4G63 Sandrail wiring help

[kocherdeal]

I am putting in a 4g63t motor in my sandrail, all I want to know is what wire off of the computer do I put 12v to and which one do I hook up my ignition switch to?

I'm a little confused on which one to hook up the 12v to is it pin 102 or 103?
Also what one do I hook up the ignition switch to pin 108 or 110? They both say switch?
Also what is the MPI ?

 

[hurricanecris24]

i would get ahold of dave DSM Forums - View Profile: dave99gst he has a 4g63 sandrail

 

[kocherdeal]

I just sent him a message.

 

[steve]

If you ever plan on using DSMLink you need to maintain the function of the MPI relay. You don't have to use the same relay but the power control for the ECU needs to be controlled like the factory setup. A regular Bosch 12v relay will work fine for both the "MPI" relay and a fuel pump relay but your fuel pump will only start running (and priming) when the ECU sees CAS signals which may cause you to crank the car more during starting.

So, you need to do one of two things. Either power the relay all the time or use a master switch but don't turn it off until after the "MPI" relay turns the ECU off.

The wiring would go something like this.

An ignition switch that runs to ECU pin 110, fuel pump input and coil, power transistor and coil.
A starter switch that runs to ECU pin 108 and to the starter solenoid.
Ground to ECU pins 101 and 106. (Both) Optional to pin 104 depending on if you want to use NTLS.
Power from the battery or master switch to the "MPI" relay input and coil and to ECU pin 103 (Unswitched Power to backup ECU RAM)
Output from "MPI" relay to ECU pins 102 and 107 (Both) and to the MAF, CAS, ISC, solenoids, and injector resistor.
Other "MPI" relay coil to ECU pin 63 and 66 (one or the other is fine).
The fuel pump relay other coil pin goes to ECU pin 56 and the output to the fuel pump and ECU pin 13.

If you use a master switch it goes between the battery and everything else. It's just there to allow you to keep the ECU from draining the battery over time. You will loose the fuel trims and all the other learned values whenever you turn it off.

If you use the factory MPI relay you get to keep the fuel pump prime while cranking feature you loose using two generic relays (because it doesn't have the second input from the starter circuit).

 

[kocherdeal]

Ok thank you very much. I'm sure I will pm you more if you don't mind when I start wiring it all up next week.

 

[steve]

If you have additional questions post them here

 

[kocherdeal]

steve ok I was missing my injector resistor pack and I found one off of a 96 eclipse it has a pig tail on it but my 91 harness has nothing for it to plug into. Do i need it? All I have read says that I do because if I don't it will burn out my injectors. How then do I wire this into my harness starting from nothing.

 

[steve]

Is your harness from a turbo car?

On a turbo car there is a red wire from the MPI relay on pin 3 of the resistor pack connector that feeds all four resistors. The other end of each resistor runs to the pin on the connector and goes to an injector.

Pin 1 Black/Yellow to pin 1 of Injector 1.
Pin 3 Red MPI Power.
Pin 4 Black/Blue to pin 1 of Injector 2.
Pin 5 Black/White to pin 1 of Injector 3.
Pin 6 Black/Red to pin 1 of Injector 4.

On a non-turbo 2.0L the wiring is slightly different. You have to trace the wiring back from the injectors to find where the four wire join the common Yellow/White from pin 1 of Injector 4 and splice the resistor pack in there.

Yellow/Black from pin 1 of Injector 1.
Yellow/Red from pin 1 of Injector 2.
Yellow/Green from pin 1 of Injector 3.
Yellow/White from pin 1 of Injector 4.

 

[kocherdeal]

Ok another question the computer that is have is this model number MD165808 is this the right computer? This is what they sent me from jdm.

 

[steve]

Ok another question the computer that is have is this model number MD165808 is this the right computer?

It's a JDM ECU, if it's a single board EPROM ECU it can be converted to run US based software like DSMLink. If it's a dual board ECU it's pretty much worthless.