1.9 TDi Vacuum Pipe Connections

[Israar]

Hey guys, hopefully this will be of much more use than my lame excuse for describing problems, as my problem describing can be very poor at best!

Anyway, from what I know of and from the amount of vacuum diagrams I've check, a pipe that is not currently connected should be connected from the looks of all the similar engine code diagrams to my N75 Turbo Solonoid.

Though that has a black plug like connector on the atmosphere connection which again should be connected from the looks of it to the Air Filter but T-lined to the same connection from the N18 EGR Solonoid.

On to my pictures then reference pictures used.

Here's my own personal hand drawn image of how my pipes are currently hooked up.

The black plug like stopper (not a clue what this is )

Connection to the Air Filter showing pipe from N18 Solonoid with the disconnected pipe coming from the T-line which by rights should be connected to the back (Atmosphere) of the N75 Solonoid though as you can see there is the black plug like stopper...

Here is a link to all of the pictures taken of my pipe work, there is more pictures there than there is that I've put up here, 11 pictures in total. Israar's Vacuum Pipe Connections 14.4.15

There reference pictures I have been going over are one that Muttley drew up himself

One that I found scouring the internet that looks VERY similar if not identical to the way mine is supposed to be

As I've mentioned, though I'll restate this I have got my EGR blanked off with plates (which a garage did for me and they also changed my turbo too), I'm unsure on whether or not they fitted this black plug when they blanked off my EGR or whether it was there when I originally bought the car. Like a numpty I never took pictures of the car under the bonnet before I bought it for reference...

The black plug like stopper seems pretty tight, though going over my pipes some of them seem soft like they have worn away somewhat over the years (which is bound to happen anyway).

My question is, does anyone know what effect would be happening with this the way it is? What might be happening? What would happen if the black plug was removed from the N75 and the disconnected pipe put back on to the N75 with the EGR valve being blanked off with plates?

Hope this can shed some light and hope you all like my drawing hahaha!

Thanks in advance!

--Lee

 

[Muttley]

I've gone over this thread, and your other comments, and my old pics of my ASV-engined Toledo, and the valve in the N75 position is not like the one I had.

I wonder if it is a generic replacement valve that has its own intake for atmospheric pressure (around that back of that big black plug somewhere). It *must* have an atmo pressure intake somewhere, in order to work the turbo vanes, if it didn't you'd have no control over boost pressure.

The Elsawin-like diagram you've found says it's from an ALH engine (bottom right corner). ALH is the last of the TDI 90 engines and is basically an ASV with a lower power map... earlier TDI 90's (1G, AGR, AHU) had wastegate turbos but ALH has a VNT turbo, with variable vanes.

Your hand-drawn diagram is great, matches up with mine so you confirm that I got it right when I traced all those boodly black pipes myself

 

[Israar]

Hi Muttley, thanks again for your input, I really am struggling with this, the more and more I'm thinking about it the more I'm wondering what the hell this plug is on the N75 and why it is there, what purpose has it been put on and what duty does it have?

I'll have to check to see if there is some kind of part number on it or something, so I can figure out just what the hell it is. From the looks of the pictures I have taken, I'd safely wager it not having any form of atmospheric pressure directly in to the N75 at all with that plug there. I'll definitely pop the bonnet after a sleep to see if there is an open air way for it but I highly doubt it as the thing is quite attached to the N75.

I checked last night, with the back of my hand to see whether the pipe that isn't connected up was blowing or sucking air, and it's very very gently blowing, I could barely feel it with it about 1mm to 2mm to my skin by my vein.

If it definitely doesn't have an atmospheric intake, which by the looks of it it doesn't. What exactly will it do apart from give me no control over boost pressure? I know my turbo seems to kick in when it feels like it, and sometimes it just doesn't want to go. When it does go it doesn't give me the kick my old turbo did when that wanted to boost. (The old turbo had very sticky vanes, they where seized up quite badly!)

See I don't believe I know enough quite yet to be mauling with my vacuum pipes as in rearranging them? I am very curious though as I want to know what would happen if I had an actual atmospheric connection to the N75. Am I right in saying plugging the unconnected pipe on the N18 would do nothing or am I wrong to think that?

How different was the N75 you had? I noticed that the diagram I found that's pretty much identical to mine is for an ALH engine, I didn't mention that though it should have been mentioned, I just can't find anything relating to ASV engines, since most abbreviations for ASV are to do with the Anti Shudder Valve lol

Thank you hehe, I'm just glad we have 2 versions now, yours and a "dummies" version hehe!

Also, concerning the curiosity with wanting to know what would happen with testing with an atmospheric connection to the N75, I am definitely not sure if I have a leak or not, not yet tried to check though I know some of my pipes are quite worn through age.

With the turbo too, you can hear it, do you think it is worth while doing a recording to hear the turbo and rev a few times (while the engine is warm) to see if there is anything to listen to or whether it will do anything as to help with solving this out?

I'm stuck as to who to go to concerning this block, I can't seem to find anything on the internet to do with it I am going in for a power test after pay day so I will know what the car is pushing at present but I doubt it will be 108 which is what it's stated (considering it's age, although I though you'd lose bhp over the years from things I've read yet when I asked a remapper about this theory I was told not to believe that)?

I believe this is the most I've been confused yet curious and eager to find out and fix a problem haha!

Do you think it's worth while getting a brand new N75 and hooking it up like it's supposed to be and see what happens? I have vag com (or vcds lite not registered yet as I don't have the money for it) so can't take logs, as I was thinking of checking anything that's worth while checking?

A sleep is in order now as my minds just turning to mush haha

Catch you later mate, hopefully we can come to finding the truth of this little black plug soon!

--Lee

 

[Muttley]

Your valve looks like this one.

http://www.ebay.co.uk/itm/Turbo-con...fe1c9&pid=100204&rk=11&rkt=30&sd=251805800119

This is listed as an OEM part for the N75 function on 1.9 TDI Audi A4, A5 and A6 up to 2008. These engines all use the same component set as ours, even though they are mounted fore-and-aft in some cars. The turbo is still a VNT turbo, like ours. So it must be doing the job you need, without looking quite the same.

Do you have any paperwork from the turbo replacement job that tells you what kind of turbo they put in and if they also changed the N75 valve?

If you can find a part number it would help us find out more info.

You said

Am I right in saying plugging the unconnected pipe on the N18 would do nothing or am I wrong to think that?

Do you mean that there are other unconnected vacuum pipes in your engine bay? From what I can see, the N18 valve is still there so I'd guess it's still connected to the EGR valve, even though this now does nothing useful. It would not hurt to plug the unconnected line you have shown us, just to keep things clean.

I have not found the pics I took of my old engine bay, but it looked exactly like the one in the picture below, which was also an ASV, that someone else has annotated - I added the solenoid valve names.

I think your turbo is working pretty much as it should, but since you have an N75 valve that is not the same as the original it is possible that the response is different. As far as I know the different types of solenoid valves do have different characteristics, such as response time, damping, spring rate and so on.

The turbo will respond quite differently if you rev it in neutral compared to working it under load, on the road. I think your best bet is to do what you've already decided to do, go an have a power test, which I presume will be on a dyno, which puts a load onto the engine exactly like running on the road. Tell them of your misgivings and they should be able to see exactly what is happening.

At the moment I think it is possible that the replacement turbo was maybe a part for a slightly different engine, from an Audi or a Skoda perhaps. If this does prove to be the case then it may be affected by the engine map expecting the OEM fit turbo. A custom remap would sort this out, as the map would be made to suit the components in place on the car...

I don't think a new N75 is a good idea, at least not at this stage. I would wait until we can find out what the new turbo is and if the N75 was changed at the same time.

On a separate note, do you know if the inlet manifold was cleaned out when the EGR blanking plate was put on? I hope so - one of the points of doing this job is to stop the formation of horrible sticky and burned sludge downstream of the EGR valve, which otherwise eventually blocks the inlet manifold. It's the combinaton of hot sooty exhaust gas and the oil mist in the inlet charge from the PCV system.

 

[Israar]

Yes, looks the same as mine just gone over the picture of the N75 on mine and it has the same part # I just couldn't tell what it was at first as the first 3 parts 8E0 looks scuffed and until you pointed out that link I didn't get the part #

The paperwork concerning the turbo is jut as receipt with a brief description of the work done, which is half ass'd. Says

[B][U]Sales[/U][/B]                     [B][U]Quantity[/U][/B]      [B][U]Rate[/U][/B]        [B][U]Net[/U][/B]
supply & fit turbo euro     1.00        620.00      620.00
oil and filter

If you want a picture I'll send you one if you like? I've wrote on it the Head Mechanic who did the work on my car, he did the EGR blanking and he also did the turbo replacement. I rang him yesterday as I wanted to find out about a remap and the company I rang stated unless it was a genuine OEM replacement they wouldn't touch it. So when I rang him I asked him he could tell me if it was genuine OEM or remanufactured, he got it up on the computer (as it was done in feb) and said that it doesn't tell him much about the turbo though he mumbled something about my old turbo and he had to dig around. So I said to him that he said he always works with brand new turbos and goes with the likes of ITS Turbos, as to which he said yes he does but if I recall correctly he didn't go with them. Something about having an issue with them and my turbo, he said he told me about it and I said I haven't spoken to him unless he spoke to one of my family members who was keeping the car while the work was being done as it was done up Manchester while I'm working and living down in the West Midlands since my turbo needed replacing while I was up there

So I don't have any information on the turbo itself, I can ring him tomorrow to try and find out exactly what turbo was used, where he got it from and to see if he changed the N75 valve (as this might have been the trouble he was on about if the N75 valve was on before he changed the turbo). What information would I need exactly, anything specific?

Sorry, I mustn't have said that correctly, the only pipe unconnected is the one I mentioned which is the one connected to the t-line in the atmosphere connection going to the air filter. I'll have to find a decent plug or so to plug that specific pipe though

Not sure if you got it from the way I described about the pipe being disconnected on mine, so if you did sorry if this bit means nothing to you, the pipe that is going in the to N75 where arrow 5 is, then travels back to the t-line, that is the pipe I'm on about that isn't connected, although as you know, the atmosphere line there is free to be connected whereas on mine it's got that block. So I've not got the genuine OEM N75 on mine, as you found out for me

Definitely booking in for a Rolling Road power test, as I want to make sure it's doing what it's supposed to and see where I am with the car and it's power. I had a feeling revving idle at road side was different than driving and revving, but wasn't entirely sure on why or how, more to do with force possibly and load or?

Yeah, I was told if it's not an OEM replacement then the VNT mechanism would be setup differently to what the car is expecting (ECU) and would cause problems for a remap, which requires more time to sort out, this is from a remapping company that stays away from hybrid and remanufactured turbos. (Might sound silly but reconditioned and remanufactured are technically the same thing right?)

In time I want to go the route of custom stage 1, though money isn't grand for that kind of work right now though... How would I go about finding information on the turbo if the mechanic doesn't have the information? Would I have to be under the car to find the turbo identification plate (given it has one), I can state that the mechanic did state to me and reassured that it's under a 12 month warranty as he asked if I had any problems I basically said to him I'm not sure but I just want to know what's in the car.

Yeah, definitely a good choice considering the way the N75 is at present in mine and the N75 is how it's supposed to be in the Audi's, albeit it's making me feel more and more lost as to what the hell has been going on with the car now.

I'm not 100% sure, but when he blanked off my EGR valve I believe he said he gave both the manifold and the EGR valve a full clean. If he hasn't and has put on a new turbo with the manifold not being cleaned, what am I to expect in results of problems? Would it be a serious problem or a in the future type of problem?

Thank you so much for your help mate, I can't thank you enough for your efforts in help me out with this, once I'm sorted out properly I'll have to take you for a drink or something in return for your kindness and time!

--Lee

 

[Muttley]

It's a shame that the receipt doesn't give any details, but it was a long shot in any case...

I would hope the Head Mechanic can give you the details we're missing. He may need you to tell him that you only want to find out what has been fitted so you can work out what to tell the mappers, not that you are criticising him or blaming him...

As far as OEM replacement, we are probably in a grey area, as it looks like it might be a correct replacement for a VAG 1.9 TDI engine, just not for one coded ASV. There are an awful lot of 1.9 TDI's around.

What you would like to get from him is mainly whether he changed the N75 together with the turbo. The type of turbo and the engine types it was OEM for would be a great help too. That is the sort of info the mappers will need to determine a start point for your new map, otherwise they will have to start from something very conservative and take a lot longer to get to a good result.

Thanks for confirming that there is only the one unconnected pipe. I think we now know for sure that it was connected to the atmo side of the original N75. So it goes to the air filter, and the N18 valve, and it's not causing any boost leak problems. To be tidy, I'd put a bung in it (most people seem to use a suitably sized screw).

Revving the engine in neutral is of limited value, because the ECU takes in road speed info as well as accelerator pedal position, mass air flow, and lots of other stuff (listed in the little diagram on the lower left of my vacuum system diagram). With no load it will just increase the injection quantity a tiny amount to increase the revs, but the output power will be almost unchanged. A rolling road, or dynamometer, has brakes on the rollers so as to put a proper load on the driving wheels.

Reconditioned and remanufactured are indeed essentially the same thing, though remanufacturers would claim that they do more than just recondition: But basically both take a worn turbo and replace parts (seals, maybe turbine and impeller sections, possibly other things) to bring it back to original spec performance.

If the mechanic can't find anything about the turbo, tell him that you do have some problems, erratic turbo performance, poor power delivery and so on. The turbo may have an identifying plate on it somewhere, but it will be difficult to see as it is tucked up behind the engine. A torch, a mirror, long arms and some luck will all be useful. Hopefully you can get it up on a lift? If not, axle stands and chocks under the wheels, you will be completely under the car and the last thing we want is for it to fall on you

Re: the inlet manifold - as I sort of said earlier, the way EGR was implemented on the 1.9 TDI was as a fix to modify the engine to cope with changed enviromental control regulations from California (and hence, very quickly, the US market) that demanded better control of Nitrogen oxides, NOx. Diesels produce more NOx than petrols because they are more efficient (oh, the irony) and reach a higher peak combustion temperature than petrol engines do. EGR (hack, spit: I dislike EGR, does it show?) decreases the efficiency of the engine by reducing the oxygen content of the inlet charge... by making the engine breathe its own exhaust. As an engineer, I find that one of the most horrible quick-fixes ever perpetrated in the name of environmental protection. (I can go on for ages about the wrong-headedness of Californian environmetal regs and their real effects)

Er, I've become sidetracked... anyway, EGR on the 1.9 TDI will slowly block the inlet pipework. Does not affect the turbo as such. What usually happens is that the EGR valve sticks open after this has been going on for some time, which results in overboost and limp mode. (I can explain why, but that would involve more diversions...)

One of the best fixes for this is the EGR blanking plate, so you will not suffer from that problem. But if the inlet pipes weren't cleaned then the inlet would still be choked and you'd not get the performance you expect (as the engine can't get enough air).



Hey, don't worry too much about my time, this is like an engineering detective story, meat and drink to me That said, I do like good beer....
And if anyone needs an engineering project manager, I'm currently available, CV will be sent given the slightest sign of interest

 

[Israar]

Well, at least that was one more thing eliminated in one sense hehe!

I'll just have to ring him later after I've had a sleep and ask him for what we need to help us sort it out. I'll definitely let him know before hand that I'm only after information regarding the current turbo he fitted, what this so called problem he told me about which most likely was stated to one of my family members if not he never said anything haha! There are definitely a lot of 1.9 TDI's about, just not very much information out for the ASV engine

I can safely say I believe that he had to change it because no one touched my engine before I had the EGR blanked off, which is when I had major problems with power before being told about my turbo. Here's a video I recorded up Manchester before it went in (maybe a few days before it went in for the EGR blanking) and as you can see if you go further in to the video (excuse my EXTREMELY poor recording skills) you can see that the N75 I had originally in was hooked up to the pipe that is currently disconnected, so they DEFINITELY changed my N75 valve!

Seat Leon 1.9TDi SE 110 - Engine Recording

No worries mate, I'm hoping to give as much useful information as I can without bogging down too much with wasteful information, hopefully nothing so far has been wasteful Later on I'll put a screw in as I have a few in the cupboard and I'll cable tie it in also that way it's extra sealed.

See, I never knew that myself, though I know to get a proper power test reading you need to dyno the car, which is one thing I'll be having done very shortly!

Well at least my hunch was right in a way, I'm hoping that when I ring the Head Mechanic later he can tell me everything I need to know and hopefully not be funny about it, although to save him feeling like I'm probing him to screw him over I'll make sure to take you up on your word about why I want this information

Yeah, definitely don't want a car falling on me, I'm strong but not that strong! I don't have any lifting equipment yet, such as axel stands and so on, as I've not yet invested in them nor had the money to. As for getting it up on a lift, it'll cost me so I'll have to wait to try and self check this turbo of mine, saying that, I'm due to go up Manchester in just under 2 weeks, so I can always borrow my cousins axel stands and try to check it there maybe, unless I get what I need from the Mechanic beforehand (later on today! )

Haha, you will have to enlighten me on your dislike for EGR and the regulations as to why they got brought in concerning California, as I've not the slightest clue as to why it was ever introduced. Not sure if you know but I've only known about Diesels to what I know of now since becoming a member here and I've only had a Diesel engine myself the past year. So it goes to show for me I'm a complete novice to them, though on the learning bandwagon

Well we can discuss that at another time, something for me to learn and also something for you to vent on hehe!

I'll double check with the Mechanic though to make sure the manifold was also cleaned, if not I'm going to have to get that cleaned too, though for how to clean it, I ain't got the slightest idea!

Haha, well if you're OK then that's great and I'm glad you seem to be enjoying the trials with me, as much as I'm still learning and want to fix the problem at hand, I am thoroughly enjoying learning about it! I can say I've never been so much interested in a car or engine, etc. I've took small interests but never to the point where I'm physically going out my way to want to know more haha! I am actually loving it to say it outright!

Haha, meat and drink to you, I like that! Well if you fancy it when money permits for me and I'm sorted more with the car, I can always come pay a visit and treat you for all your help as a gesture of gratitude, whether it be a good beer or food and beer involving a good ol' chat, I like long drives so that's one thing that wouldn't ever bother me

Hmm, I don't think I know of any engineering jobs though I will definitely keep my eyes posted, though don't know whether you'd come up this way for work like? I'll definitely keep my eyes peeled

Thanks again Muttley, time to sleep and rest then do some digging tomorrow haha!

--Lee

 

[Israar]

Sorry this is a late update, small for now but at least the ball is rolling!

Turbo that was taken off was the same turbo but all new parts according to the Mechanic, he said he can't get up what brand, part number, etc... From his receipt, he needs to get in touch with the supplier then will get back to me on Monday with the information.

As for the N75, he said he did change it, when they was blanking the EGR valve off they swapped the N75 with one he had available as he was checking to see if it made a difference, something about eliminating the N75 from the original trouble I had with the engine chocking. He himself said he hates the invention of the EGR valve in total, so he might share a similar mindset to you on the EGR system Though he must have left this one on and not put the original one I had on since the problem with the engine chocking went with the EGR being plated.

So, from what I gather I don't have my original N75 but the turbo that was taken off mine should be the same as what was on it but with new internals. Though as I said, until Monday (at least I hope he can get back to me by then like he said he will) I'll have to wait on the information about the turbo itself.

I explained about what I wanted the information for and he asked where I was considering to get my remaps done, he did also mention that if he can't get the information for Monday (as I told him I would be up Manchester not next weekend but the weekend after to see family) then if I pop in to see him when I'm up he will happily put it up on the lifter for me and get the information I need so that was nice of him

--Lee

 

[Muttley]

Good news he *did* change the N75, so we know it isn't the original, and by his own admission, "one he had available" so not necessarily one with the same spec as the one that was removed... which may have an effect on the engines response.

Engine choking sounds like symptoms of carbonised deposit building up in the inlet.

Sounds as though you have a rebuilt turbo, which should be fine.

 

[Israar]

Yeah which is nice that he stated it as I found the video recording I made before it went in for the EGR blanking, back when the engine was chocking itself, on that video the original N75 was there and the unconnected pipe was connected to the N75

Trouble is, how would I now find out the original N75? I don't have engine chocking any more, I had it before the EGR was taken off, cleaned and blanked, running wise and ticking over the car seems to be in good nick, though the response from the turbo itself isn't what it was but it's there

When I get it on it's power run, I'm safe to hazard a guess it won't be nice and neat the graph that will show up haha?

With knowing about the N75 now, would you say it's worth while trying to get a new OEM N75 valve to test against the current one?

--Lee

 

[Muttley]

I think it is probably best for now if you wait until you have the results of the dyno run, and maybe some advice from the guys running the dyno. It is a bit odd that the mechanic changed the N75 but didn't change it back.


EGR is solely there to reduce NOx. It does this by reducing the peak combustion temperature, how hot it gets when the charge is burned in the cylinder. Under some circumstances (medium revs, high load) the charge gets hot enough to burn the nitrogen in the air into nitrogen oxides, NOx. The method used, rebreathing exhaust gas (which is relatively inert, although in a diesel there will still be some oxygen in it), is extremely unpleasent and contributes to major problems as the engine gets older, clogging the inlet manifold and the valve eventually sticks open to cause limp mode.

I'm not convinced by the arguments about NOx, as there is considerable research showing that reducing NOx while increasing CO and soot production (which is what the EGR does, as well as reducing efficiency) has an overall negative impact on the environment.

NOx is demonised as a smog precursor, but having looked at the evidence (and there are a lot of environmentalists who share these doubts) I think that targetting NOx in isolation is pointless, as it is the interaction of NOx with other smog factors, e.g. unburned hydrocarbons and particulates that causes smog, and reducing one while increasing the other is no help at all.

California comes in for criticism because it is the most smog-ridden state (that's what happens if you build a city in a place the locals called "valley of bad air") and is also full of pea-green Californicans. They have the most strict environmental regulations in the US, which tends to drive US national regulations and so influences European standards and manufacturers (who want to sell lots of cars to Americans).

 

[Israar]

Okipoki will do mate, yeah I thought so too when I asked him, no update as of yet so chances are I won't find out until I go up there next week.

Now that I would have never known without you telling me, then again unless you look properly at things you never fully understand it just by looking at the cover (Concerning the comment about the Californian people and the environmental regulations.) I never thought they where the ones influencing the standards either!

Yeah, I have to agree with you there, taking one thing away from a cluster of bad things while increasing the others is not going to make anything much better, if at all.

Will be ordering some new tyres as I need some and they'd benefit me being done before the dyno so hopefully I can get them on with swift speed!

--Lee