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72 240z fuel pump question


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I have a 72 240z that was made in September(9/72) and it had an electric fuel pump on it that is powered by a splice in the engine bay and ran down the tranny tunnel to the pump. my question is did my 240z come from the factory with an electric fuel pump? there is a black and green wire that are wrapped together with the two wires that connect to the gas tank to tell you the fuel level and i was wondering if they were for a fuel pump or something else(they aren't hooked up to anything). i remember reading somewhere when they switched from mechanical pumps to electric but i cant find again. thanks in advance for the help.

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Get a manual so you can sort it out, but yes there are wires in the back for the stock electric fuel pump (I think mine are b/g). The e-pump was a dealer installed option used to help solve the notorious "vapor lock" the early SU cars had.

 

You will also need a harness or make one of your own for the under the dash connection. The one under the dash has an in-line fuse.

 

This is how my 71 is and I am making the assumption it is the same for your 72, but that may not be the case.

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Mine had a electric pump and mechanical. I took the mechanical one out and just used the electric one. Then it crapped out on me and i got a second hand one which is crapping out to. I'm in need of a 3-5psi fuel pump. Oh and those green and black wire are to measure how much fuel is in the tank i had bent the little clips inside the thing that goes over it and i replaced those today so i can see how much gas i have in the tank. Guess what I'm on E lol. As for the fuel pump it self there should be a wire on the top and one coming out the side i believe and those 2 are the ones that power the pump. Hope that helps any.

 

-Carfan

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To my limited knowledge (I have owned the car off and on for 30 some years), the early cars did not have an electric pump from the factory in the US (it is pre-wired for it, so they may have been stock on JDM cars). You could buy one from the Datsun dealer that bolted in and looks stock. It was a pretty simple plug and play (I know, I did it). You should get some type of a cut-off switch (Datsun offered it as an option) so if you are in a wreck and a line breaks, the pump stops.

 

Some guys added the electric one in addition to the stock mechanical one. Some guys took out the mechanical one, which required a block off plate. As I said, it was done to deal with "vapor lock" back when the cars were new. This is the same reason you see the fuel rails wrapped in insulation of various kinds.

 

According to this: http://www.autozone.com/az/cds/en_us/0900823d/80/1d/1d/80/0900823d801d1d80/repairInfoPages.htm

 

It should be a green off the pump and black/white off the car. I think the Nissan pump is self grounding, but I am not sure. Hope that helps.

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Picture of the old or new pump would be great, I would like to see the bracket. I am restoring one at the moment and would like it to look as the 72 dealer optioned!! I know I am on Hybridz and stock don't cut it...but this car isn't mine. Lol

 

Thanks

Dayz

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Im not sure how the pic will turn out since its dark but i'll go and snap a few of it. Soon as i find my phone which i just had. Found my phone. I had a real brain fart i will give +10rep to guess where my phone was lol.

 

th_01-28-08_2024.jpgth_01-28-08_2023.jpgth_01-28-08_2022.jpgth_01-28-08_2021.jpg

 

 

They holley pumps just fine but it cuts on and off when it wants to. I just noticed that crush im going to look at it now.

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Electric Fuel Pump In Picture Appears To Be Bendix.....currently Manufactured By Purolater As "facet" Pumps. Have Used Both The Lower Pressure And 7 Lb Pumps(with Holley Fpr) In My Z To Feed Su Carbs. Have Also Used Holley Pumps....and Others As Well, And The Facet Units Are Tops In My Experience. John T.

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I have a 73 240 and an early 260. Both have the said 2 pumps. I read the factory manual. the electric pump doesn't start working untill you hit a certain rpm during cranking or running. ( I have to recheck the rpm spec)

If the car sits for a long time, the check valve in the electic pump can stick causing no fuel delivery. You don't want to know how long it took me to get my fuel system straightened out........car sat 15 yrs in a garage!

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