I don't know what else to do.. VTEC is set at 6000 RPM. My motor runs rich and strong all throughout until Vtec kicks over. Then it goes immediatly lean and power falls on its face. I have the V-AFC set at +15-20 to see what that did. Also have Holley 190 LPH fuel pump. Fuel pressure is set at 50 psi with the vacuum line on. I've installed new O2 sensor, changed MAP sensors, checked timing and ran 3 different computers. If the car has been sitting for a while and then I get on it, it screams up to 9000 RPM (running rich) with no problem. If I try to do it again, it runs lean. If I stay on it when vtec come on, from 6000 to 7000 RPM, it's lean; 7000 to 7800 (rich), then back to lean from there on.. and I never have taken it up to 9000 just because I don't want to damage it. I am running a P72 ecu with the G-Force engineering chip with a revlimit @ 9300 RPM.

Was working fine for a month since the motor was built with the following:

B20B with Endyn pistons, eagle rods, Si ported/polished head, skunk2 cams, ITR intake manifold, jdm itr header, vafc, fuel pres. regulator, light flywheel, underdrive pulleys, stock fuel pump, and chipped ecu.

After motor started messing up, the following was added or replaced:

Holley fuel pump, new O2 sensor, replaced map sensor.

What else could it possibly be?? Any ideas?

 

Dirty fuel filter?

 

stock fuel maps still? I believe that the GSR fuel maps are somewhat lean, at least thats what I was told.

 

Nope.. can't be that.. because with the same setup, I drove it for over a month with everything working. Even ran it at the track and ran 13.6 and it was running strong. So there's got be something else.

 

change the fuel filter, throw in some injector cleaner . And how do u know u are runnin lean? your a/f gauge???
manny

 

yes my a/f guage...

 

your other choice is to run a cutom hondata chip or trying the another chip, at WOT, ECU relies on preset maps, therefore either the g-force wasn't setup properly or you have simply too small of an injectors
for the setup you're running you need at least 270cc or 310cc injectors...
as VAFC can take care of some fuel but only by increasing the duration, not actually flowing more...

 

Okay lets clear some things up:
First Check if your air/fuel gauge is wired correctly. The proper way to tune the car on the street is with a volt meter/egt gauge and checking the plugs on the regular. Also, a bigger injector is always good with a setup similar to yours. I really think that your car is not running lean and that the autometer air/fuel gauge is garbage.
Second what is your timing set at? What type of plugs are you using? Do you have an ignition? Are you throwing any codes? Did you try a stock ecu?
Many factors to play with but stock injectors can support a good 200 na motor.

EVIL

 

Yeah stock injectors are the bottleneck. I can attest to that. Im running JUN III on 12:1 compression, I was using stock injectors and my fuel pressure was at 54 psi with the vacumm line on, and it still wasnt enough..bigger injectors. I was told to get 440 injectors.

 

I understand about getting bigger injectors and all, but.... It was working fine for over 1500 miles... then all of the sudden, this. The car has to be running lean, I can feel it. When it runs good, it runs strong all the way up to 9000. But, you can feel it when vtec kicks over, you can feel the car bog down really bad.. and the light pegs red as it slowly creeps up in RPM from there.

The timing is set at 16 degrees advanced. NGK-R plugs. Stock ignition. No codes being thrown. Tried stock ecu, gforce, mugen and skunk2. No difference.

 

change the fuel filter.

 

Okay, replaced the fuel filter. Same problem.

 

Go to a dyno with a wide band o2 sensor, and get a proper reading.

 

you might want to pop your injectors out and have them cleaned, and flow tested.