I know the fuel flows backwards. Does anyone know which is the in; the hardline near the firewall or the nose?

And of course I've searched. Just never found a specific answer.

Thanks

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/jdm-s5-tii-fuel-flows-backwards-763768/ ??

i think you might want to re-word your question as it's kinda confusing.

 

Yes, that's my thread. But it is conceptual, not specific.

There are two hard lines coming from the injectors on the drivers side of the car. They are side by side. Standing on the drivers side of the car, one is to the right (nearer the firewall) and one is to the left (nearer the nose of the car. One is the fuel inlet, one is the return to the fuel tank. Which is which?

 

The feed is closer to the front of the car while the return is closer to the firewall the feed goes from their to the hose that is right in the middle of the fuel pump. and the return is ofset to the left i believe from the middle feed hose. Thats how it was for my 86 non turbo but I imagine it would be the same. and i would change the fuel filter while i was their like i didnt 0.o

 

Thanks, Duck. This is a JDM S5 Tii and in those engines the fuel flows in a reverse direction compared to a USDM S5 Tii.

So I'm hoping someone with a JDM S5 Tii can tell me which of the fuel hardlines is In, and which is Out.

 

I keep checking this thread to see if anyone has answered your question. I have mine hooked up but I don't know if its right. I won't find out for another week or two anyway if no one does though.

 

Fuel lines at the firewall...
If you still have the stock fuel filter installed, that's the feed line.
The other one is the return.
If the stock fuel filter is not there, then you need to do a quick test - turn the key on and see which side shoots fuel out. :P

Fuel rails...
Spot the FPR - fuel pressure regulator.
It's the thing with the vacuum fitting (or fittings) on it.
The PD - pulsation damper - will not have any vacuum fittings on it.
Okay, once you know where the FPR is...
Fuel flow needs to hit the FPR *last* before going back down the return line to the gas tank.
Connect the fuel hoses so the feed is furthest away from the FPR.
The fuel flow should go through both fuel rails first before hitting the FPR last.

If any of this is not connected correctly, the engine will not start / run.


-Ted

 

Thanks, Ted. I'd gotten that all from the diagram on the place you might have heard of called FC3SPro. Great resource. You might want to check it out sometime!

The thing is that in my excitement to get the engine in I put the long block together and installed it before tracing the hardlines and labeling them. And once you get all that crap installed the lines are nary impossible to see.

Would this work? If I install the fuel source line from the filter onto one of the hardlines, and then put a length of fuel hose from the other hardline to a jerrycan, if fuel flows thru into the jerrycan do I then know I'm good? My assumption here is that either the PD or the FPR has some sort of check valve in it and that's why the direction matters.

Thanks,

Jim

 

It is the same as the USDM. I removed the intake manifold from my JDM S5 motor to remove most of the emissions (highly recommend) and it is the same. Just look at you diagram nothing changes.

 

Hey Boost. Actually, it's pretty well documented on the site that the fuel flows in the opposite direction in a JDM Tii versus a USDM Tii. Same structures and organization but the flow is opposite.

With as many JDM Tii swaps as there are out there you'd think someone would know. But if they don't, I'll get out the mirrors and flashlights and see if I can't trace the lines as Ted suggested. Given that I'm going to be starting a freshly rebuilt engine in a swap, I want to make sure that I'm eliminating as many potential "it wont' start" root causes as possible up front.

Now, if I can get some oil pressure...

 

That will work.

The PD doesn't act as a check valve.
The FPR does.


-Ted

 

Thank you, sir!