Fuel pump set up for triple webers on 70 240z

[Pleadingbark]

Why do I have to run an electronic fuel pump and then run a regulator to get the same output as my old mechanical fuel pump. When I pull out the mechanical pump, do I just use the L28 EFI plug that sat where the stock mechanical fuel pump would be? Do I want to put the electronic one by the fuel tank or will it matter? Will the filter go after the pump or before it? Do i need to get a different one aside from the OE style?

[240260280z]

Put the low pressure fuel pump near the tank so that it primes by gravity and so that it pushes the fuel.

You can put a filter between the tank and pump to protect the pump and carbs.

The carbs have built-in filters that should catch bits if your pump starts shedding impeller metal/coatings.

A regulator near the carbs and feeding them ~3.5 to 4 psi (measured at the carb) is required.

Cap off and seal the head where the mechanical pump was removed.

Do not use a high pressure fuel injection pump unless you have a good fuel pressure regulator with a bypass outlet for feeding the return line.

An unused power lead in the harness runs from the fuse box area to the fuel sender area.

You can use a 78 280z oil pressure switch and a relay to control the pump operation safely.

[Marty Rogan]

You can use a 78 280z oil pressure switch and a relay to control the pump operation safely.

Blue,

Can you give more details on this? What is it exactly and how, where is it installed? Is this a fuel cut-off switch that kills the pump when oil pressure drops?

thanks,

Marty

[Mike W]

Marty,

Yes I believe that a fuel cut off is what Blue is referring to. I just completed an install of something similar, but rather than using oil pressure as a trigger, I installed an inertia switch which will disengage the electric pump on an impact. I believe that other forum members have done this as well.

If you need more details about the switch and wiring, just let me know. It was a pretty simple install and gives some peace of mind in the event of an accident.

Mike.

[240260280z]

http://www.classiczcars.com/forums/showthread.php?43162-What-is-best-way-to-add-an-electric-fuel-pump-to-early-240z&highlight=fuel+pump+oil+switch

[Marty Rogan]

Marty,

Yes I believe that a fuel cut off is what Blue is referring to. I just completed an install of something similar, but rather than using oil pressure as a trigger, I installed an inertia switch which will disengage the electric pump on an impact. I believe that other forum members have done this as well.

If you need more details about the switch and wiring, just let me know. It was a pretty simple install and gives some peace of mind in the event of an accident.

Mike.

Thanks for the reply Mike. Yes, I would like to get detail info on how to do this. Can you provide P/N's and wiring details?

Marty

[Mike W]

Marty,

The inertia switch that I used was from BWD / Intermotor. I purchased it from Advanced Auto. You can find more information about it here:

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Fuel-Pump-Cutoff-Switch-BWD-Intermotor_18970192-P_1399_R%7CGRPSESWAMS_____

It was a little expensive, but this is for safety so it made sense to me to spend the $$.

I also used a fuel pump relay from Painless Performance. I did not want to add additional circuits to my electric system so I wired the pump up on its own new circuit connected directly to the battery (through the relay). Painless makes really good products and I also used them for my electric fan relay when I changed over to an aluminum radiator setup and replaced the old mechanical fan with an electric one. You can find more info about this product here:

http://www.painlesswiring.com/webcatalog/largeview.php?SearchField=50102

As far as wiring is concerned, it was pretty straight forward. The most complicated part was trying to identify the original power feed wire to the pump, which in a late 260Z was a little tricky given how it was wired from the beginning. If you have an older Z that did not originally come with the electric pump, I think this is a little easier.

I mounted both the inertia switch as well as the pump relay inside my glove box on the right hand side. It was a convenient place to install them and in the event of a false trip on the inertia switch it would be very easy to reset from inside the car. It was also convenient from a wiring perspective as the original pump wires are very near the fuse box located on the passenger side of the car.

Hope that helps. if you need some additional guidance on finding the correct wires for the original pump, just let me know. I believe that I did a write up on this and will find the link for you.

Mike.

[Travel'n Man]

My inertia switch switch is located on the passenger side firewall next to the battery (bright red) - very straight forward wiring through the relay - only for the fuel pump. These switch's will surprise you on the expense of them but if you have a wreck and the car takes a large enough impact that switch will save your life - better than the fuel pump running and pumping fuel out with no control...........when I installed it I was afraid a large enough pot hole or bump in the road would set it off but it takes more than that. I have yet to have a false impact yet.

[Marty Rogan]

Thanks guys. This is real useful information. It helps to get the details. I agree that that the cost is secondary to being safe.

Marty

[Pleadingbark]

Blue: Thanks for your help, found the little green wire up under the passenger side of the dash where the body harness and dash harness connect. Plan on running a 40 amp relay to that with its own dedicated power line off the battery. Also plan on using the air con circuit as its 12v on trigger. Seems the easiest for time being until I tear it all apart this winter. Datsun was really thinking running wires back there for a fuel pump that didnt exist at the time.