Loss of power - Please Help :-)

[mk2ibizanewbie]

Hello all,


Looks like a great forum for all Seat owners alike... Hoping someone on here can help???


I have a MKII Ibiza TDI, AHU engine with 150,000 miles, owned from 130k and had no problems until now...


I recently experienced a lack of power, took to garage and they believed the MAF to be at fault. Replaced MAF for a Pierburg as advised these are more reliable but this has not solved the problem.


Trying to sort this myself as cannot afford more garage costs...


1)

I'd like advice on what I can do to diagnose the problem??? How can I establish if it is the turbo or not??? (did not experience any loss of oil or blue or black smoke, noticed others have mentioned this when turbo has gone)


Managed to get under the car earlier today and established that it is a Garrett turbo rather than the KKK.



2)

If it is the turbo, what options do I have for replacement??? Apart from the obvious like for like replacement. (Not sure of the exact Garrett turbo I have but think may be GT1544s, if anyone knows, please let me know)


Hopefully someone else on here has had a similar problem and could point me in the right direction.


Thanks in advance, all the best...


Steve

 

[Muttley]

Need more description of the symptoms. Whe does the lack of power become noticable, and in what way?

AHU is a 90 bhp TDI with a wastegate turbo, not VNT, so it isn't sticky vanes. My bet would be on sticking EGR valve, but it's a wild guess without more detail.

 

[GTV]

when you say loss of power, does it rev ok? when our Ibiza played it it would not rev pass 3k and this was the MAF, as said before the AHU is a wastegate turbo. Also when we got the Ibiza the turbo was blown then, you would know about it as was was using more oil than Diesel!

 

[mk2ibizanewbie]

Hello Muttley,


Thanks for the response


Not really sure what to say about the symptoms... Happy to answer any questions or try doing different things to help explain what's going on...


The lack of power is permanent, it's not just now and then, it seems that its just running as a diesel now without the turbo kicking in at all.


What can I can do to establish if it's a sticking EGR valve or not?


Not sure what it is or where it's located, any descriptions of where it is and what it looks like greatly appreciated.


Thanks again,


Steve

 

[mk2ibizanewbie]

Hello GTV,


Thanks for the response,


Yes it does seem to rev ok, as my response to Muttley it just seems to run as a standard diesel at the moment without the turbo kicking in at all...


It's not using any more oil than normal so hoping it's not an expensive turbo replacement...


You mention that your turbo was blown when you got your Ibiza, did you also have the Garrett turbo or was it the KKK one? What options did you have???


Any help with diagnosis or options for possible solutions really appreciated...


Thanks again,


Steve

 

[Muttley]

Permanent power loss I'd guess is caused by a sensor or actuator failure, causing the ECU to go into limp mode, protecting the engine.

Have you checked for a boost leak, a hose popped off between the turbo and inlet? Should be noticable as a hiss when the engines running and clouds of black smoke when you try to accelerate. You haven't mentioned this so I assume this isn't the problem.

Did you take it to a Seat dealer? If so they should have used diagnostic equipement to trace the fault, and can show you the printout. If not, post in the VAG-com section of the forum to see if there is someone near you who is willing to come out and help. VAG-com is third-party diagnostic software that can be used on a laptop with a suitable connecting cable to plug into the cars diagnostic port.

I'd be looking at the MAP sensor (boost pressure), N75 valve (wastegate control) or the wastegate actuator on the turbo. The wastegate is open by default, and if the control system has a failure then it stays open and you get no boost.

But again this is guesswork, and you need to get some diagnostics run, really.

 

[GTV]

As, with ours I got a second hand turbo of another ahu so I don't know what it was, the AGR on this engine is under the engine cover at the back of the engine, once you have removed the cover look at the rear mounting bolt for it and there is is, you will see the small vac hose coming out of it on the lft if that makes any sence.
As said above I believe the wastegate actuator can course problems and that would shut off the turbo but best this is to get it on Vag com and see if you have any fault codes logged.

 

[sssstew]

yeah agreed with mutleys last post. You could always try to swap the N18 and N75 valves on the back firewall to see if that restores the power. Could rule out a dodgy EGR or Boost valve.

 

[mk2ibizanewbie]

Hello again Muttley and thanks for the continued support with this...


As for the boost leak, something popped off, think we can rule this out as you've said, I've no smoke and cannot hear any hissing etc.


No, I did not take it to a Seat dealer as my nearest one was 45 mins - 1hr away, took it to a local garage that specialises in fast turbos, Cossies, RS turbos etc, thinking that if anyone could sort it they could...


How wrong was I, they told me it was showing a code/fault for the MAF and that this was probably why I had no power, then they informed me they couldn't really help further as they didn't do diesels... (Got the impression they didn't want to help)...


So I bought a new Pierburg MAF and replaced it myself, hoping this would solve the problem, but alas it hasn't, so here I am trying to get some help/knowledge from you guys/girls on here...


As for the MAP sensor, N75 valve, wastegate actuator or sticking EGR valve etc...

Q's)

Are these all connected to the turbo? (I assume so)

Would it be best then to try and remove the turbo and all these components so I can clean etc. and then try to look at whats going on?


Re: Diagnostics...

I have a laptop and I've seen cables on ebay that claim to be able to connect your car to a laptop; Is VAG.Com software available for download?

My thinking here is that whilst I could post on here for someone to come out and help me, I'd feel obliged to pay them for their time (unfortunately I'm pretty skint at the moment), plus if I had this cable and software I could use again and again and again etc.


Please let me know what you think and thanks once again for your continued support...


Many thanks,


Steve

 

[mk2ibizanewbie]

Hello again GTV, thanks for trying to help with this...


Thanks for your description of the AGR did you mean EGR or is it actually AGR? (bit confused)

I will try to look at everything people have suggested later this evening and report back a.s.a.p.


What do you think about me trying to remove these bits, cleaning etc and then trying to see whats going on as my response to Muttley???


Have you any experience of removing these bits etc? Perhaps It's hard to do and I'm being a bit naieve?


Also do you think it would be sensible to try and get a cable and get my own VAG.com etc?


Many thanks,


Steve

 

[mk2ibizanewbie]

Hello sssstew,


thanks for trying to assist me with this...


Seems like an excellent suggestion trying to swap the N18 and N75 valves (if only I knew what they were) time to do some googling and try to get some pics etc to see what you're talking about.


Once I've established what they are and where they are located, could you advise how difficult this would be to do, or is it just a case of unbolting, switching, rebolting etc?


Also if you have any other comments on my responses to Muttley or GTV, or other suggestions/advice I'd be extremely grateful.


Thanks again,


Steve

 

[Muttley]

Failed MAF is not usually a cause of permanent power loss to the extent you describe. Although it's hard to tell at this distance. The usual test of a MAF is to unplug it and drive a short distance. If it performs better with the MAF unplugged, it should be replaced.

VAG-com is a product of Ross-Tech

You need the software and a suitable lead: there is a dongle in the car end of the lead

The pukka Ross-Tech kit is $250 all-in, includes lead and software license.

Cheaper leads can be bought on Ebay, and used with the downloadable free shareware version from Ross-Tech. This is limited in functionality, will not read all fault codes and will not allow any resetting of vehicle parameters. This last is a major benefit of VAG-com, for instance it allows the EGR to be reset to a minimum value, preventing the otherwise inevitable choking up of the inlet manifold.

(Brief aside: Crankcase gases are fed back into the inlet system downstream of the MAF and air filter to comply with environmental legislation. Crankcase gases carry oil vapour, and the inlet system is therefore well oiled. Farther downstream, past the turbo and next to the cylinder head, there is an Exhaust Gas Recirculation (EGR) valve, controlled by the ECU, allowing some exhaust gas (inert, all the oxygen has been combusted) back into the inlet for! environmental! reasons! - yes, it is to reduce the formation of NOx, nitrogen oxides. Exhaust gas is hot and sooty. This combines with the oily crankcase vapour to form a sludge which gets baked on to the inlet manifold, eventually choking it up. I have my EGR disconnected, but some later engines won't let you do this)

However, to start with, an Ebay lead and the shareware version will get you started. If you want to activate the software later, you'll need to buy a license, $99 I think.


Here's an annotated underbonnet view of a TDI 110 that I have used in several threads now (although it isn't original to me, and I can't remember who I copied it from now). Most of the component locations are listed.

For completeness, I should add that the sensor assembly in the pipe from the intercooler at 12, labelled IAT (Inlet air temperature) also houses the MAP (manifold air pressure) sensor (NOT to be confused with the MAF - Manifold air Flow sensor, which is labelled 4) This makes sense, as you want to know the temperature and pressure of the charge going to the cylinders, after the intercooler.

MAP is manifold air pressure, measures the pressure of the charge going into the cylinders.
N75 is the boost controller, a solenoid valve that varies the pressure applied to the wastegate actuator. The actuator is worked by air pressure rather than an electric motor, I assume because it gets pretty hot down there.
The EGR valve is also worked by pneumatics, and the N18 valve is the control element. I had a go at explaining EGR above. I can bore for England on the subject, don't get me started

The wastegate actuator is on the turbo itself, underneath the car. A little drum with a vacuum hose going into it and a rod coming out the other side attached to a crank on the turbo. With the engine off you can try moving the rod to see if it is free or sticking. If you observe the actuator as the engine is switched on (Carefully! on ramps or using a mirror or something!) you should see it move to close the wastegate.

I don't think you're quite at the point of needing to remove the turbo yet.

However with the mileage on that engine, there is every chance that the inlet side has choked up and the sludge has built up on the EGR, maybe sticking it open permanently. There's no easy way to tell that short of taking it off.

At the top of this section you'll find a sticky thread labelled "TDI 110 vacuum system and other diagrams". This may help to explain some of the terms used in this thread. Bear in mind that I diagrammed an ASV engine: your AHU will have some differences.

 

[GTV]

Hello again GTV, thanks for trying to help with this...


Thanks for your description of the AGR did you mean EGR or is it actually AGR? (bit confused)

I will try to look at everything people have suggested later this evening and report back a.s.a.p.


What do you think about me trying to remove these bits, cleaning etc and then trying to see whats going on as my response to Muttley???


Have you any experience of removing these bits etc? Perhaps It's hard to do and I'm being a bit naieve?


Also do you think it would be sensible to try and get a cable and get my own VAG.com etc?


Many thanks,


Steve

Sorry my bad I might the EGR, its not hard to remove a couple of allen bolts and remove the vac hose and off it comes, I have yet to remove mine but it is on my list of things to do as my engine has done 145k and the Ibiza has done 190k.
The AHU engine looks almost the same as the 110bhp shown above but its not a mirror copy.
Where are you based? there might be a member near you that can help with the fault codes. I have an Ebay VAG-com lead and it came with a full copy of the software not the shareware that is easy to get hold of.

 

[sssstew]

Hello sssstew,


thanks for trying to assist me with this...


Seems like an excellent suggestion trying to swap the N18 and N75 valves (if only I knew what they were) time to do some googling and try to get some pics etc to see what you're talking about.


Once I've established what they are and where they are located, could you advise how difficult this would be to do, or is it just a case of unbolting, switching, rebolting etc?


Also if you have any other comments on my responses to Muttley or GTV, or other suggestions/advice I'd be extremely grateful.


Thanks again,


Steve

Its easy to swap over, just be careful when pulling off the old hard vacuum pipes to not break the plastic pipes they slide over. So they are on the back right of the firewall in the engine bay, carefully pull off the pipes from each one (theres three on each from memory) and the elec connector at the bottom remembering to label each one, now unbolt from the firewall, swap around and reconnect.

This procedure helped me identify that i had a dodgy N18 EGR control valve causing my stuttering turbo but it might help you in this case identify of either the N18 or N75 are at fault.

On the other stuff... both are on the money