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Rb 25 Spluttering Problem.

kjb_r33

By kjb_r33,
in Engines & Forced Induction

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kjb_r33 Experienced

kjb_r33

Posted
Posted

Having a problem with a mates series 2 r33.

Engine runs fine unloaded, can free rev to 7 grand with no problem but once its loaded up its starts spluttering.

Is hitting around 9 psi of boost with no problems, but it feels like the its not going anywhere, or even that the brakes are being applied.

No fault codes show up, and with a scan tool plugged in everything seems to be where its supposed to be.

Tps: good through whole range.

AFM: .5v keyon engine off, just over 1v at idle and good transition through rev range

stable rpm so CAS seems ok.

Things that have been tested.

Coils swapped over with a known good set.

News plugs, gapped to 0.8 mm

Tried a different afm anyway, no different.

Checked exhaust back pressure to make sure exhaust isnt blocked (removed and checked cat as well)

It actually does feel like a blocked exhaust but it hits no more than 5kpa, 20 kpa being the limit.

checked fuel pressure and flow, all good.

Compressor wheel and turbine are all intact, spins freely with minimal movement, waste gate opens and closes as it should (checked with pressure regulator from my compressor).

Engine is basically stock, just has a rb20 wastegate actuator and FMIC. Was running fine, problem started all of a sudden, not gradually.

Sort of steering clear of CAS because it does free rev with no problems.

Any help or ideas would be appreciated.

Thanks.

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700HP-GTR33 Mentor

700HP-GTR33

Posted
Posted

Hello,

I am leaning more to injector or fuel problem.

Reset the computer and if that does not fix it......use heaps of injector cleaner

in you tank.Check also you fuel filter.

If this does not fix it...your fuel pump could be on the way out...I know you checked..

but could be having problems at high load.

Cheers and good luck. :)

kjb_r33 Experienced

kjb_r33

Posted
  • Author
Posted
Hello,

I am leaning more to injector or fuel problem.

Reset the computer and if that does not fix it......use heaps of injector cleaner

in you tank.Check also you fuel filter.

If this does not fix it...your fuel pump could be on the way out...I know you checked..

but could be having problems at high load.

Cheers and good luck. :)

Computer has been reset, he had actually tried another ecu as well. After running it it seems to be running rich more than anything, ive checked o2 sensor output while its doing the spluttering (using scan tool) and its reading very rich, plus you can smell the fuel.

700HP-GTR33 Mentor

700HP-GTR33

Posted
Posted
Computer has been reset, he had actually tried another ecu as well. After running it it seems to be running rich more than anything, ive checked o2 sensor output while its doing the spluttering (using scan tool) and its reading very rich, plus you can smell the fuel.

Injector leak or fuel rail leak?

kjb_r33 Experienced

kjb_r33

Posted
  • Author
Posted
Injector leak or fuel rail leak?

Other than maybe an internal injector dribbling, there is no external leaks. Thing idles smoothly, runs great upto redline with no load. Even disconnected regulator hose to give it full rail pressure and and it still idles smoothly.

As i said earlier, it started doing it suddenly.

Thanks for the suggestions.

kjb_r33 Experienced

kjb_r33

Posted
  • Author
Posted

Found the culprit. All the fmic hoses were tight but the torque reaction of the engine was pulling a hose off when on boost. when engine relaxed again hos was popping back one. One of the pipes apparently had to be cut to make it fit so there is no flange/rib on it.

Thanks guys.

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