Need advise please
PWM set to 100 and still 53 psi
At 2000rpm it has a drop to 50 psi
Is it 53 when not running, just key on prime?
No, on prime it's 43
I'm thinking of swapping the lines around to see what effect that has.
To make sure. You are running the "Orange" wire directly to the fuel pump. No relay.
Next, I would try blocking return line and check prime pressure. If it goes way up, then we have a regulator problem. No big deal, fairly easy to change. I can get you the part number. It is an off the shelf part.
If no change with fuel pressure, remove your filters. No change, then I would look at the pump.
Quote from Austin DeHaas on August 15, 2018, 9:50 amCongratulations 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.
What's interesting in my case, is that after a few weeks of operation, I just happened to notice when the car was running funny, that the fuel inlet pressure had changed to 100 psi when it was at 43. Something physically changed in the internal regulator at some time to prevent fuel from being returned. It's I guess possible that some debris got in there and shut it down somehow.
Austin,
Yes orange wire is direct and no relay, blocked the return and pressure went over the 100psi mark so I guess it's the regulator.
If you could let me know the part number I'd appreciate it.
FYI, I have a vacuum hose connected to the regulator.
Thanks
It's kind of curious that your psi seemed to be regulated at 43, just like my meanstreet 800 is by design with the lower internal pressure regulator. 43 is what I was getting on prime also. I wonder if they mistakenly put in the meanstreet 800 regulator in your 1200? Anyway a regulator swap sounds like it may fix it for you.
Who knows, it does seem strange though that both are 43psi. I just want to get it running right so I can start to understand it better for later when I move over to centrifugal supercharger.
Fitech will probably send you a new one for free.
Emailed Fitech and this is their reply......Hi