after 20 mins driving, TCS + EPC lights, car won't rev past 2k

[__B3NNY__]

Ok so the car seems like it has been broken forever! I`ve tried trying to find the fault myself via help from the forums but to no avail, so i bit the bullet as im desperate to sell and booked it in with SEAT only for them to give it the elbow because of the modifications carried out a local VAG garage also said the same.

This is briefly whats happening to the car along with the fault codes I'm getting.

Sometimes the car will run fine, the idle does flutter a little and the engine note does change but barley noticeable, i can drive it for approx 20minutes then it all starts to go wrong, most of the time it happens when slowing down or stopped i`ll get the TCS and EPC come on and the car will not rev past 2k rpm even with my foot flat to the floor and the revs are jumping about all over the place jumping between 800rpm and 1200k rpm. If i turn it off for 10minutes it will normally start fine but then it seems once warmed up again after a few hundred yards it all goes wrong again.

Ive found if i keep the revs below 2k rpm it seems to be OK.

I`ve replaced the temp sensor, also fitted and 2nd hand TB and re-adapted. Also tried a working ecu and TB from another members car.

Seat and local VAG garage didn't want to touch it as it had had "MAJOR" modifications carried out as Seat stated on there report, and advised me to see a performance garage.

My modifications are k03s with all the extras and revo stg2. I`ve done all the little bits N249bypass etc.. with all valves removed and replaced with resistors etc..

Gear box was replaced less than 500miles ago so im not sure if something could have been disturbed while the done this?

These are the faults Ive been getting,

Whats are your thoughts on the above?

Thanks David.

 

[m0rk]

what's the wiring like near the TB? damaged? kinked?

I wonder if it's got some increased resistance, and that's why it's throwing a wobbler?

 

[ian_cupra]

have you checked the accelerater pedal box?? could be something to do with that too, as the signal from there could be goosed, hence getting weird response from it? just another thought

 

[__B3NNY__]

Seems to be fine, ill have a double check later. I did notice that there is a big round bulk of wires incased in a round plastic case just under the TB this had plier marks on although it had been tamperd with.

 

[__B3NNY__]

Where would i find that ian? Had a look at the pedel before but couldt see any sensors etc..

 

[ian_cupra]

could be that, follow the wiring back from the TB and see if its that? could need a quick splice putting in, wiring could be crushed causing more resistance and hence giving you your problems

 

[ian_cupra]

Where would i find that ian? Had a look at the pedel before but couldt see any sensors etc..

yours in drive by wire aint it? lol

if you look at all the pedals, push the accelerator, you'll see all the mechanisum (sp) working, think it is next the the clutch, the way its set up

 

[__B3NNY__]

Yeh lol, i`ve seen that moving lol.. wouldnt that give its own error code tho?

Seems like quite a job to get to.

 

[ian_cupra]

not sure on the code, as it could be giving the wrong signal to the TB, so wont throw up a code for that, but TB could be picking up the problem, its only a thought mate, dont hold me to it

 

[revo carl]

have you done a throttle body alighnment?

 

[m0rk]

I think wiring failures report more as sensor faults - because they report back values that 'cannot' be right

 

[ian_cupra]

true mork, i'd be checking that wiring out, could just be dirt in the plug of the TB

 

[__B3NNY__]

Yup done a TBA, again a strange one as sometimes it will align fine clicks and get adpt ok in the box other times all i get is error and it wont align at all which also leads me to think tha its a dodgy wire somwhere.

When it first started going wrong after i replaced the TB i thought it may be a wiring issue, but im no mechanic let alone a auto sprakie so i wasnt sure really where to start apart from the wires coming from the TB itself.

Im guessing that the throttle actuator is the TB? but what is the throttle valve controller?

 

[DPJ]

I'd be looking for a wiring fault.....

 

[__B3NNY__]

I will do... cars at my brothers at the moment but im going to give it a whirl in a hour.

 

[Robbie C]

As above, I'd be suspecting wiring at this point

http://wiki.ross-tech.com/index.php/17953/P1545/005445
http://wiki.ross-tech.com/index.php/17579/P1171/004465

What's the angle sensor, is this the TPS?

Someone else with the same fault, but no cure listed -> http://www.passatworld.com/forums/archive/index.php/t-219733.html

Another loosely related issue that proved to be a wiring fault: http://www.passatworld.com/forums/archive/index.php/t-227645.html

 

[robreidmotors]

Have a look at the speed sensor, which is i believe known as G28 Speed Sensor. Reason I say this is a few people have had issues with it, which seem to be very similar to yours.

It runs ok until warmed up, then wont start, and after left for 20mins or 30mins starts again, only for same problem. Apparently the sensor is a magnet, and loses efficiency when warmed up, so a slight fault can cause stalling problems.

http://www.seatcupra.net/forums/showthread.php?t=201500&highlight=g28

Also the sensor may be fine but the wiring to it or connector dirty etc.

Think its located near the starter motor so could be prone to road dirt etc

 

[__B3NNY__]

Ill check that out also, ive been following that thread as symptoms are very simler.


Wouldnt the speed sensor bring up its own fault code if there was a problem there?

 

[robreidmotors]

I think usually they do. But I think I read one member who replaced it without a fault code and it solved it, im not completely sure though.

 

[ibizacupra]

g28 (crank sensor) usually throws a g28 code, and accounts for non starting typically. never seen one to throw up throttle body problems..

wiring or earthing somewhere would be my best bet to start.

you said g'box has been off at some point and pliar marks indicate someone had a go untwisting the plug (which is a complete arse to get off) so earth not on bell housing to battery or those wires to the t'body are damaged causing ecu to drop into safe mode.