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260z supplemental fuel pump necessary?


Big Jon

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Hey guys, I am rather new here, and although i didn't find my answer when I searched, I figured someone may have asked this question at one time or another. My question is, is it absolutely necessary to have the electric supplemental pump on the 260z, or is it more used for priming the line or keeping the line pressurized with high rpm performance. Mine is busted and clogged, and all I need to get the engine running is fuel delivery. My mechanical pumps works fine. Would it be horrible to run the car and take it easy driving only using the mechanical pump? Thanks much

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lol for ease I actually moved my filter to the engine bay ( I am not a small guy and dont like getting on the ground) and I plan on installing one more smaller filter before each of my carbs.

 

 

 

on another note if you want a stock pump at some point let me know...

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Hey dacshundt, I run 2 filters, one in the back and one right in front of the mechnical pump - I have a rusty gas tank :blink:

Here is an interesting tidbit I found:

Here’s what the 1974 260Z service manual, section EF Fuel System, page EF-7 says:

 

Electric Pump Operation

 

This system controls the operation of the electric fuel pump according to the engine speed. It receives the engine speed information from a voltage generated by the voltage regulator. When the engine is running below 400 rpm, the electric fuel pump cut relay #1 remains OFF and the pump will not be operated. While cranking the engine, the electric fuel pump relay #2 remains OFF and the pump will not be operated.

 

Under normal engine running conditions, both the electric pump and the mechanical pump are operated.

 

Have no idea why the engineers came up with this!

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"Have no idea why the engineers came up with this! "

 

Think about it...

 

Engine operation below 400 rpms with the key in the 'on' position, no electric pump operation.

 

Perhaps you've hit a tree, and broken a fuel line...

 

Do you REALLY want your electric pump dumping the contents of your fuel tank on the ground underneath you while you're unconcious and bleeding?

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Yeh Tony, I thought about that AFTER I posted.

Actually, I wondered what folks are doing that ADD an electric fuel pump to an early Z for that very reason(rollover/hitting something). However, it would also make sense to have the pump working when CRANKING the motor at start up time! OTH, the mechanical pump works just fine on cold starts - maybe not so good on a warm/hot start with heat build up under the hood. As you well know, the 260Z's wiring engineering and components leave a lot to be desired.

 

OTOOH, this pump WAS added for vapor lock/heat soak reasons - not to feed my webers after leaving the car at an airport for 10 days in the winter!

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I have always used an interrupt switch from Ford Products (Tempo-Topaz have them in the left rear corner of the trunk, Ranger Pickups under the mat on the passenger's floorboard).

I bolt them to the bulkhead where the wires go through the floor on a 280Z for the stock electric fuel pump. If you get hit hard, or roll over this switch will trip. You simply reset it with a push of the big red button on top.

 

Curiously, it's the same part Pegasus Racing sells for crash/rollover pump interrupt as well! Looks the same at least. But boosting it from the junkyard is cheaper and you can dissect the wiring harness on the trunk mounted location to get at least one meter of heavy gauged wire on all the connections...it's almost enough to go from fusebox tap to fuel pump.

 

Not that I'm cheap or anything! :D

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"Not that I'm cheap or anything!" - Man after me own heart! Information added to my ever growing personal Word Document! Many thanks for the tip.

 

I also have read that the 260Z fuel pump is also tied into the ECU on the kick panel, along with the nefarious set belt interlock system. I am considering cleaning up wires and units that are no longer need or wanted and this could be very helpful if I decide to keep the electric pump!

 

I did not know that the 260Z pump has a filter - I have to check that out - thanks for that tip!

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I got my 74 260z started without the pump(i had to reroute the fuel lines) but you can go to your local parts house and pick up an aftermarket pump for around $70 so why not replace it?

Hey guys, thanks much. Yeah, I currently dont have any money and I have the spare parts to get it running layin around the barn, but it wouldve sucked if i had to go out and get a replacement, even only at 70 bucks. But what i hear is good news! Pics coming soon...

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