Guest Anonymous Posted March 20, 2001 Share Posted March 20, 2001 My Z has a knock or pulse in the fuel rail that sounds like a loud tappet only sort of duller. . . . Im told that its the fuel pulsing and because Ive got steel lines from the back to the front and stainless braid from the steel lines to the fuel rail it sounds LOUD! anyone had this problem and know of a way around it? Ive got an Autometer fuel pressure gauge (with an isolator) and it seems to bring the sound into the cabin, to the point where Im thinking about removing the gauge. Thanks for any help Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted March 21, 2001 Share Posted March 21, 2001 Does your ignition fire off of your front pulley(direct crank fire setup)? Also, do you run an electric fan? If yes to all of the above, the fan may trigger the ignition setup causing the injectors to fire. That is about the only thing I can think that will cause your fuel system to pulse. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 21, 2001 Share Posted March 21, 2001 Yes Im running a direct fire system with 3 coils, but the pickup is from the flywheel. My Fans are also switched from the computer. The pulse sounds as though it happens every time each bank of injectors fire. . .Im not getting any false firing as far as I know. I have picked up a bosch fuel damper which is adjustable, and am hoping this will reduce or eliminate the noise. Fingers crossed. thanks & cheers Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted March 21, 2001 Share Posted March 21, 2001 I run all braided lines and have no noise as you describe. Does this happen when you kick on the pump and the car is not running, just for when you are pressurizing the system? My fans use to trigger my ignition as I described and it would fire all the injectors causing it to make a loud pulsing sound. Do you batch fire all of your injectors? You might try to alternate the injector firing and pair them up or run sequential to see if that helps. You would potentially pressurize the system and then your 6 big squirters suddenly open up relieving the pressure. Is the fuel pump run off of its own relay and not on the same power as the injectors? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 21, 2001 Share Posted March 21, 2001 The injectors fire in 2 banks of 3, The fuel pump is on its own relay & fuse indirectly operated by the computer (the computer earths the relay which switches the pump)Im running a big bosch pump, but at idle its only running 37psi. The noise is there all the time, at idle or under revs. .. bearing in mind that Ive not had the motor over 3000 rpm (just got it going and havent sorted the A/F ratios) My injection guy seems to think Ive got injector body to metal (fuel rail) contact somewhere, but I dont think so. . . . I also got onto Autometer and they said send the mechanical gauge in as Id never get rid of the pulse and they'd send me an electric one. . .which makes me wonder if its the gauge causing the noise. . .I'll pull the gauge off this afternoon and see if it makes a difference. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.