Need advise please
Watch your AFR Learn. A little less learn with cam 4. This means the ecu is working less to meet targets. More efficient.
But, with fuel pressure issues, all this is a mute point.
What are you using for a gauge? Try blocking the return. There is a cap in your kit. See what the system deadheads at. The 90 shouldn't be an issue. This is a pressure problem. Not a flow issue. When you tuen the key on, pressure should go to 58 or more.
My aeromotive 340 pumps will deadhead over 100psi when deadheaded. That's at 100 pwm.
Yep, mine went way over 100 without the return.
The return pipe is 1 ft of -6 from the Fitech and then it goes onto -8 back to the tank, the -8 was my feed on the carb but as the Fitech is -6 I ran all new -6 and used the -8 for return as I had read a few quotes saying it would be ok.
Do I need to fit a regulator or replace all the -8 for -6 or smaller?
Seems like the internal pressure regulator in the Fitech isn't regulating to 58, but instead 53. I had the opposite problem with my meanstreet 800. I looked at my fuel pressure entering the unit and it was at 100 psi, coincidentally the same pressure my fuel pump is rated at, so the Fitech quit returning any fuel, even though the line was clear. I had to plug the return on the Fitech and put in an external fuel pressure regulator that I regulated at 58 psi. Now my gauge at the Fitech fuel inlet reads 58 psi, problem solved. You could do the same thing as I did and fix your fuel pressure problem I'm thinking.
Without making a long post, I'm just going to say I don't believe it is the regulator.
Austin, I wish you would elaborate a little, this is how we learn. So what are you thinking it is, if not the regulator? That was your concern that it was at 53 and not at 58 right? Or, do you think that's not enough to make that much difference in performance? I'm just glad I got mine regulated now where I want it. 😀
Austin,
Do I need to restrict the return pipe, is the -8 to much?
Would -4 be better, I would have thought it was to small but having seen the difference in pressure by blocking the return I'm thinking it would allow enough pressure to let the unit regulate and to me the lack of pressure also explains the bogging down on acceleration.
Thanks again
Bdhulderman
I see what your saying, but part of the attraction to the Fitech for me was how the unit self regulated which was one less item in the engine bay, if it is broke then an external regulator it would have to be but hopefully the regulator is ok although changing pipe work is going to be a pain if that's the answer.
Cheers
My return line back when I was using the internal regulator was -6AN and it's the same now with external regulator. It was kind of a blessing that the internal regulator quit releasing fuel to maintain pressure, because I thought it was too low anyway when it was working. On the meanstreet 800 it's regulated internally at 43 psi, that's why with the 8X64 lb injectors it's only rated at 800 Hp, instead of nearly 1000, so now with external regulator I can put it wherever I want, namely 58 psi like the other fitech units. Hope you get your problem fixed.
Congratulations Brandt. You made the 1000th post. Sorry, no prize.😂😂😂😂
FPRs do not typically regulate to little. They will either have no pressure or too much. Low pressure is usually do to a flow problem or pump issue.
I don't feel, in this case, that we have exhausted all the possibilities.
In the case of your Corvette, I don't believe it was the regulator either. You have a high flow pump to feed your massive small block. You are running it without PWM. Therefore your pump is running at 100%. Even with a 340 Aeromotive pump, I can exceed the capabilites of the Fitech regulator. The solution for you was to run an external regulator that could handle more capacity. Quite simply the Fitech needs the PWM capability to perform properly with its own regulator.
In this case, we have a 340 pump running PWM. The same configuration that I use. I want to see more investigation before we start buying parts.
Step 1: max out PWM and see if pressure rises.