2500 rpm bucking
 

For some reason any time I cruise lightly through or at 2500rpm the ecu is cutting fuel. It causes the car to buck. I've been over all the sensors and just installed a new o2 sensor which cleaned up the driveability quite a bit however I can't seem to get rid of this one spot. I have no emmissions, it's an s4 t2 ecu w/2.0. Did the same thing with 3 different sizes of injectors. The engine is streetpported on the intakes and slightly larger than a rb sp on the exh ports. Also removed the 2 throttle plates and ported the tb however the problem was there before I did any tb mods and didn't change. I'm also using the stock na harness, don't know if that could effect it?

Brent

are you talking about the problems seen here?: https://www.rx7club.com/rtek-forum-168/help-log-please-637080/

i still have the same problem, its really weird. it seems to have gotten a little better since then, but i havent changed anything ?? it almost feels like a bad tps, but when i log the tps, it is smooth from 20% to about 85% at wot

Mine seems to have cleared up. Not 100% but its definitely gotten better now that I put the new alternator and o2 sensor in. Seemed to take a bit of driving to sort itself out? Doesn't make sense to me but I'll take it.

did you change yor secondary staging rpm ??

i just thought of this.. isnt the fuel pump on some kind of resistor?
if so could it be going bad or have a bad spot in it so that at this certain voltage(cruise) it doesnt send currect voltage to fuel pump?
or have you check your fuel pump?

I will look into my rfuel pump elay tomorow.

im running on a walbro 255, which is powered on its own relay straight from a 12v source. so no resistor relay inline anymore

it seems the problems only started happening after i installed new RC injectors. but its weird that it only happens under certain cruise conditions, not at idle, not at wot, not under boost, etc. if it was the injectors or wiring or clips, wouldnt it happen all the time?

I changed all my clips to bosch clips.

i also have the walboro 255 and my secondarys are rewired.
also redone the ground under the TB
my injectors are new..
i would like to rewire my fuel pump but im not confident enough in myself to rewire it... but im willing to try to fix this issue.