen on calculated soot loading and not measured soot loading from the DPF differentiel pressure sensor.

 

EGR is stopped during regens so my emulator can only be helping all the time.

 

Not sure if Valhalla does know his stuff, whilst EGR will reduce the oxygen level in the exhaust gases there is no way to "starve" an exhaust fire of oxygen on a diesel engine with no throttle butterfly, the only conditions where it could happen is under full load at max revs with the engine taken beyond its volumetric efficiency, wheezing for air and all the oxygen being burnt with the diesel injected, at any other time and especially on light throttle openings or the over-run the DPF is having air pumped at it like the bellows on a blacksmiths forge.

17 minutes ago, J.R. said:

 

Not sure if Valhalla does know his stuff, whilst EGR will reduce the oxygen level in the exhaust gases there is no way to "starve" an exhaust fire of oxygen on a diesel engine with no throttle butterfly, 

 

I believe that the Anti Shudder Valve can do just that thing.  I understand that it performs this role in some DPF regeneration scenarios.  Hence the, incorrect to my mind, increasing use of the term 'Throttle Body' to describe it.  

Rather than being the digital, open / closed device which it was prior to the fitment of DPF's, it now performs in a more analog way, closing partially and inhibiting the intake of air during a regen. 

Good point, I had overlooked that.

 

I think that it is perhaps the correct term for recent generation of engines, its primary purpose is not to prevent shudder but to pull exhaust gases through the EGR, the shuddering happens when it gets clagged up & cannot close properly.

 

Editted, thats exactly what you said, my apologies!

 

Now I have a whole new avenue of thought to contemplate what ills my EGR emulator might be doing in different circumstances, when the engine thinks it is recycling ehaust gases but isn't the cylinder filling on the intake stroke will be being restricted.

 

The more I think about this the more I want the missions fix to be rolled back & to put everything back to stock, these engines performed just fine before VW's trickery was discovered.

Edited 6 August, 20214 yr by J.R.

7 hours ago, Schtum said:

 

I believe that the Anti Shudder Valve can do just that thing.  I understand that it performs this role in some DPF regeneration scenarios.  Hence the, incorrect to my mind, increasing use of the term 'Throttle Body' to describe it.  

Rather than being the digital, open / closed device which it was prior to the fitment of DPF's, it now performs in a more analog way, closing partially and inhibiting the intake of air during a regen. 

 

Yep, and not just during regen operations for fire control.

Any time the engine management wants more EGR flow (for NOx reduction) than could be achieved without this throttling of intake airflow.

 

Edited 7 August, 20214 yr by Wino

Well the hateful CAYC lump in my car is still giving huge problems; after a month of blanket bombing with Esso, Forte, Wynn's Injector Cleaner and ECP DC980 the car has been freeing up nicely and limp mode events have been rare.

 

However, today things changed - on the outward journey to Kenilworth today (30 miles) the car was perfect, good boost and no issues. 

 

The return trip was a different matter; 40+ limp mode episodes which happened in a while variety of situations including in town, at traffic lights, coasting downhill, driving uphill and slightly lifting the throttle, overtaking in lane 3 of the M42 and a few miles later still on M42 there was a firm but brief thump from the engine which focussed my mind somewhat. 

 

Carista gave a range of error codes, none of which can be searched including; 07336, 07462, 07385, 09839

 

I am due to take it to Cornwall soon, a round trip of 500+ miles but I have NO faith in the car whatsoever, the limp mode events are manageable but if this escalates ...

 

Much as I love the car, I think it will be gone before the end of the month. 

@J.R. Any update with your EGR simulator? I'm edging closer to a purchase and I'd be interested in your progress

Well it is doing its job of not allowing any EGR perfectly without any side effects or fault codes as it always has done.

 

I do however seem to be having very frequent regenerations often after long runs towing a very heavy trailer when I would expect passive regens to occur.

 

I cant say what the frequency is because I keep leaving my VCDS in another country, an app is out of the question for me.

That's good enough for me, I'm not looking to do VAG's development I just want my car to run ok. 

 

As to apps in the absence of VCDS; the Carista dongle is useful for logging regens, ash residue etc using VAG DPF, and the Carista app can be used to start a regen - personally I think it's pretty useless for anything else, but the dongle is £25 so hey-ho.   

Hello I am installing a TAFMET EGR simulator in my 1.6 CAYC and cant find where to plug it in on the egr side has anyone had experience installing this or have pictures to help guide whereabouts i would find this, the MAF sensor is very easily accessible but cant seem to find an egr plug unless i have to access this from beneath? Many thanks in advance

Welcome to the forum.

@J.R.might see this now. 

I replied to your message and am repeating it here for the forum.

 

I have a different vehicle & engine but the EGR position is probably similar because I could not see the connector either, I traced the loom to it and removed it by feel, by the time you get your arm down there you could not see anything anyway.

 

Having now done it a couple of times its become easy but releasing the latch on the connector whilst pushing the connector in and then pulling it out while keeping the latch disengaged all with one hand and by feel takes a lot of doing, I fed a long screwdriver down by feel into the right position to release the latch and used my other hand to push it.

 

If you think about the positioning of the unit and how you run the sub loom to the MAF sensor the whole installation can be completely invisible, you would have to be on the look-out for modifications and then remove the air trunking to see that mine has been fiddled with, they use an identical piece of loom and connector for the MAF sensor which is the only visible part.

Eventually got it was a nightmare getting the egr plug off. I used a 2ft long screwdriver from the top to push down the light grey connector that can be seen by looking down to push the tab then getting someone to pull the plug out from the underside this also made connecting the new plug alot easier.

 

Overall there's not much disassembly just the engine cover and undertray it's just the egr plug which is a nightmare to remove 

 

Thanks to @J.R.for the advice