Rb25Det Flat Spot In R31

[ianga]

Hello Guy i have a rb25det in my r31 and i have a flat spot between 4000 - 5500 rpm then it picks right back up again. now i have done a search but couldnt find what i wanted

car is running 11psi

plugs have been changed and regapped to suit more boost.

has a little miss at idle and sits around 500-600 but once around 1000rpm its fine.

stock ecu

checked timing

i am going to rev zone and putting it on a dyno in a few weeks not much they can do with a stock ecu tho.

any help on this problem would be great

Cheers Adam

[Dobz]

Try winding back the boost and see if that changes anything.

From what I inderstand rb25 ecu's can be a bit touchy when winding the boost up.

Edited August 30, 2011 by Dobz

[ianga]

also got a walbro pump

[ianga]

i will try wind the boost down to to 9-10psi atm its goes to 12 and backs off to 11psi

[Don Dada]

Do a search on rich and retard you'll get plenty info

Turn down the boost

[GTScotT]

The boost is the first thing to check, put that back to 8 or 9 as stated.

The other thing is to make sure ur VCT is working.. A search will bring up a few threads about testing VCT.

[Room42]

The problem is the stock ecu. Get a power fc or better still a mafless ecu and put it in. Dont worry about taking it to the dyno yet, its a waste of money. Put that cash toward your new computer. It will feel like a new car once the computer is in and tuned. Your car will have about 150rwkw give or take.

[ianga]

i turned the boost down to 9psi, cleaned the acc valve. idles smooth as now but still have a little flat spot.

[Room42]

  On 31/08/2011 at 4:47 AM, ianga said:

i turned the boost down to 9psi, cleaned the acc valve. idles smooth as now but still have a little flat spot.

Yeah mate they all do it. You cant do anything about it till the ecu is swapped over or piggybacked.

[RB25 SKYLINE]

sorry to hijack but i have this same type of problem and have heard that the apexi safc is the cheaper solution but not sure if thats true