Sometines a missfire and idling a bit up and down ?

[Dan20v]

Basically whats in title . Last few days im down on power and its a bit julty on pull off and speeding up . I started it up just now and pulled off and it wanted to cut out and lost power but i turned it off and back on smelt alot of unburt petrol but thats it . Coil packs ? Plugs ? This is the first petrol turbo i have had ow and its a cupra 1.8t 20v
Thanks dan

 

[davezx]

Seems almost evrry cupra is having these same problems.
Wish i could be of some help but am in boat as you are too and been changing parts and checking bits for the last month.
Hope you can get it sorted soon.

Sent from my XT615 using Tapatalk 2

 

[t0m]

Could be spark plugs, coil pack starting to go, faulty N75 valve along those lines if it's pretty noticeable.

 

[Mk1 banana]

Check plugs
Coil packs are notoriously common
My number 3 coil pack gave up on the remap, so I have 3 good and 1 half decent (pattern) coils
Oem were only £20 ish+vat each

To pin point the miss, you could unplug them one at a time, if it makes no difference, you found it (probably make a little difference any way, as they run wasted sparks)


Made in Spain, made better in England 223.3hp 263.8lbft

 

[Dan20v]

Check plugs
Coil packs are notoriously common
My number 3 coil pack gave up on the remap, so I have 3 good and 1 half decent (pattern) coils
Oem were only £20 ish+vat each

To pin point the miss, you could unplug them one at a time, if it makes no difference, you found it (probably make a little difference any way, as they run wasted sparks)


Made in Spain, made better in England 223.3hp 263.8lbft

Do I do this with the car not running one buy one ?

 

[Dan20v]

Cheers peeps I gonna get some today worth having spares so I find the dodgy ones and keep some in boot and I get plugs as well

 

[Mk1 banana]

Car running,
Just unplug one at a time, if it stalls/ tries to cut out, plug it back in and try next one.

If you un plug number one (closest to crank pulley) and it runs only slightly worse or no different then it's where the problem is... If it near on cuts out, plug in and do numbers 2,3,4 same way...

When I said wasted spark before, it means coils one and four are linked as are 2 and 3, so they will affect eachother when unplugged, but not as bad as unplugging both coils together,
Good luck mate


Made in Spain, made better in England 223.3hp 263.8lbft

 

[Dan20v]

All done

 

[davezx]

What was the problem in the end?

Sent from my XT615 using Tapatalk 2

 

[Dan20v]

Well just bought new plugs and coil packs and much better but not 100% .was funning 17 psi now running 12-14 ??

 

[Mk1 banana]

Boost is load/ temperature dependant, it will vary, but if that's it- I couldn't say. :s
Maybe coincidence?
Did you disturb anything else while doing the coils and plugs (somehow?)?


Made in Spain, made better in England 223.3hp 263.8lbft

 

[leoncupra2012]

Coolant temperature sensor?

Mines doing similar, dodgy idling, popping and banging when cold, smelling of unburnt fuel, and if i turn it off and start it back up it idles high because the sensors knackered and the car cant tell the ECU the coolant is already hot so it runs in warm up mode constantly, over fuelling etc

 

[Dan20v]

I done all temp sensors and thermostat .I think I did not disturb anything . Still getting a bit of funny idle got told could be n75 valve ? Or a silly cheap cone air filter someone put on it ? Sorry guys I going way off track

 

[Mk1 banana]

N75 can cause boost to be erratic... I suppose if it tries to boost at idle, it can upset the mixture aswell.


Made in Spain, made better in England 223.3hp 263.8lbft

 

[Mk1 banana]

Ect sensor is also possible, as you say...


Made in Spain, made better in England 223.3hp 263.8lbft

 

[t0m]

Check N75 connection. Mine came loose once after some work had been done at a garage and it was only making half boost!

 

[Dan20v]

Can i ask were the n75 valves are on the 1.8t and whats the ect sensor ?

 

[Mk1 banana]

N75- between the air filter and turbo, on the turbo inlet hose, just after the air filter, it's a three way connection, that has an 8mm hose that goes down the back of the engine to the waste gate (on turbo) and the other hose goes to the metal turbo pipe

Engine Coolant Temperature sensor


Made in Spain, made better in England 223.3hp 263.8lbft

 

[Mk1 banana]

Not the clearest, but you'll see a thin (4mm) yellow vacuum line and a slightly bigger one behind it, the 8mm one behind it (dirty one) goes between waste gate and n75


Made in Spain, made better in England 223.3hp 263.8lbft

 

[Dan20v]

Would this cause my car to idle funny ? As well i got a boost gadge as well it dont move much on idle think its just a vibration . And thos morning i started my cat up went to pull away and it nearly died and the revs were up and down for about 8 seconds fort it was going to cut out but it sorted its self out ? Just had new colent sensor . Thermostat coil pack and plugs