Mis-Firing Cupra

[lee_woollett]

I've noticed over the past few days i've been getting some periods when driving when i put my foot down there is a little hesitation that i've not noticed before, i thought it could have been mis-firing. I looked under the bonnet today and noticed that both cool packs above the pistons furthest from the N249 (not sure of the numbering on the leon) were slightly raised (probably about half an inch or so). I've noticed this before but pushed them back onto the spark plugs and thought nothing of it. I then tried to drive my car half an hour later and it had a terrible misfire, almost as if one plug wasn't working at all, no power what so ever. When i looked under the bonnet again, the coil pack furthest from N249 had managed to raise itself by about 2 inches so that it was no longer in contact with the plug.

Has anyone else seen this or had this happen to them? Its one of those annoying little things that's going to drive me mad until i know whats causing it to happen.

 

[LEE69]

Are the spark plugs tight?

 

[lee_woollett]

I'll have to get my socket set out and see if i've got an extension bar long enough to reach down the head to the plug. What size are the plug's, i can't remember what size spark plug socket i have?

 

[james walker]

spark plug sockets are usually one size matey...

 

[lee_woollett]

I've always been led to believe that there are different size plug sockets.

Anyway, i found my socket and extension bar, when i put the socket on the plug, it was really loose and was about half way out (half undone) , just checked the next one to it but that one was tight. I've got to give it a good service in a couple of weeks so will check all plugs and whilst i'm at it, might do the N249 bypass as well, TB clean and TB reset at the same time.

Thanks for your help, will see how she drives tomorrow.

 

[james walker]

reset the ecu after youve done that little lot mate, maybe even clean the maf.
run sweet as a nut then.

 

[lee_woollett]

just put a new MAF on it about 3 weeks ago so shouldn't need to clean it. I was thinking of leaving the battery disconnected whilst doing it but then thought i'd use VAG COM to do it

 

[Damoegan]

iirc there are two sizes for spark plugs, 17mm & 19mm with 17mm being the most common.

 

[lee_woollett]

bloody hell on the way to work this morning the damn car started mis-firing again, stopped on the M1 between Jct 15 and Jct 14 to find that the coil pack on no1 piston had popped up again, even though i had tightened the spark plug up

As i was only a few miles from MK, i thought i'd drop into stealers (MK Seat) and get someone to look into it. They took all plugs out and re-tightened them and checked all coil packs. Took them about half an hour and they only charged me £12 + VAT. So far its not done it again...... maybe i didn't torque the plug up enough ???? anyway i'll have to keep an eye on it and see whether it happens again, maybe the coil pack is a bit knackered and isn;t gripping the plug tight enough.

They were so nice and gave the car a once over and found that i need a top up of oil, front brake pads are 80% worn and one exhaust bracket is broken..... total value£117 + VAT....... i think i'll be doing that work myself for a lot less