Still Misfiring. Not Plugs, Not Coil Packs, What else?

[WLD747]

After reading few more posts regarding this problem. Ive decided to turf out my $30 pod, possibily a oiled one and going back to the stock air box. Im certain that by going back to the stock air box our problem will disapear due to the air resude on the afm clogging our boost levels, maybe. Anyone given it a go please post results.

If not i need to take it to someone for a timing adjustment as ive heard advance it to 15+ and it should disappear.

otherwise coils packs next week, damn.

will post results.

cheers

ak

[AutoTrust]

Max GT its your computer (ECU) Auto skylines have a different and more conservative program and a link to the auto trans computer that will retard ignition timing sooner than a manual and perform a fuel cut sooner at higher boost levels. This has been a big problem for me for 12 months! Anyway I bit the bullet and tried a modified manual computer.... and YEAH BABY YEAH!! now i'm running 1 bar boost and have to be careful changing to second because there is no rev cut now so savage gear changes are all the go. Also if your going to try this, then make sure to get a dyno tune afterwards to be sure.

Strich9ine i don't know if this helps buddy but if your car is a manual and a series 2 and you want some split fire coil packs then drop J-SPEC a line. [email protected] They have a new set collecting dust in the office! it also wouldn't hurt to try a mates ECU. the ecu in mine caused all sorts of problems in the previous car and we tried every thing to no avail just to find that it was the ECU. Hope this helps guys. Have a nice day.

[DAMQIK GTS-T]

this site talks in detail of the problem and possible fixes

http://www.wave.co.nz/~hksnz/techfiles/pow...rlost25det.html

[WLD747]

well im not sure about that website above but im gona buy some injector cleaner whatever is expensive and see what happens maybe a clogged injector could be the cause but most likely its the coils.

does anyone know where the vvt thing is?

cheers

ak

[AutoTrust]

The VVT actuator is on the front of the cam cover. it is round and made of cast alloy.

[sky^rkt]

ive got a gts pillarless r31, runin the niccs rb20det and im havin the same prob! as son as i put the new 3 inche exhaust form turbo , i was get missfires at about 4-6 grand, very anoying at times! ill try cleaning injectors, getin a full tune up, and adjustment of the afm, hopefuly i fix the prob =/

[AutoTrust]

sky^rkt

Chances are that your ECU is responsible for the missfire, when you fitted the exhaust you removed a restriction from your engine allowing it to boost more, the factory ECU could be retarding your timing and or cutting your fuel, you may also find the problem to be more pronounced when the air is cold in the morning or at night. Are you still running stock boost?

[sky^rkt]

yeh boost is still stok as a rock, exhaust is my only mods, and when car is cold and i try hammer it, it wont missfire

[AutoTrust]

Well, after your tune you'll have more of an idea of what it isn't. these things are usually not fixed easily, the more information you can give about the conditions when the missfire happens the better. Also, nissans run different parameters when the engine is cold, this is to protect the engine. you should avoid caning until the temp gauge reaches normal operating temperature. I found i had less missfiring problems when the engine was cold but when the engine warmed up and the air was cold outside misfiring was more pronounced. Good luck

[Mase]

A friend had a similar problem with his 25 similar to yours skyrkt, he changed his exhaust again and it sorted itself out. No idea why.

[sky^rkt]

yeh, i was told just to try it when it was cold to see if it wuld happen and it didnt, i always let the car warm up to opertating temp, probably in the next week or so ill get a full service of everythign and see what hapens form there, i appreciate the help guys thanx heaps!

[R31Heaven]

My nics has a simular problem it tends to misfire & be laggy while cruising when cold, as soon as the motor warms up and the temp needle hits the fist line on the gauge it takes off and is fine. I have, changed ECU temp censor, O2 Sensor, just had the AFM Calibrated wich fixed my over fueling problem as some one had dicked with it and was way out. I have just replaced my ECU and it seems to not be laggy when cold but splutters a bit more when cold but can put that down to still learning. this has been a quest over the last 12 months and will not be happy until it purs.

[WLD747]

Well guys told you i would keep you posted on the remedy for our poping in RB25s. Ive been told possible problems coils, ignitor module, pod etc. Well i went to autobarn in my area(sunshine), ask the guy if he had a really good injector cleaner thinking i might have an injector problem. Well he said try Pro Strength Octane Booster (NULON) for $20. The reason he told me was it cleans the bad deposits on the injectors, increases performances and horsepower. Well once the octane boost kicked in any car on the road will have no chance. It holds boost and keeps on boosting.

Hope it fixes your guys problem, fixed mine; touch wood.

Cheers

AK

[AutoTrust]

Another interesting point is that japanese fuel is better octane than any aussie fuel, so an octane booster may fix the problem but if it comes back next tank of fuel then altering the timing, as has been suggested, would be a better long term solution.

[slow_r31]

just a thought

Doesn't the rb25 ecu have knock sensors? Maybe this extra boosting is causing unheard detenation that the ecu is picking up, thus pulling back the timing?

[WLD747]

i think the octane boost has run out and im back to square one. Coils and Ignitor module next.

anyone got an idea?

cheers

ak

[R31Heaven]

If octane boost worked, I would be cvery suss of the fuel you are using

[Mase]

what petrol are u using wld747

[AutoTrust]

Get a dyno tune, and run BP Ultimate or Mobil 9000

[WLD747]

im running mobil 9000 now and still same problem. Must be coils.