79 280zx efi problems

Discussion in 'Electrical and Ignition: Repairs and Modifications' started by 280zxSheik, Sep 24, 2013.

  1. 280zxSheik

    280zxSheik Member

    I started another thread about my gm 3800 v6 swapped 1983 280zx where i, on a tangent, mentioned efi problems on a 79 280zx w/an l28e I'm having as well, unfortunately the 79 has evolved into a bigger project so i decided to dedicate its own thread to it.

    So here is the run down okay on the 79 datsun 280zx electrical problem. The fuel pump wasn't turning on. the wiring between the fuel pump and relay 1 (green and black wires) is good, the green with white stripe between relay 1 and 2 is good, and the black with red strip coming from the ignition is good. the fuel pump sees 2 volts when in ACC, 0 volts in ON, and 9 volts (basically 12 but the starter is lowering it) under crank. are there any other wires involved that could be severed or any components not working. possibly a bad ground or bad relay?

    To solve this temporarily we bypass the the wire that closes the Fuel pump relay, thus allowing the fuel pump to turn on when the key is in on. The car cranks but won't start, even with the operating fuel pump, pressure at the rail and spark. We now noticed the injectors aren't firing. We are gettin no signal/volts at the injector harness & the efi relay clicks but im not sure if its sending signal.
  2. grumpyvette

    grumpyvette Administrator Staff Member

    if you suspect the injectors , you first use a multi meter to verify every injector reads the same ohms (usually near 11-16 ohms, and yes they should all read very closely) then you need a noid kit for a G.M. fuel injection system, these are basically little lights that light as the injector pulse hits them that you plug into the injector harness,after you remove the harness from the injectors, they plug into the harness just like an injector, if you try to start the engine and they blink on and off the pulse is reaching the injectors thus proving that the injectors get the pulse

    http://www.harborfreight.com/11-piece-n ... 97959.html



    http://members.shaw.ca/corvette86/FuelS ... gnosis.pdf

  3. 280zxSheik

    280zxSheik Member

    I'm sorry if i didn't clarify. The 79 zx has the original nissan l28e in it. Will this tool still work? If so i will buy it 2moro!!
  4. grumpyvette

    grumpyvette Administrator Staff Member

    if your injectors have similar connectors to the ones used by most G.M. cars the NOID lights plug in and should work.
    the noid male prongs fit the connector female sockets
  5. 280zxSheik

    280zxSheik Member

    I went an got the noid kit n tested an im gettin nothing at the harness.
  6. 280zxSheik

    280zxSheik Member

    Okay here is the update:
    I tested the efi relay and its working and the harness from the relay is getting 12v when i crank the ignition. Tracing the the relay's wires they all run to the pcm, which then terminates at the injectors, uninterrupted. Is it possible the ecm is bad?
  7. grumpyvette

    grumpyvette Administrator Staff Member

    yes it is possible, even likely , but ID suggest checking the FUSES and GROUNDS CAREFULLY before assuming its the COMPUTER

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