1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

13B Swap Fuel Q

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Old Jul 21, 2007 | 12:06 AM
  #1  
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Nekurd
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From: California
13B Swap Fuel Q

Well, I'm finishing up my fuel system on my car and I got somewhat confused how the lines should be routed. I was thinking it goes from
1 -> 3
4 -> 6
7 -> 2
And 5 connects to any air nipple on the intake manifold?
This is a quick diagram I made, please refer back to it when explaining this to me, it will help a lot. Thanks
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Old Jul 21, 2007 | 09:31 AM
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From: St Joe MO
Your profile shows that you have a 79, which doesn't have a separate charcoal canister, it's built into the air cleaner lid. If you're upgrading your's to the later style system with the fender mount canister, refer to Sec. 4A, p. 3 of the 85 FSM. Link to the online FSMS is in my sig line.
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Old Jul 21, 2007 | 11:11 AM
  #3  
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Nekurd
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The thing is, I'm putting a 13B from a 91 n/a, keeping it FI, into my 79. I looked at the GSL-SE manual too but it still looks different
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Old Jul 21, 2007 | 06:18 PM
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From: St Joe MO
Ah, you should have mentioned the engine swap in your 1st post. I don't have the 91 FSM on hand but you can find the routing diagram in the link in my sig line. Follow the routing diagram in that manual to the letter if you want to get it past the CARB ***** in CA. You might PM Steve84GS since he has a CARB approved S5 TII install in his 1st gen.
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Old Jul 22, 2007 | 02:05 AM
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If your trying to keep everything on the S5 engine like stock,then basically nothing you have listed in the first post is correct.With the stock EFI and smog gear working,I dont recommend anything but factory routing of the hoses.

The charcoal canister just needs two hookups.Depending on what car you got the canister from,it might which is which.One line is the inlet which draws fuel vapors from the gastank.The other is the outlet and leads to the engine crankcase where the fuel vapors mix with blowby and are drawn into the engine though the crankcase ventilation system.The hookup for the canister outlet is on the engine block,behind the oil filler pipe.The nipple on the bottom of the canister is just a vent/drain and doesnt hook to anything.

The fuel lines on the engine are the feed line from the pump to the injectors and the return line from the injectors back to the tank.The front line is the feed and the rear line is the return.

Youll have to determine which fuel line on the firewall is the feed and which is the return......since you have a 1st gen accepting a 2nd gen engine,it wont be JUST like stock.I hope you arent using the stock fuel hardlines to feed the engine.The stock 1st gen's small,carb specific return line is far too restrictive for the high volume/pressure that EFI requires.Youll need to run another 5/16" 1st gen fuel feed line,alongside the original 5/16" feed line,then use it as a return.Youll also want to install a high pressure EFI fuel filter somewhere on the feed line before the engine.Its not a bad idea to put the filter near the engine,so you can change the filter without getting under the car and for easy ID of which line is the feed and which is the return.

If this makes sense,then finishing up the fuel system should be easy.
If its all Greek to you.....sorry,I'm Greek......but I do know what Im doing!
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Old Jul 27, 2007 | 01:52 PM
  #6  
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Nekurd
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From: California
Originally Posted by steve84GS TII
If your trying to keep everything on the S5 engine like stock,then basically nothing you have listed in the first post is correct.With the stock EFI and smog gear working,I dont recommend anything but factory routing of the hoses.
Exactly what I want to do, nothing custom just everything stock

The charcoal canister just needs two hookups.Depending on what car you got the canister from,it might which is which.One line is the inlet which draws fuel vapors from the gastank.The other is the outlet and leads to the engine crankcase where the fuel vapors mix with blowby and are drawn into the engine though the crankcase ventilation system.The hookup for the canister outlet is on the engine block,behind the oil filler pipe.The nipple on the bottom of the canister is just a vent/drain and doesnt hook to anything.
My car has 4 hardlines attached to the firewall, 1 for the front brakes, 2 for the main/return hose for the fuel rails, and 1 I think is for the rear brakes(I'll have to check). So basically I don't know where the charcoal canister would connect to the inlet if there are no more hardlines to the gastank, unless the guess that the last hardline is for the rear brakes is incorrect. On the 85 EFI manual, the outlet connects to the nipple behind the oil filler neck, but the 91 n/a manual states that something already connects to that nipple and also the back of the dynamic chamber. Thus it says that there is another connecting nipple below that one, but I can only find 1...


The fuel lines on the engine are the feed line from the pump to the injectors and the return line from the injectors back to the tank.The front line is the feed and the rear line is the return.
I attached the 2 fuel hoses onto the block by the oil filler neck, main to the left and return to the right.

Youll have to determine which fuel line on the firewall is the feed and which is the return......since you have a 1st gen accepting a 2nd gen engine,it wont be JUST like stock.I hope you arent using the stock fuel hardlines to feed the engine.The stock 1st gen's small,carb specific return line is far too restrictive for the high volume/pressure that EFI requires.Youll need to run another 5/16" 1st gen fuel feed line,alongside the original 5/16" feed line,then use it as a return.Youll also want to install a high pressure EFI fuel filter somewhere on the feed line before the engine.Its not a bad idea to put the filter near the engine,so you can change the filter without getting under the car and for easy ID of which line is the feed and which is the return.
Will I really need another 5/16" hardline? I'm not going to be running an adapted 2nd gen internal fuel pump, but instead surgetank, universal external carter fuel pump, and a Bosch 910, 130 LPH (5 bar) In-line Fuel Pump. I was hoping the setup wouldn't require another hardline...


If this makes sense,then finishing up the fuel system should be easy.
If its all Greek to you.....sorry,I'm Greek......but I do know what Im doing!
If what I wrote made no sense then I'm sorry, I'm just trying to double check before doing anything final. Thanks
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Old Jul 27, 2007 | 11:12 PM
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From: Rohnert Park CA
Surge tank or intank,your supplying fuel to the rails via a high pressure EFI pump.If your gonna replicate stock conditions,Id recommend running a 5/16" return line like the EFI engines are used to.You dont want the tiny little return line to become a restriction that the fuel pressure regulator cant compensate for.Its easy to do,just pull another 5/16" feed line off a junkyard 1st gen,and install it alongside the original feed line.The small gaps from the hardline to the tank and engine can be jumped with EFI rubber hose.Heres a rough pic of mine,you can see the connecting lines on the left,leading to the top of the tank.......



If you have an SA,I cant say for sure about the location/size of the vapor recovery line from the tank,since the 79-80's have the special charcoal canister inside the aircleaner rather than a standard canister.Regardless,it must have SOME sort of hardline from the top of the fuel tank to the enginebay.RX-7's always have their plumbing on the drivers side,as to avoid the hot exhaust system on the pass. side,so thats a place to start looking.It should be a small line,since it only has to route low pressure fuel vapor.
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Old Aug 22, 2007 | 01:24 PM
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Nekurd
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Sweet. got everything together. only thing now is my bosch "out" nipple is threaded and has holes where the fuel comes out. I was going to put a hose over it and clamp it but that would block the holes. Has anyone else used a 910 Bosch pump and what did you use as an adapter for the "out"? This is all that I have left
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Old Aug 23, 2007 | 09:40 AM
  #9  
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Nekurd
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From: California
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Old Aug 23, 2007 | 04:40 PM
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Hunting Skylines
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Just remove the stock fitting and run a brass fitting with a 5/16 hose tail.
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