R33 Gtst S1 Missfire Plz Help

[KnightRiderR33]

Hey guys ive been having this problem for a lil while now but im getting close to fixing it. Ive first replaced my plugs which were PFR5G-11 with a 1.0 gap and i still got splutering so i changed the gap to 0.8.. still the same. i cheked the coils i found no cut or anything that could lead to arching but i taped it up anyway just to be sure and still i got no change.. Today on the otherhand i learned that i should be running BCPR7ES plugs they are better. Apparently the platnium plgs do not like BOOST so upon changeing to these plugs i noticed it doesnt splutter as much im still missing coming onto boost but its not as bad as b4. The BCPR7ES plugs come with a 0.75 gap out of the box if i were to regap to 0.70 would this fix the miss? what do you guys think?

[karma_syke]

it still might be your coils, you can't see the micro splits in the coils, or the coil packs might be shorting internally (in that case there is nothing you can do). i had the typical 5000rpm "pa pa pa pa pa" my first instinct was the spark plugs but by doing further research on the fourms i looked at the coils. Eventually i coated the coil packs in a few layers of silicon ( the stuff you can get for roofing ) its a perfect insulator, sticks to the plastic and resists heat extremely well. long story short, no more missfire.

will be up for new coil packs eventually but this might help. silicon from bunnings ~$10

[lachlanw]

borrow known good coils form someone

[KnightRiderR33]

OK so im looking at ebay and there are a set of 6 S2 coils from a 97 skyline will they fit? im only looking because the coils would be 13 years old better then 16 lol and its up for bidding should i try i realy dont have the 350 - 400 bucks atm for new yellow jackets

[mad082]

series 2 coils are not the same as series 1. also don't be cheap. buy new coils not second hand as there is nothing to say that they won't also have the same issue. gapping down plugs is simply a band-aid fix to a bigger problem.

since you car is a series 1 it could also be the ignitor pack causing the issue. that is the box at the back of the rocker cover.

finally, unless you are running high boost on (16psi or higher) then heat range 7 plugs would be too cold. you would be better off running BCPR6ES plugs. they are a hotter plug so won't suffer from fouling up at idle, etc like the colder plug might.

[KnightRiderR33]

series 2 coils are not the same as series 1. also don't be cheap. buy new coils not second hand as there is nothing to say that they won't also have the same issue. gapping down plugs is simply a band-aid fix to a bigger problem.

since you car is a series 1 it could also be the ignitor pack causing the issue. that is the box at the back of the rocker cover.

finally, unless you are running high boost on (16psi or higher) then heat range 7 plugs would be too cold. you would be better off running BCPR6ES plugs. they are a hotter plug so won't suffer from fouling up at idle, etc like the colder plug might.

Come to mention it ive hooked up my boost gauge and found that im cutting out at 15psi which ive been told is high all that i have on the car that i know of is an intercooler and a full 3" exhaust. Ive been told to adjust the acctuator to lower the boost and i was just outside having a look and found that the standard acctuator does not seem adjustable.. hmm how can i lower the boost i have no boost controller and is 15 psi normal? i thought 10psi was normal.

[KnightRiderR33]

bump** anyone ?? lol

[widebody180]

Is the boost gauge your using actually accurate? Could be a number of reasons your boost is high. Might be a split in the line going to the stock solenoid etc. As for the misfire, the Nissan ignition modules are rubbish and have a tendency to break down after a while.

[KnightRiderR33]

Is the boost gauge your using actually accurate? Could be a number of reasons your boost is high. Might be a split in the line going to the stock solenoid etc. As for the misfire, the Nissan ignition modules are rubbish and have a tendency to break down after a while.

are they expensive? the ignition moduels?

[mosquitocoils]

Could you be overboosting and hitting 'rich and retard'?

[mad082]

as someone said in reply to you in another thread, it sounds like you have some sort of boost controller. try running a new hose to the wastegate (straight from teh cooler piping to the wastegate actuator) and see if that alters the boost. if not then you may either have an aftermarket actuator or the wastegate flap is fouling on the dump pipe.

[ClutchBurndout-:(]

havnt read whole thread, but change your coils, i had same issue, splitfires fixed everything

[KnightRiderR33]

Hey guys its all good now thanks for the info it turned out to be an over boost problem due to the incorect setup of the acctuator i took it to autotech in granvile and found that the actuator was not hooked up to the plenum it was just running to the BOV return valve apparently this is comon these days they call it a ticking time bomb. Some idiots out there when they sell there turboed cars especialy skylines to new owners puposely set it up to over boost and in due time of driving the turbo and engine will fail i got lucky..... IM URGING ANY PERSON WHO IS THINKING ABOUT BUYING A SKYLINE OR ANY TURBOCHARGED CAR TO TAKE A GOOD LOOK AT THE SET UP MAKE SURE THE ACCTUATOR IS HOOKED UP TO THE PLENUM MOST NORMAL MECHANICS WONT REALISE THIS SO I THOUGHT ID LET U KNOW JUST INCASE THE WORST HAPPENS.. BY THE WAY I GAVE THE SELLER AN EARFULL PROBABLY WASNT WORTH THE ENERGY BECAUSE HE DENIED IT HE MAY NOT HAVE KNOWN BUT SERZ UD REALISE SUMTHING WRONG AFTER HAVING IT FOR SO LONG ID LIKE TO THANK YOU ALL FOR YOUR INFO BECAUSE I DID TRY ALL THESE TRICKS U GUYS TAUGHT ME AND IF I DIDNT I WOULD NOT HAVE RESOLVED THIS PROBLEM AND U GUYS SAVED MY ENGINE LOL TC

[Trev]

havnt read whole thread, but change your coils, i had same issue, splitfires fixed everything

What this guy said - Splitfires are the cure for 90% of misfiring Rb25's.

[mad082]

Hey guys its all good now thanks for the info it turned out to be an over boost problem due to the incorect setup of the acctuator i took it to autotech in granvile and found that the actuator was not hooked up to the plenum it was just running to the BOV return valve apparently this is comon these days they call it a ticking time bomb. Some idiots out there when they sell there turboed cars especialy skylines to new owners puposely set it up to over boost and in due time of driving the turbo and engine will fail i got lucky..... IM URGING ANY PERSON WHO IS THINKING ABOUT BUYING A SKYLINE OR ANY TURBOCHARGED CAR TO TAKE A GOOD LOOK AT THE SET UP MAKE SURE THE ACCTUATOR IS HOOKED UP TO THE PLENUM MOST NORMAL MECHANICS WONT REALISE THIS SO I THOUGHT ID LET U KNOW JUST INCASE THE WORST HAPPENS.. BY THE WAY I GAVE THE SELLER AN EARFULL PROBABLY WASNT WORTH THE ENERGY BECAUSE HE DENIED IT HE MAY NOT HAVE KNOWN BUT SERZ UD REALISE SUMTHING WRONG AFTER HAVING IT FOR SO LONG ID LIKE TO THANK YOU ALL FOR YOUR INFO BECAUSE I DID TRY ALL THESE TRICKS U GUYS TAUGHT ME AND IF I DIDNT I WOULD NOT HAVE RESOLVED THIS PROBLEM AND U GUYS SAVED MY ENGINE LOL TC

so which line was the wastegate hooked up to? the bov line that simply vents back into the intake, or the vaccum line from the plenum to the bov? if the plenum to the bov line then it will still work fine and isn't really an issue. you may get the occasional spike, but i was running my car like this for a while and never had an issue with it over boosting (just the occasional spike for half a second on a gear change). also the fitting instructions for hybrid intercoolers tell you to hook it up the the vaccum line of the bov.

that said, i found that having the wastegate hooked up to the plenum a bad idea full stop. it would suffer from spiking. also the fact that the actuator is reading from after the intercooler isn't that good either in my opinion. lets say for example that at 12psi your intercooler is adding 2psi of restriction. if your wastegate is reading from after the intercooler, your engine is still seeing 12psi but the turbo is actually putting out 14psi. this is going to drastically shorten it's life. if you have the wastegate reading from the intercooler pipe from the turbo to the cooler then the turbo will only run at 12psi, however your boost gauge will show the boost dropping off at higher rpm at full throttle. this might make you feel like things aren't working properly, but it is a good way to see a mix of the turbo running out of puff and how much on a restriction the intercooler is.

once i changed my setup back to getting boost from before the intercooler my boost was much more stable than when it was hooked up to the plenum.

[karma_syke]

mad082, my brain hurts, i just had a look at the instruction manual for turbosmart boost controlers, and they say to have the pressure source BEFORE the throttle body, which is inline with what you said...

however

if you have the pressure source coming straight from the plenum (after the throttle body) wouldn't that be the worst source of pressure available? soon as you close the throttle plate a vacuum will be created, and after you start to open it again, the pressure would do all sorts of wierd things given RPM/how open the throttle is/ and the areodynamics of the plenum... the controler wouldn't know wtf is going on (maybe cause of spiking?).

wouldn't the ideal source be just after the turbo, idealy as close as you can get it?

[mad082]

mad082, my brain hurts, i just had a look at the instruction manual for turbosmart boost controlers, and they say to have the pressure source BEFORE the throttle body, which is inline with what you said...

however

if you have the pressure source coming straight from the plenum (after the throttle body) wouldn't that be the worst source of pressure available? soon as you close the throttle plate a vacuum will be created, and after you start to open it again, the pressure would do all sorts of wierd things given RPM/how open the throttle is/ and the areodynamics of the plenum... the controler wouldn't know wtf is going on (maybe cause of spiking?).

wouldn't the ideal source be just after the turbo, idealy as close as you can get it?

in my opinion, yes. you want it to be a few inches from the turbo outlet so that there isn't going to be turbulence (so having it on the compressor housing like some turbos do isn't the best place). you also want the hose to be as short as possible as this minimises the amount of flex/expansion in the hose. having it in the plenum isn't ideal as the flow of the air will actually create areas with higher and lower pressures. it's not like a ballon where once blown up the pressure will be equal everywhere, areas in the direct path of the airflow will have a higher pressure than areas where there is turbulence and not as much airflow.

[karma_syke]

i had a quick look at my boost controler set up, the pressure source comes from a nipple on the turbo side of the cross over pipe, considering this is past the FMIC i wonder how this affects the relative pressure and subsequent boostcontrol regulation. My boost guauge source comes from a nipple on the plenum itself, again i wonder how accurate the readings are. it could be +/- 1,2 or 3 psi...? if so that could be significant.

Actually come to think about it soon as the air passes through the throttle body it goes from a ~3 inch pipe to a much larger space, simple physics tells you that there will be a pressure drop, so if infact your boost gauge says your boosting to 10psi and the source is from the plenum, then the pressure in the pipes could be significantly higher. Thus you are running your turbo harder than you intended...