MSefi.com read only forum (Jan.15,2018)

I have a throttle body set up with 4 85lb injectors on a Chevy 350. I have got it to run but with this size injector I would not think i would have ve values as high as i do. At idle i have to have it set at 60 and at full throttle the values are high 90s. The motor it is currently on is only around 250 hp and i was trying this set up because it is going on a much higher hp motor but with this set up there wouldnt be enough fuel but these injectors should support at least 500 hp. When i put a noide test light in the injector plug it seems real dim. I was wondering if anyone has had issues like this with ve that is way to high

drz712,

The VE values are dependent on quite a lot of things, like opening time, req_fuel value, etc. So you can't go by peak VE values very much. Instead, judge this by the injector's duty cycle (DutyCycle1 in a datalog). As long as it stays below ~90% you are fine and have a bit of a safety margin.

The PWM required for low impedance injectors will make a test light look dim under most circumstances.

FWIW, I have run 4 85lb/hr injectors (Holley 900cfm TBI) on my 435 horsepower 406cid small block Chevy (with ~22% PWM, and 0.7 for both opening time and PWM time threshold), and it worked just fine with a fair bit of a margin on the duty cycle.

Lance.

Thanks for the response. I forgot to say that these are high impedence injectors. So i am not running any pwm. So if the ve is 99 the duty cycle is not actually 99 is what your saying? I did also notice when i shut down the motor the noide light gets bright like when in injectors on a facorty ecu for the last several pulses

I looked at a lot of stuff on here and see that duty cycle and ve are not the same. I see that I can bring my ve down by adjusting required fuel. But even with this the noide test light seems dim with no pwm. Anyone have any ideas on this