Annoying problem

Jan 15, 2021
8
1
Hi i have a 53 leon cupra 1.8 auq. Ive had it for about 18 months and its always had a problem where at about 1700-1800rpm it hesitates or holds back for a split second. If i dissconect the maf sensor the problem stops, which says to me that the maf sensor is the problem. But today i have fitted a brand new maf sensor to it and its doing it again. Its really annoying me now so im hoping someone on here might be able to help me. Thanks in advance
 
Jan 15, 2021
8
1
Do you have any error codes? Checked for boost leaks? clean your MAP and IAT, throttle body ?

any mods?
Thanks for reply
No error codes. And i dont think there is any boost leaks but it does not do it every time. Surely if it was a boost leak it would do it everytime i pull away or accelerate, correct me if im wrong?
And no i haven’t cleaned anything yet.
It has a k&n induction kit, is decatted and has a dump valve. The dumpvalve was already fitted when i got the car so im now wondering if thats whats causing the problem due to being the wrong one maybe. But i dont know as im not very clued up on these engines, its the first one ive owned.
 

Connor H

Active Member
Dec 19, 2019
890
444
Essex
Thanks for reply
No error codes. And i dont think there is any boost leaks but it does not do it every time. Surely if it was a boost leak it would do it everytime i pull away or accelerate, correct me if im wrong?
And no i haven’t cleaned anything yet.
It has a k&n induction kit, is decatted and has a dump valve. The dumpvalve was already fitted when i got the car so im now wondering if thats whats causing the problem due to being the wrong one maybe. But i dont know as im not very clued up on these engines, its the first one ive owned.
is it atmospheric or recirculating dump valve? These engines dont play nice with blow-off style DV's.

Theres lots of info and similar symptoms on these engines out there, but it seems to be a needle in a haystack type thing. It might even be your N75, but its hard to say and not a good idea to just throw money at it.
 

Connor H

Active Member
Dec 19, 2019
890
444
Essex
Thanks for reply
No error codes. And i dont think there is any boost leaks but it does not do it every time. Surely if it was a boost leak it would do it everytime i pull away or accelerate, correct me if im wrong?
And no i haven’t cleaned anything yet.
It has a k&n induction kit, is decatted and has a dump valve. The dumpvalve was already fitted when i got the car so im now wondering if thats whats causing the problem due to being the wrong one maybe. But i dont know as im not very clued up on these engines, its the first one ive owned.


Also it being decatted without a remap will probably effect it in such a way
 
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Jan 15, 2021
8
1
is it atmospheric or recirculating dump valve? These engines dont play nice with blow-off style DV's.

Theres lots of info and similar symptoms on these engines out there, but it seems to be a needle in a haystack type thing. It might even be your N75, but its hard to say and not a good idea to just throw money at it.
I wouldn’t know what type it is and i cant see any writing on it. Yes i have searched loads online and seen afew people with the same problems but they never seem to say what the problem was in the end. Or they never got to the bottom of it!
 

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Jan 15, 2021
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Also it being decatted without a remap will probably effect it in such a way
It was like it before i fited the decat. Just spotted its wet around one of the injectors, could that be the problem?
 

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Connor H

Active Member
Dec 19, 2019
890
444
Essex
Hi mate yeah that’s a blow off style valve, might be the combo type but I’d change it for a standard or forge recirculating one. Start with that for sure. Check out some threads on having blow off style valves on these engines, see what the conclusion on them is.

That injector does look dirty, I’d give it a good clean and monitor it. It could be an injector cup is leaking, or maybe the injector seals themselves. Both fairly easy jobs.


Sent from my iPhone using Tapatalk
 
Jan 15, 2021
8
1
Hi mate yeah that’s a blow off style valve, might be the combo type but I’d change it for a standard or forge recirculating one. Start with that for sure. Check out some threads on having blow off style valves on these engines, see what the conclusion on them is.

That injector does look dirty, I’d give it a good clean and monitor it. It could be an injector cup is leaking, or maybe the injector seals themselves. Both fairly easy jobs.


Sent from my iPhone using Tapatalk
Okay mate il sort them things first and see what happens. Thanks for your help
 

300bhpdaily

Active Member
May 26, 2020
556
239
I think I’ve got a spare Bosch diverter I took off when I fitted the forge one. How far are you from Basingstoke?
 

Sl1ced

Active Member
Oct 10, 2020
722
351
Mate I have an AUQ and speaking to others, I have experienced the same since buying it and so have others. It don’t happen all the time but literally feels like the boost is dumped for half a second. I’ve changed loads and others have too, it still happens


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Jan 15, 2021
8
1
Mate I have an AUQ and speaking to others, I have experienced the same since buying it and so have others. It don’t happen all the time but literally feels like the boost is dumped for half a second. I’ve changed loads and others have too, it still happens


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What parts have you changed so far mate? Also have you done any of the deletes on yours? Im thinking about doing them if i cant sort it as that might rule out afew possible things. I really want sort it.
 

Sl1ced

Active Member
Oct 10, 2020
722
351
What parts have you changed so far mate? Also have you done any of the deletes on yours? Im thinking about doing them if i cant sort it as that might rule out afew possible things. I really want sort it.

I’ve done all the deletes, n249 112 and sai. New vac lines everywhere, new TIP, new DV pipes and deleted the pcv system as well as a good service.


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Jan 15, 2021
8
1
I’ve done all the deletes, n249 112 and sai. New vac lines everywhere, new TIP, new DV pipes and deleted the pcv system as well as a good service.


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Okay mate thanks for the info. Im starting to loose hope! So have you given up trying to sort it now?
I been wondering if a remap would cure it but i also think its probably abit silly to remap a car thats got a fault.
 

Connor H

Active Member
Dec 19, 2019
890
444
Essex
Okay mate thanks for the info. Im starting to loose hope! So have you given up trying to sort it now?
I been wondering if a remap would cure it but i also think its probably abit silly to remap a car thats got a fault.

If its not throwing any codes is likely the ECU adjusting the values it see's different because of the mods.

Mine sort was on/off/on/off at partial throttle, i could see the boost gauge dip even tho my foot hasnt moved. I personally reinstalled my n249 and it seemed to help it, but ive also got a new n75 and a remap which has completely ironed out any lumps.
 

Sl1ced

Active Member
Oct 10, 2020
722
351
If its not throwing any codes is likely the ECU adjusting the values it see's different because of the mods.

Mine sort was on/off/on/off at partial throttle, i could see the boost gauge dip even tho my foot hasnt moved. I personally reinstalled my n249 and it seemed to help it, but ive also got a new n75 and a remap which has completely ironed out any lumps.

See I tested it with and without the mods and it didn’t seem to make a difference either on mine it’s interesting to see could potentially be n75 because that’s all I haven’t changed


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Connor H

Active Member
Dec 19, 2019
890
444
Essex
See I tested it with and without the mods and it didn’t seem to make a difference either on mine it’s interesting to see could potentially be n75 because that’s all I haven’t changed


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if you do get a new N75 just dont skimp on anything but OEM
 
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