Good Ol' Skyline Bad Power Delivery

[sholm23]

Hi Guys,

My skyline is playing up again and after trawling this site and google i can't find an answer which is unusual. So, awhile back i posted a read about my car not making full power on WOT and it was making the most power (half what it should) at half throttle. I got that problem fixed and it turned out to be a shagged fuel pump, It's now got a Bosch 040 and it had so much more power.

In RWD it would put me back in the seat and felt like ~170+kw...It hit what i think is R&R at 6500rpm in 2nd, 5500 in 3rd and 4500 in 4th etc. Basically it would hit this point (when full throttle) and cut power and throw you forward. Thats all fine because i put that down to needing a tune. Its got an RB25 turbo on an RB20DET with 10psi. Stock ECU.

Problem:

The car only gets driven (and shortly) every 2 weeks or so... last week i took it for a spin and say when your in 2nd gear and hit full throttle, its normal off boost, then when it hits full boost it feels the same... it's holding back like the brakes are on. It hits like 5200rpm and power comes back and it launches until it hits the previously mentioned R&R. Along with this new problem it also missfires a little when you change gear and hit the accelerator again.

Mods include, Pod filter, FMIC, RB25 turbo, Bosch 040 fuel pump, BCPR7ES 0.8mm plugs, all filters have been replaced. Sorry for the long post but hey, the more history and back story the easier it is to diagnose the problem.

I might also add (completely unrelated) i replaced the oil pressure sensor this arvo and holy hell is that a mission!!! I had the old sensor unplugged but still screwed in for awhile, would that cause an oil leak? Engine is leaking a fair bit of oil only recently somewhere from that side of the engine.

Hopefully someone can help I love my skyline when it works....

Edited November 17, 2010 by sholm23

[Moodles2]

I would first confirm the pump is running at alternator voltage not the factory 6v/12v switching setup as aftermarket pumps weren't designed to run at such low voltage.

[sholm23]

Wired up the fuel pump properly this morning. Makes a nice whirring sound to 14V+.. Problem is still there.

Car has ZERO power most of the time, came round a corner in 2nd gear (3000rpm) to get up a light hill and it just couldn't. Power seems to be all over the place but only works ok (when it does) at higher RPM. Just putting a long in 2nd/3rd, 3000 ish rpm, put your foot to the floor, it gets full boost and it might as well be tied to a post in 6th gear.

It then decides to go and chucks you way back in the seat until R&R, change gear and theres a bit of missfiring and stuttering as it decides what to do and then maybe some power for a brief moment.

I had a look at one of the spark plugs and its BLACK as, so i think it's what i originally thought, bad coil packs? I could change spark plugs but i've tried 4 sets in the last 2 months so i rather not. Plugs are BCPR7ES, could probably go with 6's but i had them before when it did work and they started to melt.

So, Fuel shouldn't be a problem, New filter, Bosch 040 with correct voltage. Boost should be ok too as the guage (aftermarket) is reading 10psi with an RB25 turbo. Boost comes on when it should etc. Ignition is where i think it's falling apart. Plugs are (as above) black like it's not burning the fuel but there were ok before. Coil packs are 21years old and there's miss firing sometimes... Will any Ebay "performance coils" that fit, work? I know they probably won't last as long as split fires, but will the do the job?

Please help!! Any recommendations of what to do next will help, I simply don't have the coin to throw at it to replace everything and i need it running before Christmas.

Edited November 20, 2010 by sholm23

[sholm23]

I'm in Brisbane. Where would be the best place to get NIStune installed and dynoed? I'm going to go the full tune sooner rather then later.

I was holding off getting it done because if i have problems with my car i don't want to be doubling up on dyno hours but i think getting it installed and the AFR's checked out at a minimum would be good.

Starting to think hitting R&R too often and not enough long km's has built up too much unburnt fuel on the plugs. Which would explain all of above. Might clean my plugs and see if that's it. I hope it is because after NIStune i should be a proud 180kw GTS-4 owner

Any theories? Also all dyno tuners feel free to PM me regarding NIStune or a similar ECU options for a basic tune.

Wish i could edit the title to something more appropriate... guess that comes at a higher post count.

[Rolls]

I'm in Brisbane. Where would be the best place to get NIStune installed and dynoed?

Email them themselves, they would be able to give you information towards the better tuners up your way.

[DVS JEZ]

It sounds like an ecu issue. A nistune or aftermarket ecu will fix the issue.

There is no r&r then

[sholm23]

Yeh i'll shoot off an Email to NIStune themselves and a few tuning shops...

Any recommendations to who does quality work in Brisbane? Surely there's got to be a Nissan specific tuner. Mercury motor sports springs to mind?

Edited November 24, 2010 by sholm23

[sholm23]

FIXED!!!!!!!!!

Put in some Yellow jackets this afternoon and cleaned up the (really rich looking) spark plugs. Car now boosts perfectly all the way upto an unusual non-existent limiter. NO R&R on 10psi... Feels good too, a tiny bit of hesitation in the mid range but that would most likely be the stock tune+bigger turbo.

Car has more then enough power for me in 2WD and 4WD to start out on and from here its more boost + Tune at Mercury Motorsports.

Also "Performance wise" are terrific, I bought the coil packs Saturday and they arrived here today, that's overnight from NSW!! Good price too.. definitely recommended.