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MX5 Build - Fuel system help required
Jonb_5 - 13/7/18 at 06:36 PM

Evening All,

Apologies if any of this is stupid questions but I cannot find anything that I would class as an idiots guide to assisting with my questions.


I am basing my build on a 2003 MX5 and keeping as many components as possible to keep costs to a minimum. I have now found a fuel tank which will accept the standard MX5 fuel pump / sender etc and need to get the hoses connected up.


The tank sender unit which sits in the tank has 2 outlets - feed and return (can anyone advise which is which?) The return, I am assuming will come direct from the engine bay and the feed via the filter to the engine bay.


Now, I have been advised to ditch the carbon catch canister from the system so can anyone plead advise where I should now be connecting the feed and return lines in the engine bay? Would I connect the feed direct to the fuel rail now? Also, where would the return go, it doesn't appear there is a take off on the opposite end of the fuel rail for this?

I also have a regulator which I assume I need to connect inline somewhere so would the return come from this regulator back to the tank.

I also have a separate take off on the tank which I will just vent to the atmosphere through a roll over valve.


Any help would be appreciated as once this is plumbed in I can attempt starting the car for the first time.


The last question is what type of fuel line to use. Should I use a mix of copper and rubber or is I acceptable to run rubber right the way through the car?


Many Thanks

Jon


gremlin1234 - 13/7/18 at 07:06 PM

ensure any/all rubber (or other flexy) hose is marked as suitable for fuel


chris_smith - 13/7/18 at 07:44 PM

Search charcoal canister removal on the mx5nutz forum, there is a guide in there. I’ve installed same setup, I used fuel hoses to 8mm copper down the tunnel then original fuel hoses to engine


tims31 - 13/7/18 at 07:56 PM

I used kunifer pipe down the tunnel of mine as it copes better with the transportation of fuel over that of copper pipework. If access down the tunnel area is difficult it is better to run solid lines like the kunifer as over time you will possibly need to replace the rubber pipe as it perishes.


miskit - 13/7/18 at 08:45 PM

I have plumbed the same year engine 1.8 VVT into my Sandrail,
The in tank pump pushes out to the filter assembly (the sealed metal unit) the return line is back from that to a pressure regulator (the small cylinder in the pic) in the tank - you can identify the in/out from the pic.

Then there is a single line to the fuel rail, via the pulsation damper which the small rubber mounted cylinder close to the engine. I can take pics if you need them.

This is after I modified the tank pick up to fit my shallow tank and removed the indicator to use in a different part of the tank but you get the idea.





So basically out --> Filter ---> Pulsation damper ----> rail

Filter--->Tank Press reg.


miskit - 13/7/18 at 08:50 PM

Just found the photo note I made for myself when I took it apart!



I just re-used all the Mazda bits. Pretty sure you cant use rubber pipe as the tank pump runs at 60psi!

[Edited on 13/7/18 by miskit]


PorkChop - 13/7/18 at 11:00 PM

quote:
Originally posted by chris_smith
Search charcoal canister removal on the mx5nutz forum, there is a guide in there. I’ve installed same setup, I used fuel hoses to 8mm copper down the tunnel then original fuel hoses to engine


There's not any more - Nutz had a major meltdown a couple of weeks ago, taking almost all of the content with it. They are still waiting for a fix...


Jonb_5 - 14/7/18 at 06:57 AM

Perfect, thank you for the replies, clears it up alot and removes a few bits I thought I'd have to try and fit in somewhere.

With regards to the fuel line I've read you can get the rubber to take 80 or 120 psi?? If I were to flare the ends of the copper lines and use the house clips do you think this would be acceptable??

Thanks

Jon


ianhurley20 - 15/7/18 at 08:05 PM

Yes it is. I soldered olives onto the ends of my 8mm fuel pipes and they worked fine for IVA and now two years later. A flare will do the same