I was away with the family for a few days, before we went i decided to change spark plugs. tightened them down as per instructions (half turn from seated) but then undid them as was worried i'd done them too tight so i nipped them all up snug, and then drove car, all felt fine. Did 180 miles, all good. 

Coming home yesterday, sat in traffic, suddenly misfiring with a flashing engine light (yellow engine symbol) and strong smell of fuel. turned off car, and checked tightness briefly of plugs (happened to take a few spanners in back of car). Cylinder 2 was able to get a slight turn on the plug with a  small wrench. re-started the car and felt fine.

 

Decided to buy a replacement coil pack on route home from eurocarparts, and carried on driving. About 15 mins later, same thing again, bad misfire, flashing engine light, and this time the engine light stayed on once finished flashing. I Pulled over as soon as this started happening and started swapping the coil packs one at a time to isolate the problem. Started with coil 2 first (when i took plug 2 out i thought it was ever so slightly blacker than the others), started car after each swap of the coil packs and each time was still misfiring and i had to give it some throttle on one of two occasions to get it started, this is when the smoke from exhaust appeared.

 

Finally after putting coil from cylinder 4 in number 1, and with the new coil in cylinder 2, the car seemed to run a bit better but took a while to start and fully smooth out as i drove off. During this trial and error process i had a fair bit of smoke out the exhaust  and a burning smell. Came home, 90 miles, car drove fine, no issues. 

 

Today i checked all plugs again, all look fine although number 2 was a little wet around the seated crush washer and inside the edge of the spark plug hole. I have a basic ODB scanner so plugged it in and got misfire cylinder 2 code. Have been out in the car and done 30 miles or so today, no issues. Given it a good thrashing through all gears.

 

Could this have been the coil or my lack of torque on the plug, or was this potentially a stuck injector? 

 

thanks in advance

Edited 2 September, 20178 yr by kton200281

Just an update, been out in car and same thing - this time flashing engine light followed by EPC light and steady misfire. Booked in to a specialist to sort this week, will post the result. Smelt of fuel and burning so i think is stuck open injector but will see.

I had exactly the same symptoms with mine earlier this year and that turned out to be an injector stuck open. Injector replaced and all good since

Fault was indeed fuel injector for anyone who has this issue in future and performs a search

What was the approx cost to replace the injector?

 

On spark plug torque, I've always managed to tighten without issue by using the plug mfr instructions based on turns. I haven't got the NGK packaging in front of me but it was something like nipping up to gasket and then another 3/4 turn (follow spark plug packaging). 

 

What is important to note, once the plug has been installed, removed and then re-installed, the number of turns changes, from memory on NGK to 1/12 of a turn (but refer to mfr spec). This  is because the crush washer will already be compressed. 

 

You shouldn't use lubricants on thread either, especially if using a torque wrench as that messes things up Edit: (the specified torque that is). 

Edited 5 September, 20178 yr by TheClient

Glad you got it sorted. Sounded too similar to what I experienced with mine not to be the same thing. 

Spark plug you are correct on NGK packaging states 1/2 to 3/4 turn on initial installation, to crush the crush washer. If removed and re-installed, then its 1/12 turn, so basically not much just tighten it down by hand then 1/12 / snug. 

Cost to replace injector, £368. £158 for the injector inc vat, and £210 for the labour. 3.5 hours. 

 

57 minutes ago, Pods said:

Glad you got it sorted. Sounded too similar to what I experienced with mine not to be the same thing. 

Thanks for your advice