Rb26 Trouble

[RB26TTVL]

Just recently changed an AFM and the o2 sensor in the inlet manifold which were giving me trouble, I found another problem. I have good power in the first three gears, but can't make power above 4000 rpm in fourth and fifth. Thought it might have been fuel, so I inst. an 044 bosch and surge tank, but no help there. I live in the country and its at least an hour drive to any workshop who can help

Has anyone had any trouble along this line.

Thanks

[TTT]

injectors?

fuel pressure?

[RB26TTVL]

injectors?

fuel pressure?

Injectors are standard GTR, and fuel pressure appeared to be fine, ie, pressure doesn't drop when power drops.

Before I changed the afm and O2 sensor, it ran fine, aside from coughing out with the dodgy afm every now and then.

[R31Nismoid]

What you mean doenst make good power?

ON a dyno?

doesnt feel like its making power?

could be soo many things its really hard to tell.

Does it splutter?

Mis-fire?

Got an aftermarket boost gauge? Whats it doing in 4th?

[blind_elk]

...the o2 sensor in the inlet manifold...

??????

Any errors showing up from the ECU? When was the last time you had the injectors cleaned? How is the ignition timing? What boost is it running?

[RB26TTVL]

Running around 12 pound of boost.

In terms of power being made, just as it's coming on to boost in fourth and fifth it's not following through. Very happy to sit at about 4000rpm, but will go no further. Fuel pressure doesn't drop, boost doesn't drop (aftermarket gauge), they just don't continue to climb. In 1,2 and 3rd, it will make 12 pounds and 8000rpm no worries.

The injectors haven't been cleaned since I've had it, but until this I've had no indication that they might be dirty at all. Can it happen so suddenly as to cause this?

Sorry, not O2 sensor, I think it is air temp sensor in Inlet!

[R31Nismoid]

Cleaned the AFM lately?

[GTRsean]

180 klm speed cut???