Low fuel volume - Lateral-g Forums

DKz Garage · #1 07-14-2015, 05:56 AM

Here is a question for all of the fuel system experts.... I have an LS408 motor. LS3 top end, injectors, intake, 90 MM Fast TB. Car is up and running, went out with my tuner last night to get it dialed in. Under 3/4 throttle the car runs lean, my tuner dialed in a call for more full, but it did not work. Now my thought is this.... I have a Ricks Vaporworks tank with the 5th Gen Camaro Fuel pump set-up. Which should be more than adequate in terms of feeding the motor. The car runs fine under "normal driving, but goes lean when you get in it. The injectors show that that they are only at 38% duty cycle...so I know I'm not running out of injector. When I Installed the tank and ran the power wire to the dash relay, I ran a 14gauge wire. My thought was this, the pigtail supplied had 14 gauge wires...why not run that same (14 gauge) to the relay???? I believe this small wire running from the tank all the way under the dash is my problem...heck, the fuse size is only 10amps. In any case, I probably have a voltage drop due to the the length of the "small" wire feeding the power side of the pump, thus the lost of fuel volume under WOT. My plan is to install a relay in the trunk, run a 10gauge wire to the batt/relay and a 10gauge from the relay to the fuel pump power wire. OPEN TO ANY THOUGHTS....

**CarlC** · #2 07-14-2015, 10:51 AM

A fuel pressure gauge here is going to be your best friend. If a tuner performs work without having one he/she is leaving one of the best available diagnostic tools in the tool chest.

If the fuel pressure falls when the car goes lean, the pump is too small (or not enough power getting to it.)

If the fuel pressure remains high but the injector duty cycle is over 100%, the injector is too small.

If the fuel pressure remains high and the injector duty cycle is low, then the power enrichment/fuel tables/etc. needs adjusting.

As far as the power wiring goes, if you are going to use a relay and shorten the circuit, a 12ga wire is more than sufficient. The wiring harness that is supplied by Rick's is not a VaporWorx part.

If you have one, can you post up a photo of the top of your tank?

Che70velle · #3 07-14-2015, 02:23 PM

Make sure tank venting was done properly?