L20ET Engine in a 260Z - wiring help

[240Zrestore]

Hi all, i've bought a 260Z that 2 previous owners ago has put in a L20ET engine in to. The previous owner who bought it from someone else says that he was told there is an electrical problem and hence the car does not start. It looks like the car hasn't been started since the engine has gone in. Is there anyone in Queensland who is able to help me figure out the wiring and get this thing started? It looks like the people who put the engine in has had a go at the wiring and hasn't been able to figure it out.

My plan is to get the car started by spraying Nulon's "Start Ya Bastard" in to the air intake. Once i get it to start using the spray, i can move on to the fuel relays etc because all the fuel rubber hoses are currently degraded and broken. So I've disconnected the fuel pump because the last person has run power directly to fuel pump rather than going through the relay.

These are the things that i've done to try figure out the wiring.

• I've confirmed the ignition coil is good. I put power to '+' and then grounded the '-' side manually a couple of times and confirmed I can manually produce a spark with a spark plug connected to the ignition coil output
• I've run 12V to the positive side of power transistor of the "T plug" (black with white strip wire). Then I've run from pin 5 of plug 2 to the negative side of "T plug". My hope was that when i crank the engine, the ECU would ground the negative side and cause a spark from the ignition coil. This did not happen.

• I've confirmed i've got 12V at injector 6. Oddly there is constant power there on both pins of the injector connector at all times. I assume however, ecu grounds 1 pin during normal operation to get it to eject fuel.
  • However if i disconnect all of the fusible links, shouldn't i lose power to 1 or both of the pins on the injector plug? Why does it need/have constant 12V with the key in the off position/all fusible links disconnected?
• I've found the attached pinout diagram for an L20ET ECU. But i don't know if this is actually the correct one. To test if it is correct, i disconnected the fusible links one by one and checked if the power to the dash at the ON position would stay on. The only time I lost power is when Fusible Link 1 was disonnected. For perspective, I've numbered the fusible links from left to right (3, 2, 1). 
  • FYI, I only have 3 fusible links - not 4.
• I have 2 plugs with wires that comes out of the ECU and also leave from these plugs and some goes towards the engine. I've traced the wires that comes from ECU to these plugs. Please see attached picture - Plugs 2&3 tracing.jpg - and close up pics of Plugs 2 & 3. These are located at the passenger side foot well.

Let me know if you have any advice. Would love it if someone could come out and give me a hand to help figure out the wiring.

 

 

 

Edited August 30, 2021 by chaz260z

[gilltech]

So was your car actually a 260Z or a JDM Fairlady which may have had a 2L motor? Seems odd to go down to a 2L if it was originally a 2.6 (except of course it does have a turbo), as most seem to go the other way with a 2.8L for more cubes.  

Is the original wiring loom still mostly intact or has it been badly hacked about by the POs?

[240Zrestore]

Yea it was always a 260z. I checked the ID plate on it and it says L2605.

The original loom is still in tact from what i can see in the engine bay. The loom that comes out from the drivers side firewall goes to fusible links, starter motor, alternator, headlights etc and then wraps around from the drivers side to the passenger side from in front of the radiator. The end of this loom is what I believe is meant to go to the ignition coil. This end has had a few cuts and splices.

From what i can gather, the engine has its own loom that runs back to the ECU for fuel injection and all the sensors. I think i need to figure out how to integrate this loom back to the rest of the car and the ignition coil to get it running.

Edited August 31, 2021 by chaz260z

[gilltech]

Yes the very end of the loom is to the coil and distributor. Sounds like it wouldn't take much to restore it to original, simply by modelling it off another car.

One option of course would be to go back to stock or close to it by finding a 2.6 or 2.8L motor, and sell off the 2L. Do you know what gearbox is fitted?

[240Zrestore]

Nope not sure. I know it’s a 5 speed box. How do I check if it’s a 260Z gearbox or something else? Also is there a way to check what the rear diff type is?

I know the L20ET came in the Skyline R30. Maybe the gearbox and diff is from it too?

[gilltech]

If you can put up pictures of the gearbox (especially RH side), and diff installation (on a 260Z the diff is either a R180 or R200) then the forum gurus knowledgeable of such things - such as CAF - will be able to tell you what you've got.  

[240Zrestore]

Ok here are pics of the gearbox and diff. Not sure why the photos of the gearbox are appearing upside down because i turned them right way up before uploading too