Another missfire

[mac101]

i know there is loads of post on missfires but wanted to ask a few questions myself i have a 1995 R33 GTR standard set up (no mods) i have a slight missfire it happens from the moment i start the car up to the time i turn the car off it does not seem to affect performance(may be iam use to it ) but when you give it a bit you get some backfiring i have rulled out a air leak as i have the inlet manifold gaskets done and replaced all the vacume hoses what i want to ask where should i start looking
plugs
coil packs
AFM
O2 sensors
any advice on how to check the above apart from the plugs

and any items i have missed

thanks i advance

[mac101]

anyone please

[bhappy2cu]

The best and cheapest way is to borrow working parts that you have mentioned and see if it fixes the problem. Just a process of elimination.

Do you have any nice friends with gtrs??

I always have a spare set of everything that you have mentioned so when when the car isn't right I swap to see if it fixes the problem. In my case so far they were coil packs. The resistance test was within spec and no sign of any problems. However, swapping them for a good working set revealed otherwise. Maybe coz they are old.

Also, since your car is stock you can take it nissan and get them to check the car with the consult... but that will cost money.

Good luck.

[mac101]

Originally Posted by bhappy2cu

The best and cheapest way is to borrow working parts that you have mentioned and see if it fixes the problem. Just a process of elimination.

Do you have any nice friends with gtrs??

I always have a spare set of everything that you have mentioned so when when the car isn't right I swap to see if it fixes the problem. In my case so far they were coil packs. The resistance test was within spec and no sign of any problems. However, swapping them for a good working set revealed otherwise. Maybe coz they are old.

Also, since your car is stock you can take it nissan and get them to check the car with the consult... but that will cost money.

Good luck.

dont know anyone with a GTR seems a good idear to have a good spare of everything will have to look into that i have booked my car in with Middlehurst Nissan this comming week hopefully they will get to the bootom of the problem thanks for the advice

[GT-R Glenn]

Have you sprayed the AFM's with contact cleaner ?

[R33_GTS-t]

Does it stutter on full or part throttle?

[beaumackenzie]

sound like a spark plug to me or coil, which also could be related to the break down of the igniter pack.

sometimes it fires sometimes it wont, when it doesnt the fuel builds up in the cylinder and when the spark plug does fire it spits flames etc. not an unusual issue.

i have found a cheap alternative for replacing the igniter packs, it is from the nissan maxima or cefiro with the 2.5 or 3.0 litre v6, the earth is not in the same place on the maxima igniter pack however simply change the pins from 123456E to 123E456.

[mac101]

Originally Posted by GT-R Glenn

Have you sprayed the AFM's with contact cleaner ?

no have not touched them yet is there anyone type that people use

[mac101]

Originally Posted by R33_GTS-t

Does it stutter on full or part throttle?

no thats the thing it seems to drive ok no holding back on full or part throttle

[mac101]

Originally Posted by beaumackenzie

sound like a spark plug to me or coil, which also could be related to the break down of the igniter pack.

sometimes it fires sometimes it wont, when it doesnt the fuel builds up in the cylinder and when the spark plug does fire it spits flames etc. not an unusual issue.

i have found a cheap alternative for replacing the igniter packs, it is from the nissan maxima or cefiro with the 2.5 or 3.0 litre v6, the earth is not in the same place on the maxima igniter pack however simply change the pins from 123456E to 123E456.

a few people have pointed to plugs and coil packs dont want to start replacing eveything ££££ i would rather get the main dealer to have a look i know i will have to pay out main dealer money but it may be cheeper in the long run thanks for the advice

[matty32]

sounds like a coil or plug

either way you may as well change both

[UKPAISLEY]

Interesting, ! Prob not a coil , reason is the coil is effected in two ways, first it reacts to high temp and then performs badly, you dont describe this, as you have a problem from the start, and again the coils show spark problems under load or hard boost. I would go for the plugs, and go for NGK , you would also need to look at the temp range of the plugs as the higher ones have a littlle problem not running at high boost so are a bit lazy until the revs get up.

[mac101]

Originally Posted by UKPAISLEY

Interesting, ! Prob not a coil , reason is the coil is effected in two ways, first it reacts to high temp and then performs badly, you dont describe this, as you have a problem from the start, and again the coils show spark problems under load or hard boost. I would go for the plugs, and go for NGK , you would also need to look at the temp range of the plugs as the higher ones have a littlle problem not running at high boost so are a bit lazy until the revs get up.

thanks for your imput what range of plugs would you suggest

[frostmotorsport]

you should go for 7's or 8's at least. I run Iridium 6's in mine - had a misfire under boost a while back with the popping and belching out the tailpipe - I pulled the plugs and closed the gaps - as they were 1.1 - I closed them down to 0.8 which seems to have made a huge difference.

Also regarding the coils (at least on mine) the spring loaded bit that sits against the top of the plug develops a 'coating' on it, as if poor contact is causing sparking and they develop a sort of crust on the ends - so I cleaned this up with some fine sandpaper. Careful though, cos those bits can fall out when you remove the coil!!

Certainly, pulling the plugs will be worthwhile to see what state they're in. If the white insulator has brown marks coming up from the steel hex, they need replacing!

[kismetcapitan]

could be worn plug tips, which would give you a huge spark plug gap. Big gaps are no good on the Skyline - when you get on boost, they blow the spark out like a candle....in the wind