jayjaycupra1.8t

Active Member
Aug 30, 2013
93
0
Hi everyone

I have this problem with my car while driving....the epc light comes on and the car wont drive. When this happens the car sounds like its misfiring badly and shakes all over the place. If I press the accelerator it sounds like it tries to rev but wont go anywhere above 2500 at most...its completely undrivable.l...as if something is holding it back.

this is intermittent and can happen at speed on the motorway....or when taking off from a standstill....or slowing for a red light then pushing the accelerator. I cannot replicate it...it seems to do it when it wants to.

all I have to do is turn the ignition off and on again and everyhing is fixed.....car drives perfect. I can flick the ignition off and on at speed when it happens and all is normal again

Anyone have any ideas as to what is causing this????

I have searched and searched but I havent found anyone who has had this problem.

I have reset the throttle body with vagcom. No faults codes.

I have had the car 7 months now and it started doing it about two months after I got it

Engine mods - front mount intercooler, remapped by Jabbasport, jetex cone filter, sai and n249 and pvc deleted, forge tip, silicone hoses (halfway through replacing the lot), lpg system

and yes it was doing this before the lpg system was installed.

Any help would be greatly appreciated.
 
I'm sure the EPC is something more to do with the throttle cable (I've seen it in my user manual bear with me and I'll have a look but it's more to do with the throttle cable not being read properly hence it'll misfire etc

Quick google search found this so it won't be engine related so much it's more to do with dodgy connection somewhere?

http://www.seatcupra.net/forums/showthread.php?t=151271

Have a scan in the electrical side of things more than the engine itself as I'm guessing the engine will pull like a train still as it stands but if it's not getting the correct signal through that's what'll be causing your issues not the engine itself

A really weird one which the search shows but tap your brakes and check all lights work, If not it's apparently a common thing on the brake light switch which is at fault somehow :/
 
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Cheers lads!!!

I knkw the light has something to do with the drive by wire.....however all of my searches that I have done come up with either people not being abke to use the throttle at all when starting.....or having the light on constantly.

mine is different....seems to do it whenever it wants.

vagcom shows no faults whatsoever......csr drives absolutely perfect and pulls as it should.

its just this happens every now and then and as I said flicking the ignition off and on and its sorted.

anu ideas what sensors I shoukd look to change???

Is feels as if the car is doing this to protect itself....its like when I give it a load of throttle it kills itself. But it only does it when it wants to
 
As I posted in the earlier link it maybe something to do with the brake switch so perhaps take a glance at that although I can't see why it would be related if it's only intermittent?

Have you tried scanning the internal electrics?
 
Brake lights are fine....when this has happened in the past I have checked them....read that aswell somwhere.

im puzzled as to what it is????
 
Whole car scanned...I have vagcom.

No fault in any addresses.

well one fault relating to the sai delete but this was happening months before that
 
Apologies mate....when it does it the light stays on.....when I flick the ignition off and on then the light has gone and everythjng is back to normal.

I did once get the chance to scan with my torque app when it hppened....I left the car atls it was and plugged in it and came up with no codes. However I dont really trust the torque app. Vagcom is a bit hard to csrry around all the time waiting for this to happen so I will stick my odb scanner in the car and scan it with that if and when it happens again.
 
Does this happen at high constant speed? Say 80-90mph?

Had a random fault on my leon fr at speeds above 80mph causing my vss to drop off.

Cleaned all the engine bay earth points, earth strap and positive strap and everything is back to normal.
 
Whats the vss mate??

Doesnt happen at a contant speed....happens as and when it wants....motorway sppeds or normal speeds....its completely random
 
Vehicle speed sensor.

Whip the battery and tray out and check the earths as it's a water trap under there.
undo and check the connections they should be shiney clean not corroded

Might fix it as it's random but even if it doesn't you've not spent any money :)
 
qypujy8u.jpg


Make sure all the connections are sound to start



Sent from my iPhone using Tapatalk
 
You guys are great....thank you all for your help.

Adam - I have relocated my battery to the boot a month or so ago....all connections were fresh when I did this. Just had another look over them all and all fine.

Kent cupra - thats great I will have a look over the connection on the accelerator peddal. Information was very interesting.

Thinking over it one of the paragraohs states that the throttle body can move independently from the accelerator peddle.....so I am wondering if my throttle bady is the problem?? Maybe its sticking or the motors in it are knackered?? Vagcom shows no faults and I can see the butterfly moving smoothly when I took it off and had someone oush the accelerator.

Puzzled still....EPC system sounds like a complicated thing

whats your thoughts on my ecu being knackered?? Ive read this around in here and im dreading it :-(
 
Next step after checking connections would be to Clean the throttle butterfly and housing and then readapt it via vcds
 
Cheers mate.

alreading cleaned it whacked a new gssket on and adapted it with vagcom but no joy.

problem is its intermittent....would be alot easier if the problem was there all the time.
 
could your throttle pedal be faulty? Mine was, but I didn't get quite the same symptoms as you (no EPC light). The pedal didn't return all the way up by itself (resulting, for instance in random high idle values when the car is at a standstill). I found the car went into some kind of limp mode (didn't boost above 8psi) when I started the engine without holding the throttle pedal up. If I start the engine with the throttle pedal held up, it boosts as it should (circa 19psi). I replaced the throttle pedal and it solved the problem.

Not saying it's the same issue, but it might be worth checking.