Help! Rb25De Neo Misfiring (Intermittently?!)

[Pr0x1mity]

Hey guys,

So my cars been giving me a bit of trouble lately. It's been misfiring and chewing through LOTS of fuel.

Normally it goes like this:

Turn car on

Car either misfires straight away or runs fine for a few seconds followed by misfiring.

Misfire continues (NOW ON TWO CYLINDERS MIND YOU!) for a while, sometimes up to 45 mins or so.

After a bit of driving around with about 20kw of power at the wheels (all 4, it's a GT4) the misfire goes away. one goes away a lot faster than the other.

Driving fine now, normal power at the wheels and uses a lot less fuel

What could it be? I've had coil pack problems in the past. I replaced one followed by a whole lot of Yellow jackets (mind you i ended up frying 2 yellow jackets and having to buy replacements) but since putting the yellow jackets in it's not fixed the misfire.

Another idea is it could be the injectors? Faulty on the electrical side of the injectors that is.

I've got an OBD2 bluetooth scanner and consult cable converter but haven't been able to find software that would let me use it on my macbook (also have windows laptops available)

Occasionally I've had a slight smell of petrol as well. This is what led me to believe it could be to do with the injectors. Do the injectors die like the coils after a certain amount of km's? haha.

Help would be appreciated. I've had to live with this for 2 years but it's got a LOT worse. It was OK when it was once in a blue moon, but it's bad now. I've just been riding the bike and not taking the car.

My options are to try fix it my self (preferred)

or to try get more shifts in-between uni classes and try pay to get it fixed (would be tough)

EDIT: Also if any melbourne mechanics/handymen want to look at it for me in exchange for some services in IT (studied computer sys engineering and fixed computers before going back to get a science degree) i'd be more than happy to do a trade off to take a look and fix up a computer/laptop/mac in return

Edited February 23, 2013 by Pr0x1mity

[Pr0x1mity]

Morning edit: Just read ECU code. I believe it flashed 21 for me. So this means coils or spark plugs then?

[jessiek]

^^ spot on.

[Pr0x1mity]

Ahh well. Email is sent to get a return on these Yellow Jackets and I'll head down to autobahn and get some new plugs and gap them to 0.8. If that doesn't fix it... I'll be damned.

[Pr0x1mity]

AH okay. So now I have to swap out each coil individually to check which one is faulty.

Is there any other way of finding out what coil(s) are misfiring? Or is there a way to put it back together so that I have access to the coil trench?

[RB25DETC33]

Start the car dude with all coils in. If the car is missing while its idling simply unplug #1 coilpack if the engine gets worse then that coil pack IS firing. Plug it back in and move to the next one. Keep doing this until u unplug a coil pack which has no effect on the engine. This will be your faulty one.

[Pr0x1mity]

Is there a way of pulling it all apart and putting it back together with access to the coils?

Do I just pull the engine cover off and disassemble and take the coil cover off and then reassemble?

[RB25DETC33]

Is there a way of pulling it all apart and putting it back together with access to the coils?

Do I just pull the engine cover off and disassemble and take the coil cover off and then reassemble?

you have to remove the throttle body to be able to get access to the coil pack cover screws. just remove the induction hose as a complete unit with afm still attached. disconnect all the vac lines to free it. the simply remove throttle body indution pipe as one hole piece. You will need to remove the 4 or 6 hex bolts at the start of the plenum. Disconnect the vac lines and remove the part, make sure you know where all the vac lines come from, may be a good idea to take pictures before you pull it all apart.

[Pr0x1mity]

Hmmm ive pulled it apart before. It isn't too hard.

The part I dont understand is, once I pull it apart and gain access to the coils, what needs to be put back together for the car to run? Do I need to reattach the throttle body and vac lines?

Or can I pull it off and start the car for long enough to pull the coils one by one?

[RB25DETC33]

Pull it apart, then remove the black coil pack cover, refit everything. The car will then run and ull have access to the coil pack plugs. Although coils 3 4 5 will be a bit tedious to reach under the split pipe.