Jarvo2

240z Electric Fuel Pump Installation

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Almost finished my electric fuel pump. Had to bypass the oil pressure switch for the time being as I can't seem to get it threaded in.

I wanted to post this video as i purchased yeh same airtex pump, and I just wanted to know if this is normal. The pump doesn't make a continuous hum, but rather a dadada noise with the hum in the back ground.

Anyone else come across this? I have a filter between the tank and pump (pictured) as well as in the stock location.

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I should also note, the mechanical fuel pump is still installed, and in the video the car is not running.  Ignition on only.  You may have to turn the volume way up.  Is this cavitation?

Edited by HuD 91gt

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If the mechanical pump is not being actuated then I believe the pump is dead-headed. It will be noisy if it is dead-headed.

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Ok, i'll check again.  But I think it made the same noise when the car was running.  I guess an easy way to check would be to disconnect it prior to the mechanical pump into a bucket and see if it continues to make the noise.  I'll report back.

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On ‎05‎/‎14‎/‎2013 at 7:10 AM, Jarvo2 said:

The airtex pump I used only produces 4-6 PSI which is fine for the SU's. If you get a higher pressure pump then you'll need to put a regulator in somewhere between the fuel filter and the hard fuel line in the engine bay. I haven't had any issues with my low-PSI pump.

Two questions:

1. WHere exactly is the best place to measure the fuel pressure at the car? On the fuel line that goes to the rear carb or between the fuel filter before the gas gets through the fuel rail?

2. Which of this two pumps can dial approximately between 3.5 to 4 psi and less noisy:

Airtex 8012S

http://www.summitracing.com/int/parts/atx-e8012s/overview/

or

Mallory 4070LP

http://www.summitracing.com/int/parts/maa-4070lp/overview/

 

For the airtex 8012s, i guess i will need a fuel pressure regulator. Not sure yet! Please let me know!! Dont like adding more stuff to the engine bay ie a Holley fuel pressure regulator. I think this is not needed.

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1st time poster. Just finished dropping the tank for a cleanup and hose freshen and noticed the extra pair of wires with the fuel level sending unit on my early 71. Back in the day I had a 73 Z and it did have vapor lock problems. The dealer installed an electric pump that you could hear start as soon as the ignition was turned on. I'd always let it pressurize a little before starting and it seemed to make it a little easier to start when cold. I'm thinking of just getting the electric pump, hooking it up as the Datsun dealer did so it runs when the ignition is on. Is there really any big problem with this approach? My 73 ran this way from 74 up until the car disintegrated from rust in the early 90's.

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No problem.  I run an electric pump on my '71 and have removed the mechanical pump.  Are you having startup problems with the stock pump configuration?

Dennis

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Thanks for the reply! No, no startup problems, but I would have occasional vapor lock problems in really hot weather. The car has been a garage queen for over 10 years now so I decided that since I'm going to keep it, I better get it running again. Initially I'm cleaning the fuel system front to back and doing new fuel rubber that's E85 rated so I won't have to mess with that again. Figure while I had the tank out I'd get the K&N fuel pump and go electric, never had a problem with the electric in the 73 so why not? Also getting the rebuilt SU's from MSA and putting the TBC 6 to 1 headers on. Along with that I'm going with the Champion 3 row radiator and the double electric fans on the shroud with Evans waterless cooling fluid so I'm hoping the vapor locking and heat up in traffic will be no more than a bad memory. The car has original dealer installed A/C so I'm also going to get rid of the York and go with a Sanden compressor and update the rest for R134a. The wife and I are old so we got to have A/C!

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You may find that with the mechanical fuel pump removed that if the car sits for an extended period it may not start or crank excessively long. The electric fuel pump (whether new or old) runs off the safety relay under the dash. This relay is powered by the alternator. When cranking the alternator may not put out enough voltage to energize the relay. I found the relay needs 4.5 volts to energize and the alternator only puts out 3.5 volts while cranking. With no fuel in the carbs due to evaporation you will sit. The safety relay was designed by Datsun to kill the fuel pump in the event of an accident to prevent gas fuled fires.  No engine running; no voltage; no gas. The mechanical fuel pump would provide fuel to the carbs while cranking. My 1973 240 is used sparingly and the Webers go dry. I installed a byass switch ( montentary action) across the relay coil. Basically I hold the button in for several seconds to "prime" the carbs. Starts every time now.

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If I put it on the accessory position and I use that position to do things like listen to the radio with the car not running I wouldn't want the fuel pump running while the car is not. If the fuel pump is in the engine running position I can turn the key to that position and let the pump charge the fuel line for a few seconds and then start it.

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They way that @w3wilkes has described the hook up is the exact way my pump is wired.  It makes no sense to wire it to accessories as the pump would run when the engine was off and you would not want this situation.  In addition you would not want it wired to just the start position as the pump would turn off after the car was started.  You need the pump wired to the "on" position on the switch.  This way you can go to "on" before starting the car so that the pump will run and prime the carbs (a necessary requirement with triple Webers as the bowls tend to evaporate when the car is not driven frequently).  Once the car is started and the key is in the run position, the pump will continue to run while the engine runs.

However, you should also install an inertia switch in the circuit as well so that in the event of an accident the inertia switch will trip and shut off power to the pump.  You would not want the pump to continue to run after an accident especially if the engine shuts down as a result of the collision.

Mike.

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7 hours ago, Mike W said:

They way that @w3wilkes has described the hook up is the exact way my pump is wired.  It makes no sense to wire it to accessories as the pump would run when the engine was off and you would not want this situation.  In addition you would not want it wired to just the start position as the pump would turn off after the car was started.  You need the pump wired to the "on" position on the switch.  This way you can go to "on" before starting the car so that the pump will run and prime the carbs (a necessary requirement with triple Webers as the bowls tend to evaporate when the car is not driven frequently).  Once the car is started and the key is in the run position, the pump will continue to run while the engine runs.

However, you should also install an inertia switch in the circuit as well so that in the event of an accident the inertia switch will trip and shut off power to the pump.  You would not want the pump to continue to run after an accident especially if the engine shuts down as a result of the collision.

Mike.

 Mine is wired the way Mike describes it. That way I can prime the Mikuni's before starting engine. I picked up an inertia cut out switch that I have to install yet.

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Does anyone know how they wired these with a fuel pump in the factory? Empty harness, what did it hook up to? 

Then, in theory, if you connect the black wire to a manual switch to the green wire, that would power the green wire with ignition switched on? But in OPs setup, he used black wire to oil pressure switch to relay then to green wire?

When I got my Z, I flew out to get it and had to drive back. Half way home, fuel and fire both went out on me. Stuck overnight, the next morning in a small Idaho town, they put in one of these electric pumps powered by running a wire from fuse box to pump, slapped it right in line before the mechanical (still connected) and put in new points (dist). It ran better than when I picked up the car, but just a patch job to get me home. I've had issues with fuel ever since I got back and removed it and replaced the mechanical, so I'm going to install a new electric pump (the other one sat and won't spin).

Edited by thumper300zx

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11 hours ago, thumper300zx said:

Does anyone know how they wired these with a fuel pump in the factory? Empty harness, what did it hook up to? 

70-72 they did not have pumps.  73 and 74 had the pumps.  Not sure if the 70's had the wires, but 71 and 72 do as part of the harness. Maybe the JDM had FP in those years like the fog lights and it was easier to just include them and not use instead of having separate harnesses for each market.

My 71 was wired just like the original post.  Black and green wire to the tank and just hanging unplugged behind the heater console.

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Here's what I know. Bought a '73 brand new in July '73. It had mechanical pump only, no electric pump. Later that summer I took it in complaining of vapor locking. The dealer wrapped the fuel rails around the valve cover with a reflective metalized wrap. Took it back later, still vapor locking, but not as bad. The dealer installed an electric pump back at the tank. To be honest, the vapor locking was never completely cured in heavy summer traffic for the 20+ years I drove the car.

I now have a early '71, manufactured December '70, I'm the 2nd owner. I believe it's a series 1 car based on things like body vents on hatch, position of ash tray, rear window defroster line direction, etc.. It has the green / black wires for a fuel pump hanging down back at the tank. Haven't hunted yet but I presume the other end to be in front of the fuse box in the front left of the console area. I plan on converting to electric fuel pump in the next month, so I'll be digging into the console to find the wires to jumper with an inertia switch to activate the wires back at the tank. Under the fuel gauge sending unit on the tank are a couple of pre-drilled tabs that I'm guessing are for mounting an electric fuel pump. Based on my car I'm betting that the Z's were plumbed from the git-go for electric fuel pumps.

Side note: Found a blue taped wire w/bullet connector coming out of the harness right under the battery that is hot when the ignition switch is in the engine running position. How did Datsun know I needed that right there for my electric fan controller? :rolleyes:

Edited by w3wilkes

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2 hours ago, w3wilkes said:

Here's what I know. Bought a '73 brand new in July '73. It had mechanical pump only, no electric pump. Later that summer I took it in complaining of vapor locking. The dealer wrapped the fuel rails around the valve cover with a reflective metalized wrap. Took it back later, still vapor locking, but not as bad. The dealer installed an electric pump back at the tank. To be honest, the vapor locking was never completely cured in heavy summer traffic for the 20+ years I drove the car.

I now have a early '71, manufactured December '70, I'm the 2nd owner. I believe it's a series 1 car based on things like body vents on hatch, position of ash tray, rear window defroster line direction, etc.. It has the green / black wires for a fuel pump hanging down back at the tank. Haven't hunted yet but I presume the other end to in front of the fuse box in the front left of the console area. I plan on converting to electric fuel pump in the next month, so I'll be digging into the console to find the wires to jumper with an inertia switch to activate the wires back at the tank. Under the fuel gauge sending unit on the tank are a couple of pre-drilled tabs that I'm guessing are for mounting an electric fuel pump. Based on my car I'm betting that the Z's were plumbed from the git-go for electric fuel pumps.

Side note: Found a blue taped wire w/bullet connector coming out of the harness right under the battery that is hot when the ignition switch is in the engine running position. How did Datsun know I needed that right there for my electric fan controller? :rolleyes:

So you plan on going from live (on ignition) black into inertia switch then to green wire? What is the black wire even for at the back? These little aftermarket pumps can be grounded to the frame, so if black is coming from powered source to then go to green, why a black wire at back?

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Photos of harnesses, exactly where expected. So, here's my question... The green from console to tank in continuous wire. Black shouldn't be, right? But also, if not, why is the black there? To ground somewhere?

IMG_20170802_210840-747x1328.jpg

IMG_20170802_210859-1328x747.jpg

IMG_20170802_211339-1328x747.jpg

IMG_20170802_211622-747x1328.jpg

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Ok, tested. Black gets voltage with ignition in ON position. Green from console is direct (zero resistance) to tank green (last photo).

Seems like inertia switch between black and green at harness would work great.

Still not sure what black is at back, though. 

IMG_20170803_182527-747x1328.jpg

IMG_20170803_182519-747x1328.jpg

IMG_20170803_182900-747x1328.jpg

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I think the black wire of the green / black pair at the tank is ground. I had my tank out to clean and line it and the way Datsun has the tank situated I think it's pretty much electrically isolated from the car frame/body ground. Not really any metal to metal between the gas tank and the rest of the car. So if the tabs I mentioned before on the tank are for an electric fuel pump to be mounted there it needs to have a ground wire for the pump. Same reason there's a ground wire for the fuel gauge sending unit in the tank.

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Yes black at the tank is ground. I verifed with continuity meter. Interesting note in the  airtex video was to include a ground for the fuel pump to the battery. 

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