I have upgraded my fuel system with a KGParts 1680cc second rail and additionally I have installed a Bosch 044 fuel pump and rewired the fuel pump to the battery (OEm fuel pupmp relais now steers an additional relais instead of powering the fuel pump)

See for info

https://www.rx7club.com/showthread.ph...+pump+rewiring

Now, when I put the key in "ON", the pump briefly runs and stops (not starting). This is normal as it wants to fill the lines before starting.

NOw, my KGParts rail came with a FPR. When the pump briefly runs, it shows pressure on the FPR gauge and drops to zero when the pumps stops. From my point of view it seerves no use in that way.

Wouldn't it make more sense if the fuel system would contain a one way valve (between pump and prim fuel rail) to hold pressure on the fuel rails? Even when the engine is not running?

 

If the pressure is fine way the engine is running and raises pressure ok, then you're all set. I have a high flow one way check valve if your interested. I bought it from Australia from Speedflow and only used it for 1000km until I changed out my Bosch and put in a Walbro. The valve is made to specifically screw into the Bosch 044 and the output is an-6

 

Well, the first thing I'd do is forget the Bonez cat. Run straight pipe. That Bonez cat will make your turbos glow orange from heat, they are junk in my opinion.

Fuel pump wiring: I would run a 10ga. 2-wire (red & black) from the battery positive & negative to the back. Fuse protected at battery of corse. Install a heavy duty 12vdc relay in the hatch (dont want relays around gas fumes just in case), I put mine in the spare tire tool compartment. Use the power & grounds for your new relay (use the 10ga ground for your new pump & OEM ground wire too). Use the OEM pump power wire to activate the relay, and the relay to power your new pump, done w/wiring.

FPR should come after fuel rails (though I'm sure you know this). **** can OEM regulator & damper. Guage on FPR will show 0 when car is not running, may stay pressured up for a bit, but will drop after car sits, that is perfectly fine. No need what so ever to keep rails under pressure when engine is not running, in fact I wouldnt recommend that at all myself. Also, I would forget about the check valve, that sounds like a potential disaster to me. A check valve failure could kill your pump, not to mention your engine. Just my opinion.

Good luck w/your fuel upgrade project.

Any pics???

 

The bosch 044 pump doesn't have an internal one way check valve like a walbro or stock pumps do. You can buy the bosch one but it isn't a high flow valve and also it's a banjo bolt and doesn't come with an-6 outlet. It can't kill your engine like like KD said, it's a one way check valve so gas doesn't return to the pump, a valve also helps the pump by not doing this!

http://www.furiousperformance.com.au...roducts_id=421
http://mazdarotaryclub.com/forums/sh...ad.php?t=59612

 

Don't worry about it. Pretty much everyones car is like that. The pressure doesn't hold after it primes. There's absolutely nothing wrong with that.

thewird

 

There's only two possibilities here. A: You have a problem and B: You don't have a problem.

Situation A: is you have a fuel leak somewhere (you would most likely see it or smell it)

Situation B is that your fuel pump does not have an internal check valve that allows it to bleed off the line pressure.

Most fuel pumps I've installed or worked with have a check valve and hold at least 20psi after priming. You're most likely fine, just check for leaks...

 

make sure the ignition wire to the relay does not shut off when cranking

 

to fuel pump relay*