Hi guys been a while since I've been active sorry, anyway a few months ago the car developed a misfire in cylinder 1&2, someone said try driving maf-less I did this and she drive perfect again, so I assumed maf at fault, I ordered a new one and decided I'll give her a service (filters and fluids) put the new maf on and again the misfires are back :@ same cylinders, when the car hits boost if feels like it holds back and bounces around (a rocking sort of feeling) and it the pumps out black smoke as trying to push through (think black smoke) and also sounds like a boost leak when at this point but I've checked for any oily residue from the "leak" any help or opinions are welcome

any engine codes??

 

could be a dodgy earth, coils breaking down - also just to rule it out, disconnect the maf again particularly if it is an aftermarket one??

I can't remember the codes as I've cleared them again but it said misfire cylinder 1 and then misfire cylinder 2, it's a genuine maf, I thought the original could have been beggared from excessive oiled performance panel filter so I've got a cosworth one for the new maf

What would be the easiest way to check if the coil packs are faulty? I'll be changing the plugs the weekend hopefully, I haven't had a proper look but are they awkward? It looks like I'll need to remove the airbox and possibly the battery and maybe the washer fluid bottle?

Simplist way is to put the coils from cal 1 and 2 on 3 and 4 and see if the problem occurs on 3 and 4

Fair enough, I know this is stupid but which cylinders are 1,2,3,4? Cheers hopefully all sorted soon

Black smoke would normally indicate unburnt fuel (no spark)

As you face the pulleys

1 closest left

2 closest right

3 furthest left (nearest the turbo)

4 furthest right .

Have you got separate coilpacks or a single one on the inlet manifold?

Seperate and cheers :)

No worries .

Check the coilpack connectors , breaks in the insulation and arc'ing marks on ends that connects to the spark plugs .

When removing the coilpacks wedge something between the coilpack body and the recess they sit in while you undo the 10mm bolt securing them in place .

This stops the coilpack twisting and stops you bending or splitting the insulation that fits over the spark plugs .

Also might be worth checking the inlet manifold earth , gapping the new plugs to 0.7 and taking care not to crack the porcelain when fitting the plugs .

I'm assuming there's plenty of space for a ratchet to fit? And thanks again I'll check the earth straps when changing the plugs and check for arcing marks and just general condition overall of the coil packs themselves

Not really it's quite tight

I use a short 3/8 converter attached (and gaffer taped) to the plug socket and a flexi rachet spanner as it's narrower than a rachet but a rachet will work with the right combo of little extensions

I've gaffer taped them together cos otherwise when you put the new plugs in you sometimes can't get the plug socket out without taking the plug back out [emoji6]

where you had the service, did they not pick up on the miss fire?

I serviced it myself as soon as I got a new maf, as I said without the maf connected it ran fine, boosted fine the only problem was eml with maf codes, I don't understand why it sounds like I have a boost leak with maf connected but no problems without, I assumed the black smoke would be over fueling due to dodgy maf but still doing it on the new maf

At idle I have about 18.6 vacuum, 5.7psi intake 0.3 fuel flow this is at 760rpm using torque pro

You would normally get a maf or map code come up if you've got a air leak , but not always and intake or vacuum leak might give a misfire symptom have you checked the y pipe under the tmic ?

Have you reset the codes ?

As somtimes the ecu can store a old code and still compensate for it even though you've replaced the part .

Will admit it Does seem a bit strange that your getting 2 cylinders missing all of a sudden

Codes have been reset, no maf codes, I'll take the intercooler off after it's cooled down abit to see if the y pipe looks bad, I'm finding it strange and frustrating, the amount of smoke and fuel I'm using is crazy yet when the maf was unplugged it got nearly double the miles and ran fine no smoke or missing

Ok so changed my spark plugs and moved my coil packs from 1&2 to 3&4 still have the misfire when boost comes in

P0301 & p0302 I don't know what else to check, lifted the tmic off checked all hoses and connections to make sure I'm not leaking boost

If the code is for a cylinder 1&2 misfire it does still sound like a electrical fault .

You've ilimatenated spark plugs and coilpacks so work your way back from the coilpacks .

Check the plugs are clean and without and breaks in the insulation between the coilpacks and engine loom .

Also check the pins are clean and insulation around the big grey engine loom plugs , one end is near airbox and the other end is near the battery/ windscreen washer bottle .

It might not show the symptoms when the maf is unplugged as the ecu might back the boost off a bit due to not receiving a signal from the maf .which would indicate a weak spark as higher boost might blow out a weak spark .

It could be a injector fault overfuelling and flooding the cylinders but I wouldn't expect 2 injectors on different heads to pack up at the same time .

Failing that you might have to bite the bullet and book it in for a rolling road dyno /fault find (about £50) at a reputable scooby friendly dyno/auto electrician

If you have coil packs are you sure there wasn't a very fine crack on the stem of it.I had the same problem I changed my leads and problem went

It won't be the actual packs as I've eliminated them, my misfires were cylinder 1&2 so changed the spark plugs and moved 1&2 coil packs with 3&4 cleared the codes went for another drive and still misfire 1&2, I've checked all the wires for any damage I can't see any signs of it, I might have to take it on a rr see if anything can be seen failing, get them to check the map of the car make sure there's nothing playing up in that area