Mis-firing

[rb180]

I did a search and i didnt find what i was after so here is my problem.

I was driving home the other night and all of a sudden my r32 gtr had a mis fire. Its over the whole rev range and sounded like it was running on 5 cylinders. So i took it to my mechanic and we narrowed it down to the first cylinder(the one furtherest to the front of the car) by pulling each coil pack plug and listening to see which one didnt change the exhaust note. The funny thing is that every now n then its fine and doesnt miss but majority of the time it does have the problem.

What could be the problem ?

Stuffed coil pack?

Coil pack Plug wires loose? (we did wiggle the wires while the the plug was connected and engine running it didnt change anything, the miss was still there)

Also i just replaced the spark plugs with bkr7e's about 1000kms ago and its been running really good with them up until this happened.

We also tested another spark plug in the 1st cylinder and the miss was still there and pulling the coil pack plug on and off made no difference. The miss was still there with and without the 1st coil pack connected.

The ignitor plug, bolts and earth cable at the back of the coil pack cover are all connected also.

My guess is its the coil pack fkd, but im no mechanic so i wanted to get some opinions on here first.

Any help would be great. thanks

[hecticrb25]

Is there fuel getting into that cylinder?

[rb180]

Is there fuel getting into that cylinder?

Not sure. Do you think it could be the injector fkd or clogged and not putting the right amount of fuel in ?

How would i check that ? or maybe ill just get my mechanic to do it. Im sure he would know what to do.

Thanks tho ill put it on the list of things to check when i take it to the mechanic again.

Ive got a set of 'split fire coil packs' coming so ill put them in when they arrive in a few days and see if the problem persists. If it does then ill look at what you suggested. Thanks

[700HP-GTR33]

You bought a pfc?

Who tuned it?

It seems like timing issues.

Drop the timing down 2...ie -2 and see if that changes anything.

The timing will go back to normal after you stop the motor.

Also it could be a faulty afm.....give it a tap and see if this fixes it.

If so..get it open..clean and re-solder.

[Slim Mat]

It would also be a good idea to check for injector pulse on that cylinder. Pull the plug off the injector and use a test light across the terminals, it should blink.

Fuel pressure is most likely fine, since the engine is still running.

Listen to hear if the that injector is clicking when opening, if it is, it is a good bet that fuel is getting in the cylinder.

You are probably on the right track with the coil pack.

[hecticrb25]

Misfiring is pretty easy to determine if you havent done anything major, check spark, check fuel and all the delivery systems for both.

It sounds like it would be your coil pack but no harm in checkin to make sure its gettin some juice and that the injector is actually working, you should be able to put a test light onto the injector connection to make sure its getting a signal to fire (while its running of course). If it is take your spark plug out and see if its covered in fuel (should be if all your missing is spark).

If all of that is covered its gotta be your coil pack (unless the wiring to the coil pack is screwed or the ECU isnt firing that cylinder).

Edited July 31, 2007 by hecticrb25

[rb180]

You bought a pfc?

Who tuned it?

It seems like timing issues.

Drop the timing down 2...ie -2 and see if that changes anything.

The timing will go back to normal after you stop the motor.

Also it could be a faulty afm.....give it a tap and see if this fixes it.

If so..get it open..clean and re-solder.

Yes i have bought a power fc but haven't got it installed yet. I also have a new water pump, cam gears, timing belt and those seals coming along with the coil packs. Maybe i should just get it all done at once.

But thanks for the other info guys. I will get my mechanic to check the injectors are actually pulsing and if they are then maybe the injector is clogged. I've got a good idea of what to check now tho. Thanks fellas

On another note who else in Melbourne (pref around the city area or not ages away) knows GTR's like the back of their hand besides racepace?(they are abit far for me) I need the power fc + boost controller installed and tuned, water pump, cam gears, timing belt, seals and split fires all installed.

thanks

[Haysey]

kinda sounds like the problem i was having when one of my injectors stuffed up....

tested everything even compression, sparks etc...

eventually i took the 2 bolts off the fuel rail, moved the rail back... took the injector out, put it in another cyl and then that cyl was missing.. i tested the injector with a multimeter and it had no current flow through it either...

was damn annoying, had a slight miss here and there, then a consistant miss, then just started the car and it sounded like a rexxy haahah

[sky_2.0T]

Yes i have bought a power fc but haven't got it installed yet. I also have a new water pump, cam gears, timing belt and those seals coming along with the coil packs. Maybe i should just get it all done at once.

But thanks for the other info guys. I will get my mechanic to check the injectors are actually pulsing and if they are then maybe the injector is clogged. I've got a good idea of what to check now tho. Thanks fellas

On another note who else in Melbourne (pref around the city area or not ages away) knows GTR's like the back of their hand besides racepace?(they are abit far for me) I need the power fc + boost controller installed and tuned, water pump, cam gears, timing belt, seals and split fires all installed.

thanks

borrow some coil packs, see if that works. Do one thing at a time, perhaps afm too. Mine was missfiring and running like crap, and it turned out to be the ecu. sounds like it could be a pack too. but theres several possibilities with these older cars, things get tired!

[rb180]

was damn annoying, had a slight miss here and there, then a consistant miss, then just started the car and it sounded like a rexxy haahah

That sounds alot like what happened to me but it skipped the constant miss part lol it just had a slight miss here and there but ran well after i did the service with the new plugs. Then all of a sudden its like sumone flicked a switch and that first cylinder turned off.

i would borrow some coils but i dont know anyone else with the same car.

My plan of attack is

Wait for coils packs to arrive. Install them and see if its still there.

Then check injector pulse and injectors. Then if its still there ill move to

AFM then

ECU.

Hopefully its just the coils or something easy lol

But yeh which other workshop in melb knows their gtr's well besides racepace?

[700HP-GTR33]

That sounds alot like what happened to me but it skipped the constant miss part lol it just had a slight miss here and there but ran well after i did the service with the new plugs. Then all of a sudden its like sumone flicked a switch and that first cylinder turned off.

i would borrow some coils but i dont know anyone else with the same car.

My plan of attack is

Wait for coils packs to arrive. Install them and see if its still there.

Then check injector pulse and injectors. Then if its still there ill move to

AFM then

ECU.

Hopefully its just the coils or something easy lol

But yeh which other workshop in melb knows their gtr's well besides racepace?

I have a set all in good order.

Have new splitfire ones installed.

You are welcome to come put them on and see if it fixes it.

Can you drive the car?

Edited:Also have an injector if this does not fix your problem.

[rb180]

I have a set all in good order.

Have new splitfire ones installed.

You are welcome to come put them on and see if it fixes it.

Can you drive the car?

Edited:Also have an injector if this does not fix your problem.

Thanks for the offer bud. Ive already got the coil packs coming so ill prob just wait for them, install them and see how i go from there. Atleast i can rule out them as the cause if the problem is still there.

I can drive the car if i have to but id rather not for now till i get the coils done atleast.

I may need to borrow or buy that injector off you though if the coils arent the problem. So ill let you know champ.

I really appreciate the offer tho. Thanks!

[Ryan1200]

Why not put no1 coil pack in another cylinder and see if the problem moves. If it doesnt help then try doing the same with spark plug. And again if this hasnt moved your missing issue onto another cylinder then look at you injector/wiring.

[hazerb30]

Yeh thats what i thought as well ryan. Im going through some missfiring problems on my gtr at the moment as well. This is under the assumption that the coil pack from cylinder 3 would actually fit in cylinder 1. I cant see why it wouldnt

[TTT]

yes they are interchangable.

swap and see if the miss goes to the next cylinder with it.

[rb180]

I'll try interchange the coil packs aswell thanks!

If the miss follows where the coil pack is put then i can safely say the coil pack is rooted right ?

My split fires should be here soon so ill just chuck them in and see from there if i dont get a change to swap the coil packs around.

[arep3]

My GTR is missing at times as well. but yea not constant. another option you could look at is earthing. old car, small earthing wire. i haven't re-earthed my ignitor and coils yet. too lazy. i will get around to doing it soon enough though. tomorrow is wash and polish day but! good luck. i hope the splitfires fix it for ya

[heller44]

Have you tried removing the coil cover and watching at idle in the dark?

I saw blue arcing around the base of a couple of coils.. before I re-varnished them..

The contact in the base of the coil.. where it touches the head of the spark plug.. make sure that is a good clean contact..

And definately with ^ about the earthing.. a bad place is the earthing to the ignitor pack as well.

james.

[rb180]

ok so my split fire's came today and i installed them.

Took the car for a squirt around the block and all is fixed. Seems that the first coil pack was the problem.

The car revs alot smoother and doesnt really have any sort of tiny miss anymore.

Im very happy with the result and the split fire's are good good value!