Seat Leon Cupra R 210 surging

[artfulsach]

Hi everyone, I have owned a Seal Leon Cupra R 210 Bhp 2003 plate since new.

Recently it has developed a problem where when accelerating hard, the car surges it's power, pulsating like it's give way and then comes back on and then gives way again. What is wrong with my car? It's completely stock and we'll maintained.

 

[mty12345]

2 things come to mind, either a faulty N75 valve (the valve that controls the amount of turbo boost) or maybe a weak fuel pump or bad fuel pressure regulator. Either way you should probably have a fault code stored, or if not then looking at live data on a scanner would be the best way to tell.

If you don't have access to VCDS or a high level scanner capable of live data, then you're best off taking the car to a VAG speciallist or some reputible diagnostic specialist. They should be able to find the problem 1st time, whereas a lot of standard garages will throw parts at it costing you a lot of money.

Some things you could do yourself is examine all the pipe work in the engine bay, particularly the PCV hoses and all vacuum lines, especially the hoses running to the N75

 

[artfulsach]

Thank you very much, the car is completely stock with no modifications, except a number of years the plastic recirculating valve was replaced with a metal one, a forge one I think still recirculating. Also the elephant trunk was also replaced with a samco version when the stock one failed. The boost lines have definitely never been replaced so I will looking into checking all of them. It also has the twin Intercoolers in the bumpers, could they have leaks cashing a problem or fractures from over the years.

 

[Alexis27]

I had a surging issue like you and a new N75 valve solved it

 

[mty12345]

Thank you very much, the car is completely stock with no modifications, except a number of years the plastic recirculating valve was replaced with a metal one, a forge one I think still recirculating. Also the elephant trunk was also replaced with a samco version when the stock one failed. The boost lines have definitely never been replaced so I will looking into checking all of them. It also has the twin Intercoolers in the bumpers, could they have leaks cashing a problem or fractures from over the years.

It's possible that you could have leak anywhere between the turbo and inlet manifold and definitely another thing worth checking. Not just leaks but poorly seated/popped off hoses as well, but much more likely that the problem lies in the thin vacuum hoses or the N75 valve itself. Some N75 info here in case it's helpful in checking it

Understanding the N75 Valve — 1.8T Tuning

18t-tuning.co.uk

The forge diverter valve is another thing to check, it could be that it can't hold boost and is leaking.

They are pretty complicated engines so without live data it's hard to tell, but all the above are certainly things you could check yourself without it.

 

[artfulsach]

Really appreciate all the advise, I have scanned it using a Delphi scanner and there are no fault codes, over the years I have replaced coil packs as they fail, so I don't think it's that as it quickly turns into that Subaru kinda sound. I will follow your advise, do you think for cost wise, I should also revert back to the standard factory Bosch recirculation valve also?? Apart from the elephant trunk which has been upgraded to a samco one, all the other boost hoses have never been changed, do you think I should replace them all?

 

[artfulsach]

I think I want to return back to the stock recirculating valve, it's stock 210bhp and it's going to stay that way also. I have heard that they have been revised and are much stronger and don't need servicing every year or split, my question is should I buy this from main stealer SEAT others mentioned it might be better to buy from VW or Audi as they might be better??

 

[artfulsach]

Again with the N75 should I also buy this from main stealer too, as there are ones available online?

 

[Alexis27]

Try https://seatdirectparts.co.uk/

 

[artfulsach]

Thanks again everyone for all the input

 

[artfulsach]

Good morning everyone, so I have an update I managed to get the latest part number version of the N75 and also the latest version of the stock recirculating valve have changed both and cured the pulsating issue. I also at the same time checked over all the hoses.

My new question is, at the same time I fitted a boost gauge in PSI now in all my jap cars previously I also T into the top of the valve which I have done on this my LCR 210 MK1. I am only getting 10psi. Is this correct? I did see another guide after saying your suppose to T into the fuel pressure regulator....

Many thanks for any help.

 

[mty12345]

Glad to hear that you got the surging sorted.

DV vs FPR has been an ongoing debate over the years, but bill from badger5 (probably the best 1.8t tuner in the country) said that the DV line is the best place to take it from. Sounds like maybe you have a leak in either your install or the pipework between the manifold and the DV. It goes though an N249 valve on it's way to the DV, so possible that it's leaking around there. It may not be big enough to cause a boost leak that the ECU can notice, but may be enough to affect your boost gauge by a few psi.
If you can't find a leak then you should probably log boost data from the MAP sensor vs your gauge.

 

[artfulsach]

Glad to hear that you got the surging sorted.

DV vs FPR has been an ongoing debate over the years, but bill from badger5 (probably the best 1.8t tuner in the country) said that the DV line is the best place to take it from. Sounds like maybe you have a leak in either your install or the pipework between the manifold and the DV. It goes though an N249 valve on it's way to the DV, so possible that it's leaking around there. It may not be big enough to cause a boost leak that the ECU can notice, but may be enough to affect your boost gauge by a few psi.
If you can't find a leak then you should probably log boost data from the MAP sensor vs your gauge.

Thanks for the response, I will most likely replace most the hoses went I get back on it, I am also going to use torque app to see what the ECU sees as the boost pressure. Can you tell me on a MK1 stock LCR 210 bhp what the psi should be??

Best regards Sach

 

[mty12345]

Thanks for the response, I will most likely replace most the hoses went I get back on it, I am also going to use torque app to see what the ECU sees as the boost pressure. Can you tell me on a MK1 stock LCR 210 bhp what the psi should be??

Best regards Sach

99% sure it was 12psi on the 210bhp model

 

[artfulsach]

Thanks for the reply I could have a slightly inaccurate gauge as it was fairly cheap, but I am not too far off, I think once I plug in my odb2 reader and get live data off the ECU and then change the hoses over hopefully it's all good. I got worried as when I googled it a lot of people were saying 22 to 28 psi

 

[artfulsach]

Also would anyone recommend plug and play tuning boxes off eBay for example for a stage 1 tune to give that extra ,30-40 bhp

 

[Alexis27]

Might not do anything, but try resetting the throttle calibration by turning the ignition on, engine off, and waiting for 3 full minutes.

Definitely worked on my old LC for fixing a low boost issue.

 

[Alexis27]

Also would anyone recommend plug and play tuning boxes off eBay for example for a stage 1 tune to give that extra ,30-40 bhp

A replacement ECU with stage 1? Complete gamble, but I'd be interested to hear if they caused any problems.

Audi TT 1.8t 225 MK1 BAM ECU 8N0906018CB *Stage 1* *Immo Off* | eBay

BAM 8N0906018CB. Audi TT 1.8t 225 MK1 ECU. 225 increase to 250-260bhp.

www.ebay.co.uk

You can just stick a BAM ecu into an AMK.

 

[artfulsach]

Might not do anything, but try resetting the throttle calibration by turning the ignition on, engine off, and waiting for 3 full minutes.

Definitely worked on my old LC for fixing a low boost issue.

That's a good shout, so ignition on two clicks, the one just before engine on, and then off and leave for 3 mins kool

 

[Alexis27]

That's a good shout, so ignition on two clicks, the one just before engine on, and then off and leave for 3 mins kool

Yep. Apparently it can get stuck at less than 100% throttle travel