no power to fuel pump and butchered harness

[bahelion89]

well guys...it started as a simple fuel tank flush, and now its a nightmare.

 

so the car turns over but the fuel pump is not getting any power.

 

first things first i yanked the pump and ran lines to the battery and the pump works just fine..some of the coating on the wiring was cracked off so i just snipped the lines and in the process of running new wire.

 

after that i will be checking power before and after the relay to see if the break down is there...meaning new relay? 

 

Second and kinda disturbing is the fact i found a group of wire/connections just dangling next to the trans...do the sensors in the trans connect to the starting system?

 

the more i dig the worse things get..

 

i also have a random toggle switch in the section of the harness where the radio is...any ideas what thats about?

 

any and all ideas appreciated 

 

 

sensor on top of trans

 

random toggle in radio harness

 

all the other funness hiding in my car

 

 

the relay that is missing here is sitting inside currently

 

they bypassed the key that was having issues and did this

[NewZed]

I'm going to guess 75-77 280Z with a 5 speed swap., based on the problems and pictures.

 

Six posts and the writing style suggest that you may not know how the 75-77 fuel pumps get power, possibly believing that the pump should be powered when the key is on.  That's not correct.

 

Just guessing.  How close am I?

[bahelion89]

Not sure about the swap..

 

I'm learning as much as possible through the fsm.

 

1975 280z

 

My knowledge is with early turbo dodges.

 

Please school me exactly how it gets power so I can get it on the road.

 

From what I understand..u turn the key to the on position and the pump cycles.power goes from the battery to the ecu and relay then to the pump....

[NewZed]

From what I understand..u turn the key to the on position and the pump cycles.power goes from the battery to the ecu and relay then to the pump....

if u. have read the fsm you would know that is not right.

 

Unfortunately, learning about your car via the internet is going to be difficult because you are from the new phone-based generation.  The diagrams and drawings are just very difficult to see and understand from the tiny phone screen, not to mention the difficulty in communicating via tiny word replacements like "u" for "you".  Plus, the general weakening of thought processes that seems to occur from thinking in text-speak.  Kidding, but serious.  You could look at one page and read another in the FSM on a full-size screen, and understand exactly how the fuel pump circuit operates.

 

The operation of the fuel pump is described and illustrated in the Engine Fuel chapter.  Key words and acronyms are AFM, EFI relay, fuel pump relay, and fuel pump contact points.  Good luck.

[Pharaohabq]

The Toggle around the radio is probably a manual switch someone put in the raise and lower the power antenna.  

 

The mess of wires over the tranny I believe are for the Auto transmission. I'm not certain about that, but they're not connected to anything, so just tape them up and forget about them UNLESS, you really feel like tracing wires with the FSM.  

 

The Fuel pump gets momentary power at startup, but needs the switch in the AFM to be open to keep running.  This is detailed in the FSM.  You should also read the EFI bible. Both will help you immensely. The links are on here if you search.

[bahelion89]

i have both the efi bible and fsm downloaded onto my laptop. both have a lot of knowledge and its hard to learn when you only get an hour here and there.

 

thanks for the input on the trans swap i was not informed one was ever done. its part of the mystery of this car...and frustration.

 

guess its back to the drawing board (aka Fsm) i will be going through it with a fine tooth comb. 

[NewZed]

Read EF-15 (not 14) and look at EF-7.  The pump never gets momentary power, that's a 280ZX feature, not 280Z.

 

The wires in the tunnel could also be left over from the vacuum advance solenoid power switch that the original 4 speed had.  Emissions chapter.  Check them for power with the key On to be sure you don't have a short circuit waiting to develop.

 

Note that there aren't many shortcuts or tricks to get the EFI working right.  The emissions system from the PCV to the charcoal canister need to be connected and working properly, with no vacuum leaks, for the ECU to meter fuel correctly.  All air must pass through the AFM.  Even the dipstick needs to be sealed.

Edited September 25, 2013 by NewZed

[bahelion89]

Well,

 

My car, when running had monetary power to the pump.

 

As soon as the key went to the on position, the pump started cycling. There was a quiet ticking noise, the tach danced, and flip the ignition toggle switch to start the car.

[NewZed]

Edit - I might have mis-read the "momentary power at startup".  Maybe Pharaohbq meant when Starting.  The "momentary" part got me since the power stays on if the engine starts and runs.

 

As for having power with the key On but engine not running, that's not factory.  There's probably some funky PO wiring you'll have to figure out.

 

EF-15 describes well what the factory designed it to do.  Good luck.

Edited September 26, 2013 by NewZed

[9rider]

There is 4 wire to the tranny, 2 for the reverse light switch and other 2 for the neutral safety switch. If you have have 4 speed MT then those 2 neutral switch will be use, the 5 MT don't have that. Good luck with other stuffs that have problem.

[DuoWing]

I skimmed through the topic, but I was just looking through my 76' wiring diagrams the other day and it goes very similar to 280ZX/Z31 wiring. Fusible link runs down to an EFI relay under the dash above ECU. Once that relay recieves the trigger signal to turn on a line comes from your EFI relay that then feeds the fuel pump and the Air regulator. I believe it's a GL(green and lavendar) wire. My fuel pump in my Z is almost completely disconnected from the EFI/ECCS harness. I have a 10 gauge wire coming directly from a maxifuse block in the engine bay, into a 70amp relay, then from the relay, through a 10 gauge wire straight back to the pump. The pump then is grounded at the taillight harness in the back. I just ran the original ECU wires to the relay to trigger it, but my harness is also a weird marriage of 280ZXT harness/with Z31 ECU components, mated to a 76' body harness.