Newbie - Help needed, got boost issues with my LCR

[JBRADY95]

The turbo would not do anything to get those codes. They are specific to the heater control for the sensors but please check this on Gendan and Ross's sites.

I think you have 2 separate issues and looking for a common solution.

Have you checked the air filter is not blocked and checked the turbo wheels for excessive play, any smoke from the exhaust, unusual smell from the exhaust (fish is usually someone having fun), blocked exhaust (failed Cat)? Again a smoke tester can check for such a block.

Yes i think maybe 2 seperate problems but maybe one problem being caused by the other. It has an open induction kit thing on it, cheap filter which ill sort out when its running right, ill try another filter though see if it makes a difference.

No smoke or smells no...but was going to remove the turbo and check it over this weekend for any play or wastegate issues

 

[JBRADY95]

Stripped off TIP today and too boost pipe etc to get to the turbo a bit better. Put some pressure on to the actuator pipe and it all opens and closes as it should, it opens at around 5psi though if that’s correct or not?

Also checked for play in the turbo, there is some as to be expected but not a massive amount at all, better than I was expecting it to be.

Put it back together and checked it’s all correct etc, still no boost.

Was told to try pulling the pipe off the N75 valve that goes to the actuator and drive it and see, so I did that but still just vented all the boost out.

Urgh


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[verbal_kint]

I'd rule out simple things like leaks first, if you know the system is tight then you can work through everything else.

Have you got VCDS to do live data logging, that could show what is happening when you request boost.

 

[JBRADY95]

I'd rule out simple things like leaks first, if you know the system is tight then you can work through everything else.

Have you got VCDS to do live data logging, that could show what is happening when you request boost.

I’ve checked all the pipes etc, no leaks. No vac leaks or anything.

I’ve got an OBD scanner that goes to my phone and provides live data and all it’s showing is -14.7psi, with my vw I’ve also got, it reads that boost fine live etc so whether the ecu isn’t reading the boost in the leon and thats causing it or what?
It goes from vacuum to 0 so somethings happening but soon as it hits 0 it just vents out


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[JBRADY95]

Still stuck?!

 

[JBRADY95]

Cracked wastegate is something else ive been told could be a cause and is common on these?

 

[JBRADY95]

Got it boosting to 0.4 bar tonight which is the actuator pressure I believe? I pulled the pipe off the N75....consistently boosting in all gears at 0.4 bar, I put the n75 back on, and it went flat, it then spiked up to over 1.0 bar for a second then I had to lift due to end of the road, turned round, booted it and flat again....
Also noticed when booting it the temp gauge goes down then when I come to a stand still it goes back up to 90 again? Could it be an ecu issue causing all this?


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[DorsetChap]

If you could borrow and plumb in a manual boost controller (leaving the N75 electrically connected and zip tied to anything) and you get boost then you'll know that the ECU is behaving but not getting expected readings from the MAP sensor or the N75 (I know you have already replaced them but sometimes replacements are faulty too). Of course you could just keep the MBC if it works! Another idea might be to 'borrow' the N75 from your Golf where you know its working.

 

[JBRADY95]

If you could borrow and plumb in a manual boost controller (leaving the N75 electrically connected and zip tied to anything) and you get boost then you'll know that the ECU is behaving but not getting expected readings from the MAP sensor or the N75 (I know you have already replaced them but sometimes replacements are faulty too). Of course you could just keep the MBC if it works! Another idea might be to 'borrow' the N75 from your Golf where you know its working.

My other car is a VW CC TDi haha not a 1.8t unfortunately.
But if I fit a MBC and it still doesn’t boost, what we thinking then? It’s very temperamental which makes me believe it’s electrical fault?


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[DorsetChap]

Oops! Read VW and thought Golf for some reason. If an MBC doesn't help then you won't be any nearer to discovering the cause, but they're on Ebay uk seller for £8.09 so may be worth a punt if you can't borrow one. If it works then you've narrowed down the cause (or fixed it if you can live without a plumbed in N75). I'm not normally a fan of replacing bits in the hope of a cure, but an MBC is relatively cheap and easy to try out.
Other causes that have since come to mind are checking that the N249 delete was done properly, and whether the N75 hoses are connected to the correct inlets / outlets. I can't recall what goes where on an N75 as I went to an EBC some time ago.

 

[JBRADY95]

Oops! Read VW and thought Golf for some reason. If an MBC doesn't help then you won't be any nearer to discovering the cause, but they're on Ebay uk seller for £8.09 so may be worth a punt if you can't borrow one. If it works then you've narrowed down the cause (or fixed it if you can live without a plumbed in N75). I'm not normally a fan of replacing bits in the hope of a cure, but an MBC is relatively cheap and easy to try out.

Other causes that have since come to mind are checking that the N249 delete was done properly, and whether the N75 hoses are connected to the correct inlets / outlets. I can't recall what goes where on an N75 as I went to an EBC some time ago.

Thank you. Ive checked and rechecked the n75 inlets and outlets and they’re right.
As for the N249, the valve is still plugged in but I’m unsure of where the pipes should be? What if I plumbed the n249 back in, could that do anything?


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[DorsetChap]

Dunno is the straight answer. Here's a link that explains how it should have been done together with forum responses discussing the merits of having / deleting the N249.
http://www.seatcupra.net/forums/showthread.php?t=349627

 

[JBRADY95]

Dunno is the straight answer. Here's a link that explains how it should have been done together with forum responses discussing the merits of having / deleting the N249.
http://www.seatcupra.net/forums/showthread.php?t=349627

Cheers! Just thinking if i plumb it back in, might be ecu related not recognising the N249 or whatever?

 

[DorsetChap]

N249 delete involves rerouting the plumbing (pipework) off of it but retaining the electrical connection (still plugged in). Post #9 of the link I gave earlier describes the symptoms of a failing N249, but if yours is not plumbed in then it can't influence boost (unless the pipework wasn't rerouted properly). I haven't noticed any mention of the diverter valve. They can fail and even a Forge DV can cause issues if it has worn seals, insufficient grease, or the wrong spring.
Failing all of this then I believe a Vagcom will read far more than a phone OBD, although I don't know how to use one even if I had one. Once you've exhausted the physical checks you might put out an appeal for Vagcom help on that section of this forum.
Hope you manage to sort it soon.

 

[JBRADY95]

Tried some different N75 valves over the weekend, tried pulling the actuator pipe off and running it too and tried different combinations etc.
With one of the N75 valves it boosted to 1.5 bar in 1st gear every time but after that it went flat again. The other one it boosted to 0.4 bar and that was it, it boosted on/off, sometimes and sometimes flat so definitely must be an electrical fault? Also been told throttle position sensor is another one to check?

 

[DorsetChap]

There's been a few suggestions on this thread but it's unclear whether you've had an opportunity to explore them further before trying to think of other issues that may be causing your boost symptoms. A Vagcom / VCDS scan should point you in the right direction (and is the best method of doing a Throttle Body Reset). Boost leak testing / smoke testing are best done under pressure because a split hose can act like a valve and open under pressure but seal in a vacuum (think of a diy brake bleeder made from a plugged split hose). The Diverter Valve can sometimes stick open or closed. Google "1.8t faulty DV symptoms" - again they can do what you're experiencing. Last but not least, an MBC will take out ECU control of the N75, although the ECU will close the throttle a bit (soft limp mode) if it detects overboost. When you've tried these suggestions along with any new observations as a consequence then, if it's still not resolved, hopefully others here will chip in with further suggestions. If you do find the issue please share it here for any others in the same boat.

 

[JBRADY95]

There's been a few suggestions on this thread but it's unclear whether you've had an opportunity to explore them further before trying to think of other issues that may be causing your boost symptoms. A Vagcom / VCDS scan should point you in the right direction (and is the best method of doing a Throttle Body Reset). Boost leak testing / smoke testing are best done under pressure because a split hose can act like a valve and open under pressure but seal in a vacuum (think of a diy brake bleeder made from a plugged split hose). The Diverter Valve can sometimes stick open or closed. Google "1.8t faulty DV symptoms" - again they can do what you're experiencing. Last but not least, an MBC will take out ECU control of the N75, although the ECU will close the throttle a bit (soft limp mode) if it detects overboost. When you've tried these suggestions along with any new observations as a consequence then, if it's still not resolved, hopefully others here will chip in with further suggestions. If you do find the issue please share it here for any others in the same boat.

Cheers dude. Ive tried various things that have been recommended but smoke/pressure test is quite hard for me to do and im not sure how to go about it.
Everytime i get researching one thing, i seem to uncover another possibility!

 

[Hedgehog Dodger]

Split breather pipes?

 

[JBRADY95]

Split breather pipes?

I have a catch can on? None of the pipes are charged/under pressure are they? One out the crankcase and one from the front of the engine at the bottom?

 

[JBRADY95]

Ok so...bought a new EGT sensor, intake temp sensor and a boost pipe which had a rip to the outside of it but i didnt think it went all the way through but replaced it anyway in case...aand still no change. No boost and wont go above 5500rpm.
First time i fired it up, boosted awesome in 1st gear and span up and took off, 2nd gear went flat again and that was it.
Is it possible for a clutch switch to cause issues?