Jump to content
SAU Community

Why Are My Injectors Hitting 100% Duty Cycle?

zinkrb250

By zinkrb250,
in Engines & Forced Induction

 Share

Recommended Posts

zinkrb250 Enthusiast

zinkrb250

Posted
Posted (edited)

SII rb25det

-using power FC-

Can't figure out why my nismo 555cc injectors are hitting 100% duty cycle when i'm only making 371horsepower... any ideas???

-Duty cycle is set at 66.5% at .14m/s lag

-Fuel pressure is set at 43psi w/o vacuum

-Brand new fuel filter

Edited by zinkrb250
R31Nismoid Grand Master

R31Nismoid

Posted
Posted

You have a walbro fuel pump i bet

*reads sig* Ah... thought as much

Exactly same problem i had :P

throw it in the bin, or get a surge tank and use it as a lift pump... about all they are good for.

zinkrb250 Enthusiast

zinkrb250

Posted
  • Author
Posted
You have a walbro fuel pump i bet

*reads sig* Ah... thought as much

Exactly same problem i had :P

throw it in the bin, or get a surge tank and use it as a lift pump... about all they are good for.

So you were using a walbro fuel pump and reading 100% duty cycle?... I don't understand how a failing fuel pump would make the powerfc read 100% duty cycle... could you please explain?

saliya Rising Star

saliya

Posted
Posted (edited)

Hey,

put a fuel pressure gauge on your supply line and see if your pump's running out of flow (you will see fuel pressure follow

boost initially, then fall off _before_ boost if the pump runs out of flow).

If you can borrow one, this will tell you a) straight away and b) cheaply if your fuel pump is the culprit.

edit: of course, you need to do this on a dyno or on the road (you're interested in fuel pressure at high rates of flow,

not at idle).

Regards,

Saliya

Edited by saliya

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Komdotkom
      High temp brake fluid?

      By Komdotkom · Posted

      Reasonably hard, although I haven't run it with the new Endless setup yet. The old brakes were F50's on 335mm rotors and the car did a 1:40.6 at Phillip Island which is a reasonable time, I'm seeing high 600s on the temperature paint. A guy I know ran the Endless fluid at WTAC without issues and he was doing 1:33's I think (Evo) with a 355/332 setup. I don't get out to the track as much as I'd like but we put the car on the hoist and spanner check every bolt and re-paint mark everything, bleed the brakes, change the fuel, check the coolant system and re-bleed blah blah blah before every event. Motorsport is expensive, RB's are expensive so a couple of hours before an event is time well spent. It's also a net time saving because if you can keep your RB from self destructing it saves you time in the long term!
    • Duncan
      First/Second Post

      By Duncan · Posted

      Welcome Alice......hope you have a bit more luck from here on! What was done in the build?  
    • svenskalice
      First/Second Post

      By svenskalice · Posted

      Hello! I'm new here, I have an R33 GTST that is currently being finished up! Last year was pretty rough, blew two stock turbos so I decided to build the car. Has been down since November, but I get it back next weekend!
    • svenskalice
      Kaizo Industries

      By svenskalice · Posted

      Hello, I believe my car was imported to America in the 2000s by Kaizo Industries. Would anyone be able to help me find more info on them? I've only found all the basic stuff like that paul walker bnr34, them being shutdown by feds, just stuff like that. Any help would be much appreciated, thanks!
    • believer
      HKS Vcam Step Pro Issues

      By believer · Posted

      I am using Motec M150.  I am not working on the car myself actually.  My workshop is giving all these info, they are quite reputable in the industry and are very familiar with Motec and RBs and have done a few big setups with VCam and single turbo on RBs.  In fact, they built and tuned my engine from day one.  But they are stumped with my engine at the moment and cannot work out how come the compression is so low with the VCam. They told me that they have now swapped in some Kelford cams (without the VCam) and can achieve around 130psi compression and the low end torque is better, but now the engine is doughy as.  It boosts and peaks at more than 1000rpm slower, with twin HKS GTIII RS, it doesn't get full boost until over 5000rpm. I have always thought the VCam was a bit disappointing at the low rpm. To a point I had to ride the clutch a fair bit to get up a small hill from stand still.  That was when I had a clutch.  Now changing to a 8HP, I don't have that luxury and this problem has become a major issue. I am beginning to think the VCam never work since the day it was installed.  Maybe it was just sitting at the most advanced point, that is why it went good at top end but very ordinary at the bottom.  Therefore, with the help of the Holinger 6 speed and paddle shift, as long as it was moving, it drove pretty good.
×
×
  • Create New...