RXDI fuel pressure or fuel regulator

[Brprxt215]

So I posted a week or two ago about fluctuating rpm and only 40mph at 6800rpm. Since then I have put in OEM rectifier, new wear ring and pulled the fuel neck off drained old fuel and put fresh in(unsure state of original fuel). Took to dealer and had BUDS hooked up. Only code was multiple 12v low which I’m assuming is from old aftermarket rectifier. Went to water test and could not even get it to run 40mph or 6800rpm before it stalled out. Would start right back up every time and run at idle as long as I wanted. I built a fuel pressure gauge yesterday and tested.(

)(

) videos of test while under load at boat ramp . One thing to note is after shutting off it leaks pressure and drops to about 20psi after about 10 mins. I was reading it should sustain pressure for a long while. Does this sound more like fuel pump or fuel regulator problem? Anywhere else the pressure could escape from?

 

[mikidymac]

Fuel pressure issues will not cause a trouble code.

 

[Brprxt215]

Fuel pressure issues will not cause a trouble code.

Right but the maintenance light came on while water testing so I wanted that reset. Also didn’t know if maybe one of the TPS was bad or something.

 

[DanSquires]

so yes, you're losing pressure. Did you replace the in tank filters?

 

[Brprxt215]

so yes, you're losing pressure. Did you replace the in tank filters?

I did not. I was thinking about pulling the fuel baffle to check the socks and pump. I will do that in the next couple of days

 

[etemplet]

What did you do for the fuel pressure hook up. T with a schrader valve up front by the external fuel filter? I want to rig something up but I need to do some reading first. I just replaced the filters on a RX DI I have.

 

[Brprxt215]

What did you do for the fuel pressure hook up. T with a schrader valve up front by the external fuel filter? I want to rig something up but I need to do some reading first. I just replaced the filters on a RX DI I have.

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Here is a pic of my setup. I wish I put a Schrader valve in it with a bleed off line to relieve the pressure afterwards. How hard is it to pull the fuel baffle? Did you have to cut the fuel line off the tank going to the filter?

 

[etemplet]

PIA for me is getting the console cover off. Once you pull the cover you can get in there pretty easy. I pulled the baffle with the filter and lines still attached. Just be careful and keep an eye on the fuel level arm. It you look in the picture you can see the hoses are still attached. to the baffle. Don't drop those little nuts they like to roll off and under the fuel tank. I use a small air ratchet... that part goes pretty good. The tank top gasket only fits one way I believe so get that right. Clean the fuel level indicator contacts and make sure it is reading properly.

Rivets are 1/8". I've seen people use screws getting those back on. Be gentle and pay attention to the little check valve with the washer on the bottom. Check it out good before you take it apart. The pump always moves around and I end up aligning the top portion. It should move smoothly. The chamber compresses when you put it in the tank. It is on a spring. Hope this helps. Good Luck

 

[etemplet]

On the fuel pressure, I have a gauge rig that has a depressurizing button and a discharge line. Works very cool when I Have a line with a schrader valve.