Rb25det Problem

[_MRR33]

Hey fellow SAU members ,

I recently had a misfire problem in my RB25DET, I wasn't too sure what the problem was, however I asked a few people on SAU what it could be, and I ended up finding out it was a broken tip on the 6th cylinder spark plug.

Thank god, the tip had just melted itself away. The plugs I was using were $25 each, the NGK ones at the time. After finding the problem I changed all 6 spark plugs to the cheap-0 type ones which are $3 each.

The car has been running fine, no problems - however now I have noticed the same problem has arisen again, and I am more then sure it is the spark plug again.

I'm not too sure why it is doing this, anything you guys can think of?

Maybe I had bad luck with that one NGK spark plug, and now since the cheap-0 ones are in there it can't handle the spitfire coil packs and is causing them to melt again?

I'm off to work shortly, so I think I'll pull it apart after work and have a look, but like I said before I am more then certin it is the spark plug again, cause it's doing the exact same thing - that was - it had a missfire / popping noises at 4000RPM+ on high load.

So, anyone who has any ideas please do leave them here as I want to fix the problem as soon as I can.

Engine / Car

- Nissan Skyline R33 GTS25T 1993 Series 1 RB25DET Forged 2.6L

Modifications:

- K & N Pod Filter

- Cold Air Intake

- Forged Pistons

- Strengthen Conrods

- Blueprinted

- Balanced

- Port Polished

- Metal Head gasket

- Spitfire Coils

- High Performance Timing Belt

- High Performance Spark Plugs

- Gready Turbo Timer

Everything else, engine wise is stock. Stock ECU, Stock Boost etc - all modifications are listed above.

Thanks for your help!

[jeffworld2]

your car should not be burning off plugs, either they are the wrong heat range by a long shot or you are getting detonation from too much timing advance.

with splitfires you should be able to run a gap anywhere from 0.8-1.1mm without much trouble, with ngk heat range 5/6.

try putting in a set of BKR6EYA spark plugs, a whole set will put you back about $16. put them in and check the timing, if it still burns off, you need a tune, as your a/f is not in tune with the ignition advance.

what ecu have you got? if your running a 2.6 now, it wont be fuelling it enough on the stock ecu. you can't run a bigger engine from a smaller ecu

[markimak]

what ECU have have. whats the knock value. u getting pinging?

[jeffworld2]

its stock ecu, thats the problem markimark. i was just coivering all bases

[RB30-POWER]

get your injectors flow tested and check your timing.

[markimak]

prob timing bro.

u cna adjust it on ur cam pulley if u feel handy..

goodluck with that.

what power u making with it. and what u want to push out of it being forged and all..

[_MRR33]

I fixed the problem, I knew it'd be the spark plugs. I changed them to the $25 NGK ones, and I haven't had a problem, so I'll take it for a drive tonight and see how it goes.

Just to answer people questions..

what ecu have you got? if your running a 2.6 now, it wont be fuelling it enough on the stock ecu. you can't run a bigger engine from a smaller ecu

It was running fine before, when I got the car rebuilt with Forged pistons, I was told it would be fine.

what ECU have have. whats the knock value. u getting pinging?

Stock ECU. Nah, no pinging.

get your injectors flow tested and check your timing.

That was done recently. Timing however, could be a problem.

prob timing bro.

u cna adjust it on ur cam pulley if u feel handy..

goodluck with that.

what power u making with it. and what u want to push out of it being forged and all..

I've had the car about 6-7mts, and it's cost me a bit since, Forged Rebuild etc, also got it kitted and the interior done, so at the moment just laying back want to get a set of 18inch deep dish chrome wheels though.

In the long run, I may be looking at a bigger turbo, injectors, upgraded ecu etc etc.

THANKS YOU VERY MUCH TO ALL THAT HELPED!

[HRthirtyone]

ok so your computer is factory programmed for 2.5 litre engine, supplying it with enough fuel for 2.5litre engine, until under WOT, boost aand high rpm, the 2.6 bottom end will be moving a lot more air. with the standard fuel... get it on a dyno. it should NEVER melt plugs!!!

[gtst4d]

I second HRthirtyone, get it on the dyno to check the air fuel ratio, if anything just to be safe because if they are bad all the money you spent on the rebuild will be wasted.

ps forget the weels and get a computer for the car.

[markimak]

GL with it...

PFC will be fine for it.

[fcruz3r]

had the same probs on my 1.6 vtec civic....turns out the previous owner had already done a overhaul and i think it had overheated previosly and warped the head...so they skimmed the head a lil too much and i was running too high compression....would go through a set of plugs in 4k ...and platinums would only last a lil longer...maybe 15k max