N75 - boost leak/ maf HELP PLEASE

[mexicovrs]

Skoda 53 plate 150,000 miles full service history and look after.  About 12 months ago ECU light came on and was scanned by local specialist advised incorrect flow detected secondary air system.  I know the pump needs removing and bolted together again but ain't got round to it yet.  But I have lost all power from the turbo.  Used to get a nice sound and a kick in the back when I put my foot down now nothing at all, runs like normal 1.8 petrol motor.  Changed the hockey puck and diverter valve  oem stock parts from TPS. Carried out a new PCV valve under manifold as it was caked in dirt and oil.  This made the car run much better and less oil loss due to reduced crank case pressure.  The crank case pressure is still quite hight again and the performance is down.

 I have a very limited funds but would like to get the car back to normal performance with the turbo working. Be really grateful for some advise or anyone near Northamptonshire who could help even locate the problem in exchange for a few beers.  Perhaps offer to scan the car and clear the code logged etc..Happy to get my hands dirty and learn but need some guidenace of where to go next. 

 

  

 

 

[mexicovrs]

Some of the parts replaced !! Together with valve locations under the metal plate adjacent to the manifold.  Wondering if one of these valves might be responsible for no turbo ????anyone ????genuine diverter new pcv valve and elbow joint below the manifold.pcv valves under metal plate any help idetiyfying these please ! How to test or clean ??new hockey puk

[kennedy]

I lost my clip and the plug came out of the N75 valve and I lost all power from the turbo. Could be that or yours is broken 

 

[mexicovrs]

Hi Kennedy 

 

No the clip is still intact and connected so I guess the n75 is knackered but don't really want to replace if I can avoid it.  Can they be cleaned ?? Happy to purchase one but not for £68

quid from local dealer. Does anyone have any other recomendations for oem part !! 

[Silver Bullet]

 

Quote

Can they be cleaned ??

Yes, indeed they can be cleaned :-

Remove N75, and using suitable carb cleaner aerosol with nozzle attached carefully spray into hose spigot, put finger over end and shake, allow liquid to drain away.

Repeat for remaining spigots and allow to dry. I cleaned mine a month ago with nothing coming out. I have a Oil Catch Can fitted so really didnt expect to see any oil contamination,

I was just curious to see if there was anything.

If you fit a Oil Catch Can (plenty of how to's on here), it will vertually eliminate all oil residue (sludge) in the turbo charge pipes, components and crankcase breather piping,

 

Another big plus about fitting one is you will get a cleaner combustion burn (not having to burn off all the oily vapour from the sump and cylinder head). Our engines run on a closed system, nothing vents to atmosphere.

Edited 30 August, 2017 by Silver Bullet

[mexicovrs]

Thanks for the cleaning tip I will give it a go at the weekend got to be cheaper than a new valve !!!  I guess the same would apply to the valves under the manifold n249 etc.... oil catchcan sounds great but would prefer to keep the car as stock as possible, not keen on modifications happy the way the car was running before the lack of turbo so just hoping to get that back. Thanks for your advice lets hope it works although I think  new valve might be in order with 150 k on the clock.  

[Silver Bullet]

I understand your reluctance to do any "mods" , but I guarantee you if you take one of the smaller hoses off and look in them they will be partially clogged with sludge.

The standard hose bore diameter is about 6 mm, the blue fluro-lined silicone ones ive fitted for the OCC are 19mm bore. (fitted in Oct 2010, I bought the car in 2006).

As you say with 150k on the clock maybe replace but give it a clean first and see if things improve, also it wouldnt do any harm in checking and cleaning all the other components.

 

Good Luck

[mexicovrs]

Thanks for the advice will make a start on cleaning the valves see how it goes.  Was going to try cleaning the maf too but those friggin security hex screws What a pain in the arse !!!!!  Still having found the right tool to get them off..

 

Do you know what size silicone tubing I would need to buy to replace all the vac lines for the valves and how much would I need? Do I use jubilee clips or cable ties as they are quite small.  I would assume jubilee clips as likely to make a better seal.  

[Silver Bullet]

Hi,

Regading the MAF high security screws you can buy a set of security bits from these people : http://www.vehicle-wiring-products.eu/  (part Number :Ref 2267). Its 33 piece set on 1/4 hex drive.

I have used them for years and they have never let me down,

 

Silicone tubing size, sorry dont know, you will have to drag a pipe off and measure it, (try to get fluro lined silicone as the vapour will attack the silicone tube walls eventually. (I have bought all my tubing from Forge Motorsport, not the cheapest but good quality (there are other good suppliers out there now so its worth shopping around).

How much do you need?, get some string measure all the lengths you want to replace and total up + a bit for ** ups.

 

Regarding pipe clips, Personally I wouldnt use cable ties, nylon does not handle high temps well and absorbs moisture, degrades over time and can eventually let go.

(When I fitted a Forge Turbo Inlet Pipe I used a nylon elbow  to connect a smaller pipe thats near the MAF. It literally fell apart when I was checking all connections. Luckily ii was able to get ever piece out, If you look at the elbow near the PCV valve its made from glass filled polycarbonate. All plastic high temp areas on a car engine tend to be made of that material.

Try to use stainless hose clamps, dont over tighten or you can crush the spigot, go round about a week after fitting and give the clips a slight tweak up as they bed in.

 

NB:Ref: Kennedys pic, can you see the top hose ( Y shaped, one end comes from cam cover), they tend to split, squeeze it, you mightl find its very soft, consider replacing that one as well with fluro-lined

pipe.

 

Good Luck

 

 

Edited 31 August, 2017 by Silver Bullet

[Silver Bullet]

Hi again,

going through all the parts I removed when fitting the OCC I found these 2 hoses I bought from AwesomeGTI years ago. One is the upper hose mentioned in the above reply and the second one (also prone to failure) goes from pcv to underside of inlet manifold, They were only on the car for a couple  of months  Both are silicone fluro lined (Forge ones are £74 for the pair) you can have them for £30 if not they will go back into my filing cabinet. Let me know.

 

 

Peter

Edited 31 August, 2017 by Silver Bullet

[mexicovrs]

Thanks for the offer!  I replaced the Y hose (breather) with part from TPS  and bought a silicone one from creation motorsport  for the underside of the manifold with new pcv valve as pictured so all that has been done about 10 months ago replaced a number of hose clips with s steel jubilee ones as the picture shows to ensure no leaks I will check again all the hoses At the weekend and get back to you on this might take you up on your offer.  Have you done the whole PCV delete them without performance issues  !!!!

[Silver Bullet]

Hi,

Im glad you have replaced those 2 pipes, to be honest I dont see reason to replace them again if they are made of silicone.

Yes, I did the PCV delete, together with other improvements, the engine breathes better, pick up is still sharp, at 2.5k rpm the turbo kicks in and still throws you back in the seat.. Oh yes, few months ago I took the "puck" out it, was clean inside no oil residue on the walls.

The link below is a bit of historical data for you to look at, it should make interesting reading.

https://www.briskoda.net/forums/topic/319645-what-do-i-need-breather-hoses-under-inlet-manifold/?tab=comments#comment-3832238

Good Luck

 

 

[mexicovrs]

Thanks again for all your help i will have a good look round and clean on Saturday and report back ? Could I also be looking at faulty boost pressure sensor in the throttle body to intercooler pipe? Although cleaned the throttle body when I did all the pcv work/ and it was very clean. Could it be a stuck Wastegate actuator.  Can I do a leak test on the pipes with soapy water and the car running or do I need to do a pressure test if so what do I need and how to do it would be helpful.  

[Leeboy]

All good advice here,  one thing I would look at if I was you would be the rigid plastic elbow from the crank case breather thingy that your silicone replacement pipe attaches to.   This is how mine looked on an engine that had done just under 130 thou miles when I bought my current vrs.  despite cleaning out the gunk, I ended up replacing it as the ply had gone brittle. 

 

[Silver Bullet]

Hi,

your very welcome, I joined in 2007 and since then, on a steep learning curve (like yourself) regarding turbo engine ownership. .

It would help you pin the problem down if you could get someone with VAG-Com to do a diagnostic scan for you and clear any stored errors, they can have a knock on effect

and create more errors. Your above check suggestions are good ie wastgate sticking or a faulty boost pressure sensor, all are possible,

 

If it was my car (you say you have no boost at all), I would first check every hose (from the turbo outlet through to the throttle body) ensuring all are secured and tight,

On the drivers side at the back of the engine the stainless boost pipe turns at 90deg towards the ground, A rubber hose with a rubbish seal  pushes into the end and

is held in with a clip that locates on 2 barbs to hold it all together. This is covered by a flexable heatshield that clips together (2 pop buttons) This rubber hose can become disconnected,

and you wouldnt know as the h/shield covers it all up.

 

As a matter of course I replaced all the crap wire hose clips with jubilee ones. Soapy water is good enough to show any air escaping, if its that bad you should hear a hissing sound.

Finally, why not start a check list of all the things you have looked at, it might help you track it down by simple elimination and help you to zero in on the problem area.

Keep me in the loop as im curious as to whats causing your problem.

[mexicovrs]

Hi leeboy

 

Thanks for the input, mine was the same when I replaced it about 10 months ago so this should all be ok now.  Pig of a job !!!!! But glad I did it. 

Edited 31 August, 2017 by mexicovrs

[Silver Bullet]

You seem to have started firing off posts that are connected to this original one, (not a good idea as information could be lost if anyone does a search and only finds this one)

Anyway, final suggestion from me.

If you havnt done so already, pull off the TIP (can be done from above), you will see the turbo impeller, give it a flick with a clean finger, it should spin freely with minimum

or zero end float. If it doesnt spin, a fin might have come off and jammed it or something has got in and is jamming it. I hope this isnt the case but its worth checking for peace of miind.

[mexicovrs]

So after 4 days of smooth idle driving and smooth power delivery my dreaded engine management light decided to flash up and stay on again despite all hoses checked and new MAF.  I know this is a stored code as I don't have the facility to clear it down so guess it's comes back after a short time.  Still no turbo boost between 1800 and 3000 rpm still no sound of spoiling up etc so totally stumped here people.  Going to check the actuator on the wastegate isn't stuck so what should I be looking for I don't have a compressor and don't really want to blow air down it to see it it moves as if the diaphragm goes I ain't the got the funds to fix it.  Can I just spray some WD40 and work it free if stuck.  Best methods please. 

[mexicovrs]

The saga of low boost pressure continues at least now i have done a scan and had the following errors.

 

 

4 Faults Found:
16795 - Secondary Air Injection System 
            P0411 - 35-00 - Incorrect Flow Detected
17964 - Charge Pressure Control 
            P1556 - 35-10 - Negative Deviation - Intermittent
16486 - Mass Air Flow Sensor (G70) 
            P0102 - 35-10 - Signal too Low - Intermittent
18010 - Power Supply Terminal 30 
            P1602 - 35-10 - Voltage too Low - Intermittent
Readiness: 0000 0000

 

 

Which leads me to either the MAF bosch recon unit bought from ECP is not suitable for my car despite vw part number being the same and possibly faulty N75 valve despite cleaning it out.  I know that the secondary air pump needs fixing but that shouldnt cause a boost pressure issue so a new MAF from tps and oem n75 needed is perhaps the next route.

 

Anyone know which blocks on vdcs lite I need to messure for n75 testing amd what values I  need to look for.    Standard car with no mods

 

 

 

 

[Silver Bullet]

More info on your error codes above:-

 

http://wiki.ross-tech.com/wiki/index.php?title=Category:Fault_Codes&pagefrom=16503%2FP0119#mw-pages

[mexicovrs]

Thanks for this most helpful, already checked rosstech wiki for these codes.  So aware of what i need to look at.  Pretty ****ed about the MAF not working on 4 days old !!!!

[mexicovrs]

For anyone with Vscope know how.  Just done data log of boost pressures requested v actual and there is a huge difference which leads me to suspect the wastegate is not opening at all.  can anyone shed any light on this log for me by looking at it as to what the issue might be.

LOG-01-021-323-115C.CSV

[mexicovrs]

just to add can someone convert this to excel and repost for me please ???    so its clearer to understand in graph form!!!!  did another scan for error codes and only code was 17964 - Charge Pressure Control 
            P1556 - 35-10 - Negative Deviation - Intermittent

 

so same fault.  also the car didn't want to start first time this morning had to crank over for second time.  It was colder this morning than it has been so hoping this is not the start of a cold morning issue also.

 

Thanks

[LightRain]

File converted to XLSX.

It does indeed look like quite a discrepancy between specified and actual boost. As you say, wastegate maybe needs checking out.

LOG-01-021-323-115C.xlsx

[mexicovrs]

Thanks for the help on this.  Still puzzels me though.  Just tried cold starting the car this morning and revs up and down between 1000 3000 wouldnt settle to normal idle.  Turned off and restarted and settled down to just over 1000 rpm.  Constant no up and down hunting.  Any idea would be greatly appreciated.