Turbo, EGR and Intercooler maintenance

[Marco34]

I've been reading from various resources (such as TDI forums) about the maintenance with the intercooler. Many people suggest flushing it with detergant, others say that a film of oil will soon return so unless you clean the intercooler frequently it isn't worth doing.

Are the turbos on a 1.9TDI variable vane or do they have a wastegate?

Also, the EGR becomes blocked with fumes from the PVC. I took the hose off mine whilst running and noticed vapour was coming out. I assume this to be normal. What are peoples views on the above particularly the following:-

1. Is it worth flushing the intercooler?

2. Is it worth disconnecting the PVC pipe to prevent contaminated fumes going back through the turbo. (reason for so much gunk in the intercooler)? or does the MAF expect this blow by to be pushed back in thus causing issues.

3. EGR - I assume this is the metal piece on top of the intake. I am pretty proficient with maintenance but the diesel engine is new to me along with Turbo's etc. Anyone have any pics per chance? Is it worth cleaning!?

If anyone has done the above have you found information on what to do? I'm a bit stumped as to how all that pressured air returns back to the inlet from the intercooler. The pipe running from the back engine to the intercooler does not seem able to cope with high pressure. The join from upper pipe to the lower one seems to be a large C clip and doesn't seem a mega seal to withstand pressure. Am I missing something?

Any gurus on the subject or you know of any good literature regarding the above please let me know. The more I've read the more cloudy it seems. :aargh4:

Many Thanks.

[Col]

At lot of that info applies to US TDI's where the diesel is really bad quality wise.

Whilst here in the UK we do suffer from the egr sooting up, it is not as bad. Cleaning is a good idea though if you suspect / know it is clogged.

As for washing out the IC and turbo maintenance.... a damned good thrashing at least once a week under all load conditions will keep everything free'd off and working nice !

If you drive like a sunday driver all the time, you are asking for trouble, the TDI's need to be excercised !

[Marco34]

BigCol thanks for your repsonse. Just one thing. I can appreciate that hard run will help but what does driving hard do? Does it simply increase pressures so high that the crud is blown out and burned by the engine. I thought this would be good for internals but does this also work for the turbo, egr and intercooler?

Cheers

[ini]

A good long run is good for VNT turbo engines (110+bhp and PD engines)

On your car the intercooler and egr will get fouled with oil, as the turbo oil seals tend to seep and the oil collects in the bottom boost pipe and blows up to the egr.

It may be worthwhile reducing egr operation slightly too.

[Col]

BigCol thanks for your repsonse. Just one thing. I can appreciate that hard run will help but what does driving hard do? Does it simply increase pressures so high that the crud is blown out and burned by the engine. I thought this would be good for internals but does this also work for the turbo, egr and intercooler?

Cheers

A good thrash ensures that the vnt mechanism works throughout its entire operating angles. The increased airflow will also help blow things through on the exhaust side. Note that the inlet side should have nothing to blow through other than a bit of oil mist, which leads me on to...

The oil that sits in the IC is mainly from the crankcase breathing system and will quickly return therefore in my opinion, cleaning out the IC is pointless.

[Dave Avant]

1. I've thought about this, but as said it will oil up again.
2. What is the PVC?
3. Disconnect the EGR, it really only works for the first few thousand miles when the engine is clean and new. After a while it cokes up and the engine can smoke a bit. I've disconected mine and it doesn't smoke. EGRs are the main cause of MOT smoke test failures as they put all cack in the inlet. I proved this by disconnecting an EGR on a car that kept failling, after it was disconnected it passed. Granted it effects cars more which do short journies and ones which don't see 4Krpm much. :D (yes it is the silver flying saucer looking thing which pokes through the engine cover.)

The passage of air; :D
Air enters air box, thru filter, then Maf which measures the volume of air, then it enters turbo which it is compressed and pressurised which in turn heats the air. It is now pushed through the intercooler to cool it back down as cooler air is denser giving a better ignition and more power. Then its up and round the back of the engine where it passes the EGR and into the inlet and finally the engine. The turbo is driven by exhaust gases which turn the propellor which on the other end of the shaft is another which does the compressing of the air for the inlet side of things. The EGR basically allows some exhaust gas to instead of going down the exhaust goes into the inlet manifold to be reburnt by the engine. The EGR is shut when under load or accellerating as otherwise the pressurised air from the turbo via intercooler will be lost into the exhaust rather than going into the engine. The idea is the emissions are reduced due to recycling, but instead it put dirty exhaust gas back into the engine which eventually cokes the inlet to the engine actually increasing emissions!!!

BMW had a similar idea on petrols where they used a hairdrier type thing to inject fresh air into the exhaust to reduce emissions, but it was more a cheat than actually reducing emissions!! :D

[Vdubba]

[quote=Dave Avant;48587]1.
Disconnect the EGR, it really only works for the first few thousand miles when the engine is clean and new. After a while it cokes up and the engine can smoke a bit. I've disconected mine and it doesn't smoke. EGRs are the main cause of MOT smoke test failures as they put all cack in the inlet. I proved this by disconnecting an EGR on a car that kept failling, after it was disconnected it passed. Granted it effects cars more which do short journies and ones which don't see 4Krpm much. :D (yes it is the silver flying saucer looking thing which pokes through the engine cover.)

The passage of air; :D

hey thats a good explanation of how the system works thanks!


by disconnecting the egr:
1.will it do any damage?
2.do you just need to disconnect the vacuum pipe and block it?

cheers :beerchug:

[onzarob]

this link is great in understanding the vnt turbo action.

http://www.technologie-entwicklung.de/Gasturbinen/VNT15-Turbo/vnt15-turbo.html

so a good thrash will burnt allot of the crud of and help it move freely.

[Dave Avant]

[
hey thats a good explanation of how the system works thanks!


by disconnecting the egr:
1.will it do any damage?
2.do you just need to disconnect the vacuum pipe and block it?

cheers :beerchug:

1. No, think of it as an add on and not an integral part of the engine or inlet parts.
2. Yes this is what I have done. I did remove it at first and gave it a bit of a clean, really to make sure its working properly, but then decided to 'blank' it off. It does needs to be kept in the closed position. It could get stuck open, but I would think there would be performance issues if it had.

you won't see any performance gains, unless it has stuck open. But I did notice before I did blank it off after a good accelleration, it produced a haze of smoke when I looked in the rear view mirror, more noticable at night in following car headlights, but now I must say I can't see any.

[Dave Avant]

this link is great in understanding the vnt turbo action.

http://www.technologie-entwicklung.de/Gasturbinen/VNT15-Turbo/vnt15-turbo.html

so a good thrash will burnt allot of the crud of and help it move freely.


:beerchug: Always wondered how the variable vane turbo worked. I thought it was 2 impellors that worked together with one being smaller for the 'light' boost and a bigger vaned impellor for the higher boost.

[Marco34]

Thanks for all those responses. I've not studied the EGR closely so not exactly sure what to disconnect. I will give that a go as I've noticed a haze when acclerating hard. My journeys are quie short to work and don't get the opportunity often to give it a good drive in the week. I'll inspect the EGR and disconnect and see how it goes.

Cheers

[ini]

Completely disabling the EGR is not recommended long-term if you regularly make very long journeys.

Because as well as reducing oxides of nitrogen, it also functions to reduce exhaust gas temps.

Disabling it should result in a little more mid-range power.

[Dave Avant]

Thanks for all those responses. I've not studied the EGR closely so not exactly sure what to disconnect. I will give that a go as I've noticed a haze when acclerating hard. My journeys are quie short to work and don't get the opportunity often to give it a good drive in the week. I'll inspect the EGR and disconnect and see how it goes.

Cheers


Disconnect the black plastic pipe (10mm as I remember) attaching to the top of the 'flying saucer' and plug it, I used a small bolt.

[Dave Avant]

Completely disabling the EGR is not recommended long-term if you regularly make very long journeys.

Because as well as reducing oxides of nitrogen, it also functions to reduce exhaust gas temps.

Disabling it should result in a little more mid-range power.


It can reduce exhaust temps, normally on part throttle or motorway cruising, but it is still an 'emission' add on and isn't detrimental to the engine. After all, not every engine is fitted with an EGR. :beerchug:

[ini]

I know what you are saying, but the management system and piston material etc, has been carefully designed to function in a certain way.

Totally removing the EGR will result in increased long term wear.

On the other hand, the EGR is my enemy, i dont like it and have removed its function from my car. :D

[Dave Avant]

Totally removing the EGR will result in increased long term wear.


Thinking about it though, the soot and carbon etc going back through the EGR and into the inlet/engine surely must have some 'wearing' particles in it? :confused: :D :beerchug:

[ini]

The soot is pretty soft stuff, and VAG made a good engineering investment in the high grade combustion chamber materials.

Cycling high temp is a more serious longterm killer + for turbo life.

[Dozz]

This has been discussed on many forums at length I had a pajero and blocked egr valve off and had no issues 30k miles the bit which really confuses me is the bit about it helping with cooling. Instead of taking nice cold dense air from the outside you take super heated burnt gases and bung them back in hmmmmm just dosen't add up

[a8 tech]

login 11 enter 12233 and the groups 1,2,and three in adaption channels can be adjusted.Increase the fuel quantity and reduce the egr duty cycle.Before attempting to adjust record the engine ecu values in these channels so you can reset them.This will reduce egr operation and increase and smooth out fuel and idle settings

[onzarob]

By how much would you recommend changing these A8_tech? I keep thinking i should do this.

[ini]

When i say long term damage, i am talking about distances of maybe 100k miles. (fleet/motorway cars etc)

With local journeys and short commutes, most TDI's never even reach operating temperatures.

VAG-COM does not seem to disable the EGR enough on my car, and i ended up just disconnecting the tube and sealing it.

[a8 tech]

When you try to set the minimum egr it will only go so far so when you have found the lowest setting save it and the same with the fuel when you find the highest value you can set then save it.Dont forget to keep a copy of the original values and dont worry your not going to damage anything by adjusting these values

[Dave Avant]

When you try to set the minimum egr it will only go so far so when you have found the lowest setting save it and the same with the fuel when you find the highest value you can set then save it.Dont forget to keep a copy of the original values and dont worry your not going to damage anything by adjusting these values


Is this done via VAG com?

Just as a side topic, my 1.9TDi 130 shakes on idle, bit like having a big panting dog in the back, but only when fully warm, after driving for 1/2 hour and when the weather is warm. The cambelt was done at 59K as I'm sure I read the injector values have to be checked afterwards, I bought the car with 65K and has done 70K now. I did try a 'tuning box' (in winter) but this made it shake alot so sent it back and it was fine, but now the weather has warmed up it has started shaking. I pressuming its fuelling as the T box added extra fuel basically and its the same shaking at idle. Haven't had it VAG com'd yet to see if there are errors.
Any info if you can would be great. :D

[Dave Avant]

This has been discussed on many forums at length I had a pajero and blocked egr valve off and had no issues 30k miles the bit which really confuses me is the bit about it helping with cooling. Instead of taking nice cold dense air from the outside you take super heated burnt gases and bung them back in hmmmmm just dosen't add up


Think of it as, the gases are being 'reburnt' so they won't burn as much 2nd time through thus the heat generated isn't as high. It effectively reduces the amount of 'burnable' gas as part of it is 'used' gas reducing power and exhaust heat. Thats my take on it anyway.

But a diesel doesn't have exhaust temps of a petrol counterpart so the turbo isn't going to be overheated by disconnecting the EGR.

[a8 tech]

Channel 1 is the fuel quantity and you can set it to the maximum 0f 32784.Channel two is the idle speed and you can set that as you wish.Channel three is the egr and you want to reduce this to the lowest setting which i think is 33638.

[marcus_ishere]

Now, this is what has happened. I agree once you get a new vw or audi the car is going to need that thrashing. But, if you have bought a used vehicle (which I have ) the egr, turbo and IC all have incredibly caked and coated gunk. It's taken me 16 hours so far to get my car apart and back together. Five of those hours were spent just cleaning parts. YES, if your car is the US version, clean everything. I had 1/2 of an inch of hard buildup in everything. Causing an error p1556 boost pressure negative deviation. which causes the failure of your MAF. Next week, Im taking off the head, scraping the gunk off of my pistons and cylinder heads.. Guess what? My car with a little routine maintenance.. will run 300+ thousand.. Good luck kids.

[Dave Avant]

Now, this is what has happened. I agree once you get a new vw or audi the car is going to need that thrashing. But, if you have bought a used vehicle (which I have ) the egr, turbo and IC all have incredibly caked and coated gunk. It's taken me 16 hours so far to get my car apart and back together. Five of those hours were spent just cleaning parts. YES, if your car is the US version, clean everything. I had 1/2 of an inch of hard buildup in everything. Causing an error p1556 boost pressure negative deviation. which causes the failure of your MAF. Next week, Im taking off the head, scraping the gunk off of my pistons and cylinder heads.. Guess what? My car with a little routine maintenance.. will run 300+ thousand.. Good luck kids.


Buddy hell, thats what I call a good cleaning.

[Dozz]

Buddy hell, thats what I call a good cleaning.

Wonder if he wants to clean my kitchen ;) ;) ;) ;)

[a8 tech]

You must been running it on coal.

[paulalexmac]

Hi there, I know that this is prob the wrong thread to reply to, but wanted some input.
My 2005 Golf 2.0GTTDI has a faulty EGR regulator flap, according to my local garage. It has only done 27K miles and is 4 months out of warranty (as it was an import). Going to cost me nearly £400 to get it sorted.
£270 (+vat) for the part, £50 for fitting.
Does anyone know if that is a reasonable price for the part?
I have found the part on-line for 224 Euro (+19% vat) but reluctant to buy just in case it is the wrong part.
Also wondering how it could have gone after such a short time/mileage.

Any input would be greatly appreciated.:1zhelp:

[a8 tech]

Yes there about £300.Not cheap for what they are.The motor sticks and causes internal short circuit.It is a common fault on the A3 2.0 tdi and Golf

[paulalexmac]

Thanks for that a8 tech. :beerchug:

Have just booked in car for friday. :(

Just as well it is payday this week.

[paulalexmac]

What is the sign for the Reg Flap going then?
At the mo the car performance is normal, the only reason I went to the garage is that when the engine is turned off there is a clicking sound that comes from the Reg Flap/EGR Valve area. It sounds like a solenoid.
It clicks 9 times every time the engine is switched off.
If just the ignition is turned on then off again, without engine start, it clicks 7 times.
Periodically it will click only one or three times.
Very odd. :confused:
My mechanic said that he had never heard one do that B4, they just usually stop.

Have you heard of this B4 a8 tech?
Or has anyone, 4 that matter?

cheers paul

[a8 tech]

The reason you have no running issue is because the flap intake manifold flap is only used when you turn the engine off,it shuts the air intake off so your engine stops instantly.If the flap has broken away from the motor you can expect the motor will still operate from the open closed pre set position.But i would expect it to move only once,wierd.

[paulalexmac]

Glad to know that I seem to have a unique problem.
I feel all special. :biglaugh:

Wish it wasn't going to cost me tho. :(

[a8 tech]

Channel 1 is the fuel quantity and you can set it to the maximum 0f 32784.Channel two is the idle speed and you can set that as you wish.Channel three is the egr and you want to reduce this to the lowest setting which i think is 33638.I have done this adaption today and the 130 a4 flew after altering the fuel and egr,the driver was very happy with the acceleration after and thought id chipped it:beerchug:

[Dave Avant]

I have done this adaption today and the 130 a4 flew after altering the fuel and egr,the driver was very happy with the acceleration after and thought id chipped it:beerchug:

I see with my beedy eye you are in the NW, do fancy a quick look at mine - I presume this is done with VAG com. Plus to see if my slight shake at idle is a fault. Obviously we can arrange a financial agreement :beerchug:

[a8 tech]

It could be arranged but not in july unless you are very close to st helens

[Marco34]

Interesting you mention the idle shake... mine is exactly the same description... only happens when warm and common in warmer weather. I'd be interested to know how you fix that one.

[Marco34]

a8 tech, that is very interesting what you have done using VAG. I've downloaded the software but need to get hold of the hex com or hex com can?? cable. They all seem overly expensive!! £200 ish. Where did you get yours from and what type exactly was it?.. cheers

[Dave Avant]

Interesting you mention the idle shake... mine is exactly the same description... only happens when warm and common in warmer weather. I'd be interested to know how you fix that one.

I'll let you know if I get it sorted!!

Also do you find it either stops or doesn't do it as much if you put the aircon on (switch ECON off)?

[Marco34]

I'll let you know if I get it sorted!!

Also do you find it either stops or doesn't do it as much if you put the aircon on (switch ECON off)?

To be honest I havn't checked that! I'll let you know. I don't do long enough journeys daily to have the problem. I've read somewhere that it could be the engine mounts! Apparantly they are electronically controlled and the sensors go. Don't quote me on this but it's another avenue to pursue. I'm loathed to have to give it to Audi!!!!

Do let me know if you fix it as idling when in queues can be a real shakey time!! :zx11:

[Dave Avant]

Yeah, I've heard it can be;

Temp sensor
Injectors out of sync (Usually adjusted/checked after a cambelt change)
fuel filter
MAF
Engine mount

Has yours had a cambelt change? Mine was done last April by Audi before I got the car. Just wondering if the injector sync is a possible cause after the belt change.

[Marco34]

Yeah, I've heard it can be;

Temp sensor
Injectors out of sync (Usually adjusted/checked after a cambelt change)
fuel filter
MAF
Engine mount

Has yours had a cambelt change? Mine was done last April by Audi before I got the car. Just wondering if the injector sync is a possible cause after the belt change.

Interesting you mention the cambelt. I had mine done last year too and although I can't say it happened immediately after, it only started last year! I've fitted a new temp sensor in hope of fixing the temp gauge issue I have. New temp sender didn't fix that! I replaced the fuel filter last year too, and have recently replaced and cleaned the air intake. The MAF looks like new!

I don't understand how the cambelt affects the injectors? How can the injectors be out of sync? :confused: Another unknown prob me thinks :aargh4:

I'm off for the Silverstone GP so my engine will have time sat idling when hot so I'll see how it behaves after a long run!!

Cheers

[onzarob]

I don't understand how the cambelt affects the injectors? How can the injectors be out of sync? :confused: Another unknown prob me thinks :aargh4:

Cheers

The cambelt is the key to the timing of the injectors. the position of the injection pump in relation to the crank and cam is the basic principle for how a diesel works.

[Marco34]

The cambelt is the key to the timing of the injectors. the position of the injection pump in relation to the crank and cam is the basic principle for how a diesel works.

I understand the element of timing with the injectors, but surely that should be checked by Audi. I would have thought everything would be marked and not moved whilst the belt is removed/replaced. If the the belt was a tooth out I wouldn't have thought the car would even run. Another conundrum!!! :confused:

[onzarob]

It is fixed into positon when changed, but there are small ajustments that can be made to get the timming spot on.

you don't say which engine have?

[Col]

I understand the element of timing with the injectors, but surely that should be checked by Audi. I would have thought everything would be marked and not moved whilst the belt is removed/replaced. If the the belt was a tooth out I wouldn't have thought the car would even run. Another conundrum!!! :confused:

With everything locked up you only obtain the basic settings if it is an old rotary pumped engine, PD's sort their own timing out once the basic settings are achieved.

The rotaries need to be hooked up to the VAG computer or Vagcom etc and the timing measured from their dynamically. If adjustment is needed it can then be adjusted via the pump.

[Marco34]

I have a 1.9TDI 130 PD, 2001. Should this be ok for timing then as mentioned by BigCol?

Trying to elminate allsorts for the engine shaking! :zx11: