L 28 swap coming soon.....couple questions

[5150 will]

I've gathered everything I need to make my carbed L 28 swap go smoothly. The only thing I'm a little confused about is the fuel pump. My car is a '71. I purchased the Carter in line pump per recommendations here. I did locate the green wire near my fuel tank so I can easily hook up the power for the pump. There is a brown wire there as well which I can't locate in any of the wiring diagrams as to what it's for. Anyone know what the brown wire is? Also, do I need to add a relay for this or would there already be one somewhere I'm not finding?

[conedodger]

That didn't work for mine. I tried tapping into the factory harness to get power to the fuel pump but it the green wire wasn't live. Now, it could be that it is only live for a few seconds when the key gets turned to start and when the engine is running, but I think that requires a couple of harness changes that mine doesn't have. The relays are not there. I just went to the coil for power.

[5150 will]

OK Rob. I haven't checked for the power there yet so that'll be next. The diagrams I looked at didn't show any relays either. Thanks for the heads up.

[madkaw]

Are you sure that's not a black wire? Also, on a 71 I will guess that the wiring is NOT complete behind the radio. There are numerous threads about fuel pump wiring on these early Z's.

I would have gone with the RX-7 pump, which is also highly recommended on this site-and very quiet compared to the Carter.

I would strongly recommend running a relay kit that you can order from jegs or Summitt.

I believe I touched on this wiring in my Triple Mikuni Thread

[Diseazd]

Why not just use the mechanical fuel pump.......It works just fine for all 3 of my modified L28's with SU's.

[5150 will]

Steve, no it's a green wire on the 71 and I did see it on one of the diagrams i looked at. Where it dead ends I also find a brown wire and was just curious if anyone knew what it was as I didn't see it on the diagram.

Diseazd, the head on the L28 doesn't have the provision for the mechanical pump as it's a P79.....now I could put my E31 on the L28......

[grannyknot]

5150 will, I took apart my wiring harness from a 1970 Z just a few days ago and the unused fuel pump wire that you found back by the tank terminates up behind the dash in an unused T connector. In that same connector is a black/white stripe wire that goes directly to the ignition switch. To find it follow the fuse box harness back about 16" to a clump of connectors. it will be in that area probably wrapped up with blue tape.

Chris

[Diseazd]

Steve, no it's a green wire on the 71 and I did see it on one of the diagrams i looked at. Where it dead ends I also find a brown wire and was just curious if anyone knew what it was as I didn't see it on the diagram.

Diseazd, the head on the L28 doesn't have the provision for the mechanical pump as it's a P79.....now I could put my E31 on the L28......

All 3 of my L28's are running P79 heads with mechanical fuel pumps. A machine shop can open up a hole for the mechanical fuel pump, or you can scribe it and do it yourself. The stud holes are already there.

[5150 will]

Chris, that'll be helpful for sure if I stay on this path. Diseazd, I'm liking that idea. Do you think i could open the mechanical pump hole up without removing the head? I don't have any problem running the mechanical pump at all and it would simplify things for sure

[Oiluj]

You might want to consider a dual system. I also have only the mechanical fuel pump. I added a electric pump with a switch on my previous Z as insurance, and am considering doing the same on my current 240Z. It's a belt & suspenders kind of thing...

[5150 will]

After looking at the mechanical pump on the P79 it looks to be no problem at all to open that port. Add the eccentric and I'm good to go. I'm gonna K.I.S.S. I'll just make sure I've got the area sealed off well for any debris and open it up. Thanks for all the help and suggestions guys!

[Diseazd]

When you buy the eccentric, make sure you buy the bolt and washer too. You don't want the bolt to bottom out in the cam. All are still available from Nissan.