240z (L28) Electric fuel pump install - what parts?

[Woody928]

Does anyone have some pictures of the fuel pump wiring which is apparently hidden close to the fuse box? I found the cables at the fuel tank, but not in the cabin so far.

Just catching up here as I don't seem to visit the forum quite as much these days but if you still haven't found this yet, then I have

If you locate the wrap/bundle of wires which are next to the centre console/under the dash on the passenger side hidden not so subtly by being wrapped in vinyl then the wires you are looking for are hidden in there. My dad located a two pin plug which was left disconnected from factory by following the cars wiring diagram. One cable is the power to the rear of the car and the other is a live off of the ignition. If you need then I can get you a photo.

We've totally overhauled our fuel system now and almost finished our install of the Facet Posi Flow pump which is fully wired up an operating with fuses, relay and hidden flick switch to disable or arm the fuel pump (a small security feature). I just need a new fuel filter to arrive which screws directly into my fuel pump and we're basically done. Then onto testing and setting the fuel pressure. I should be doing a full update on my project thread shortly.

 

[240L31]

Well, that escalated quickly. I spent way more time on this than I had planned but I am more than happy with the outcome. My goal was a super tidy (reliable solution).

Fuel pump bracket, ready to be installed

Bracket for the fuel pump controller

Mounts to the steel bar below the fuse box panel:

As I couldn't close the fuse box lid anymore, I had to find a solution. What I did: I 3d printed a 15mm lower mount for the "fasten seatbelts" display so it just clears the fuel pump controller.

New wiring harness

As you can see I did wire the rear defroster switch. I don't want to use the keywords here but you can imagine a new "secret" function.

I realized this morning that the fuel pump controller needs a signal from the negative side of the coil, whereas the 240z tach is connected to the positive side. I didn't want to run a new wire all the way so I got creative I tracked down the (unused) fog light wires which happen to have a connector right behind the fuse box!
So I crimped 3 new spade terminals (switched power, fuel pump output, coil negative side) and put them in a stock style 4-terminal connector.

Final result, doesn't get any tidier (new connector on the left side, purple wires)

Bonus, hard to picture but awesome: The choke light is connected to the fuel pump outlet and lights up once the pump is running. It then says "ポンプ" which means pump according to google translate I did a vinyl plot and put it to the backside of the display.

 

[Paul_S]

I love that!

 

[240L31]

I just did a quick test, the negative ignition coil signal via the fog light wires to the fuel pump controller works flawlessly!
Now the last task is to bolt in the fuel pump, should be a quick job for the weekend.

 

[240L31]

What's your opinion on post pump fuel filters? I installed a "regular" plastic paper filter after the pump, I didn't consider if it is rated at this pressure (4-5psi). I can't find any datasheets.

It seems to work fine but better be safe than sorry.

 

[uk66fastback]

Oooooo, another possible kit on the horizon?

 

[240L31]

Oooooo, another possible kit on the horizon?

No, that's an one-off kit

 

[240L31]

Final update: it all works. Fuel pressure right before the fuel rail at 3psi, rock stable:

The pump is very quiet.

 

[peter_s]

Is it stable when at WOT as well?

I had some issues with that, didn't notice it until giving flooring it up in the rev range with load.

 

[240L31]

I didn't drive hard yet. But I would be surprised, this pump delivers 50l/h at 3 psi. So when the needle valves are fully open, pressure inside the rail would drop and pump flow would increase up to 125 l/h at 0 psi. No way my stroker consumes that much fuel..

Which pump did you run?

 

[peter_s]

It's not always the pump that's the problem, it's the flow through the filter.

I have a very fine Earls metal filter due to my injectors. I never had a problem before, but now my Earls filter clogged up. I put another filter right after the tank which cleared my problem.

I know this isn't exactly your setup, what I'm trying to say is, just keep an eye on it. You don't want to have the car run lean without any protection. I have additional security with my WBO and ECU. But you'll know when you start pushing the engine, it's just a heads up if you feel it's struggling at the higher revs.

I use a Walboro pump. Sorry can't remember the flow rate.

 

[peter_s]

And I have to add, your installation turned out great! Well done!

 

[240L31]

Thanks for the heads-up, I also have a wideband monitor installed, so I will keep an eye on this. The fuel filter is the same as before (with the stock pump), so I don't expect any issues there. The pre pump filter is very coarse at 150 microns and won't be restricting.

 

[240L31]

@peter_s you were right. I just did several consecutive 120 Km/h-230 Km/h runs. After the second run, the carbs run out of fuel from 5000 rpm on! This means, that the electric fuel pump can't keep up with my 210 Hp engine. That's a terrible disappointment and I am going to convert it back to the stock pump. I can't believe this honestly.

If anyone is interested in my full setup (fuel pump block-off plate, fuel pump, bracket, fuel pump controller, 3D printed bracket + all wiring for the 240z), send me a PM. I am more than certain that there won't be any problem with a stock L24 or even L28. I spent lots of time on this conversion, the parts are top notch.

 

[peter_s]

Are you sure it is the pump? Not the filter?

 

[240L31]

Pretty much, yes. As the same filter with the stock pump works fine..

 

[peter_s]

That's too bad.

But why not get a better pump and keep your nice new setup?

 

[Rob Gaskin]

As Peter says it does seem a little strange that the pump can't supply enough fuel. Your mpg must be very high at WOT. Can you up the pressure? I know that may seem a funny way to address this issue but it worked for me recently I went from 2.5 to 3 psi.

Do you still have the return pipe in your system? If so try it blocked off.

 

[peter_s]

As Peter says it does seem a little strange that the pump can't supply enough fuel. Your mpg must be very high at WOT. Can you up the pressure? I know that may seem a funny way to address this issue but it worked for me recently I went from 2.5 to 3 psi.

Yeah, sounds like a pump issue, but there might be some other thing going on..

What's the spec of the pump?
Do you have stable wiring to the pump (made sure the signal is clean and strong at the pump?)

 

[240L31]

That's too bad.

But why not get a better pump and keep your nice new setup?

Maybe I am just to annoyed right now. Everything is made nicely for his exact pump. Besides that I've chosen this particular pump due to the minimal noise (I've found nothing similar).

As Peter says it does seem a little strange that the pump can't supply enough fuel. Your mpg must be very high at WOT. Can you up the pressure? I know that may seem a funny way to address this issue but it worked for me recently I went from 2.5 to 3 psi.

Do you still have the return pipe in your system? If so try it blocked off.

The pressure is set at 3 PSI and can't be changed (no regulator). I like the stock return style fuel rail, I think it is superior to non-return setups. Changing this would reduce reliabilty (i.e. vapor lock). Exactly the opposite what I am looking for

Yeah, sounds like a pump issue, but there might be some other thing going on..

What's the spec of the pump?
Do you have stable wiring to the pump (made sure the signal is clean and strong at the pump?)

The wiring is ok, I crimped new connectors all the way. The pump specs are: 50 l/h @ 3 psi and 110 l/h @ 1 psi. The SUs should work well with only 1 PSI so I guessed 110 l/h would be fine to never drop below 1 PSI.

I just did a calculation of needed flow according to Summit Racing: 210 HP x 0.5 (BSFC) = 105 lbs/hr = 17,5 gph = 65l/h

The second point is, that I realized my fuel tank was below 1/4 yesterday. It could be that the pump sucked air..


What really baffles me is how capable the stock mechanical pump seems to be!