Problems when attaching Z31 ECU to L28ET with Z31 wiring harness

[Blobber]

Now I really need your help. I problems to get the z31 ecu work with L28ET engine. I'm using z31 harness to attach everything to the ecu. Engine tries to start, but the main fuel pump doesn't have any life in it. I think that the fuel pump doesn't ground itself. This because I measured 12.4V from the both of the fuel pumps poles. I have fuel pump, AFM, cylinder head temp sensor, EFI relay, fuel pump relay, CAS, fuel temp sensor, throttle valve switch(from s13 CA18DET engine) and injectors connected to the ECU. Exhaust gas sensor I don't have because the original car didn't have any.

 

I have checked that AFM and CAS has proper grounds. I have made new ground for pins 113, 112, 109, 107 36, 28 to make sure that's not the problem. What should I do next? Should the ECU turn on any lights when it turns on?

 

I attach a terrible picture to tell how I have connected the fuel pump. I have extra relay just in case.

Edited May 6, 2010 by Blobber

[6sec 6cyl]

If your testing power to the fuel pump and have 12.4v when measuring across the pump then your pump is bad if it isn't pumping. Probably due to an internal wiring fault. But like i said this only applies when when your testing directly across the pump. Hope this helps,

 

James

[SleeperZ]

If your testing power to the fuel pump and have 12.4v when measuring across the pump then your pump is bad if it isn't pumping. Probably due to an internal wiring fault. But like i said this only applies when when your testing directly across the pump. Hope this helps,

 

James

The way I read it he has 12V on each pump terminal, meaning no voltage across the pump. The ECU is not supplying the ground to the pump.

 

It's been a LONG while since I studied this, but I have a Z31 ECU and wiring in my S30. All I can suggest is to go back and study those Z31 wiring diagrams and relate it to the S30 relays. As I recall the Z31 operates the relay stuff differently so you may just have something operating in reverse of how it normally does. My car does a short prime cycle as soon as I turn on the ignition, and then turns on the pump full time as soon as the engine starts.

[Blobber]

The way I read it he has 12V on each pump terminal, meaning no voltage across the pump. The ECU is not supplying the ground to the pump.

 

It's been a LONG while since I studied this, but I have a Z31 ECU and wiring in my S30. All I can suggest is to go back and study those Z31 wiring diagrams and relate it to the S30 relays. As I recall the Z31 operates the relay stuff differently so you may just have something operating in reverse of how it normally does. My car does a short prime cycle as soon as I turn on the ignition, and then turns on the pump full time as soon as the engine starts.

 

Thank you SleeperZ for understanding my bad english.

 

I forgot to mention that I didn't use the relays which are original in 260z's electric system. I decided to use totally new relays. But I have to go and check all the connection. Does the ecu groung itself only through certain pins and not through the casing?

 

Also is it possible that the missing engine accessories could cause the problem(like the air regulator)?

Edited May 7, 2010 by Blobber

[SleeperZ]

Don't rely on the ECU case to ground. I can't remember the specifics of how it drives the pump, but I'm not sure if the ECU takes the entire fuel pump current. Rather, I think it just drives the relay, pulling the relay coil to ground through a dedicated pin. The ECU does not need most of the extra stuff; a missing air regulator will not make a difference.

[Blobber]

Now I have the main problem isolated. The problem is that ECU doesn't supply ground through pin #20 and this causes that fuel pump relay doesn't active the coil. Is there a main grounding point, which isn't seen in the wiring diagram or does the ECU ground itself only through certain pins?

 

 

Also I would like to know that should the ECU light the LED's when I turn on the power?

Edited May 12, 2010 by Blobber

[Blobber]

Problem solved. I finally found out that I had missed one 12v connection to ECU. That goes to pin 34.

[Blobber]

Next problem. Now I don't get any spark. I attached coil and power transistor to the ecu(ecu is from 86 300zx). I also removed the old wires coming to the coil. Could I this be the problem?

 

This how I attached the coil and power transistor to ECU:

 

- coil + terminal to pin 34 and 12v source from the ignition switch.

- coil - terminal goes to pin 3 and B/W wire in power transistor.

- Blue wire from the power transistor goes to pin 5.

- black wire from power transistor goes to the body.

 

Is this right or wrong? I have also tried to change b/w wire and blue with each other without any luck.

 

ECU is showing three malfunctioning codes: 23(throttel position switch), 24(neutral/park switch) and 31(A/C?). Correct me if I'm wrong, but I think that these codes shouldn't prevent the engine start?

[Daphur280]

do you have a pic of the TPS and throttle body, I'm curious I ran a ca18 TPS on my l28et and It ran horribly because of it, the tps itself was unlike any other nissan, bosch, etc TPS I came across.

 

not a good angle but you can see [somewhat] my tps here:

 

[Blobber]

I have tried with ca18 tps and z31 tps, and still no change.

 

I bought a another z31 ecu. Attached it and same thing. No spark and no voltage to injectors. Ecu lights up, when I put the key ON-position, but LED's turn off when I start. Is this ok?

 

These are connection I have made:

 

3 / pwr.transistor b/w wire

5 / pwr.transistor blue wire

9 / ignition position, which is actived only when starting

16 / fuse-> ignition key position, which is actived when key is in ON-position and START-position

20 / fuel pump relay(coil side)->ignition key position, which is actived only when starting

34 / Coil + and fuse->ignition key position, which is actived when key is in ON-position and START-position

108/ fuel pump->fuse->which is actived when key is in ON-position and START-position and Fuel pump relay->earth

 

Also two fusible links I have changed to fuses and the fuses are ok. Today I checked the wires from injectors to ecu and to the battery. They are ok. Also I flipped the chopper wheel upside to make sure that isn't the problem. Any hints?

[Daphur280]

any news?