NEED HELP!, D-Jetronic Wiring Harness plug into relay board Options

[Beebo Kanelle]

The Wiring harness for the D-Jetronic utilizes a 4 - pole connector to plug into the 4 - pole scoket on the relay board.

Does anybody know the specific purposes for each of the connections?

On the relay board diagram, they are labeled I, II, III, IV.

I appears to be switchable power from the relay from the power supply.

II appears to be Switched power supply bridged with IV?

III appears to be the fuel pump signal

IV appears to be Switched power supply bridged with II?

Can anybody explain the design functions / purpose for each of these poles?

Thank you in advance.

[JamesM]

Mostly right, but what specifically are you looking for/looking to do?

III when grounded activates the fuel pump relay, the rest as you mentioned are 12v supplied to different circuits of the d-jet system. Though if memory serves me correctly II and IV are powered via the starter circuit (but dont quote me on thats, its been a while since i messed with this stuff.

You can see where the pins "go" here

http://bowlsby.net/914/WiringHarnesses/HarnDia_FI_GA.jpg


but if you want to know exactly what they do buckle up and get ready for some serious reading...

https://members.rennlist.com/pbanders/ecu.h...CU%20Schematics

The links to Sheet 1- Sheet 3 break down the internal circuits of the ECU.

IF I have understood this correctly in the past...

"I" (relayed power) on the relay board are wires/pins 16 and 24 on the D-jet ECU that are primarily powering the injector drivers and triggering mechanisms.

"IV" (wire 31) provides 12v to the CSV under cranking, the other side of the CSV is then wired to the thermo time switch.

"II" tied to "IV" goes to Pin 18 on at the ECU though I dont recall exactly what it does. I think it was tied to part of the ECUs fuel pump control logic.

The Wiring harness for the D-Jetronic utilizes a 4 - pole connector to plug into the 4 - pole scoket on the relay board.

Does anybody know the specific purposes for each of the connections?

On the relay board diagram, they are labeled I, II, III, IV.

I appears to be switchable power from the relay from the power supply.

II appears to be Switched power supply bridged with IV?

III appears to be the fuel pump signal

IV appears to be Switched power supply bridged with II?

Can anybody explain the design functions / purpose for each of these poles?

Thank you in advance.

[Beebo Kanelle]

Mostly right, but what specifically are you looking for/looking to do?

III when grounded activates the fuel pump relay, the rest as you mentioned are 12v supplied to different circuits of the d-jet system. Though if memory serves me correctly II and IV are powered via the starter circuit (but dont quote me on thats, its been a while since i messed with this stuff.

You can see where the pins "go" here

http://bowlsby.net/914/WiringHarnesses/HarnDia_FI_GA.jpg


but if you want to know exactly what they do buckle up and get ready for some serious reading...

https://members.rennlist.com/pbanders/ecu.h...CU%20Schematics

The links to Sheet 1- Sheet 3 break down the internal circuits of the ECU.

IF I have understood this correctly in the past...

"I" (relayed power) on the relay board are wires/pins 16 and 24 on the D-jet ECU that are primarily powering the injector drivers and triggering mechanisms.

"IV" (wire 31) provides 12v to the CSV under cranking, the other side of the CSV is then wired to the thermo time switch.

"II" tied to "IV" goes to Pin 18 on at the ECU though I dont recall exactly what it does. I think it was tied to part of the ECUs fuel pump control logic.

The Wiring harness for the D-Jetronic utilizes a 4 - pole connector to plug into the 4 - pole scoket on the relay board.

Does anybody know the specific purposes for each of the connections?

On the relay board diagram, they are labeled I, II, III, IV.

I appears to be switchable power from the relay from the power supply.

II appears to be Switched power supply bridged with IV?

III appears to be the fuel pump signal

IV appears to be Switched power supply bridged with II?

Can anybody explain the design functions / purpose for each of these poles?

Thank you in advance.

Thanks for the response. I am looking closely at this info.

I am currently making, for my car, a fully integrated, replacement fuel injection system, utilizing modern digital technology. and, it must be able to be installed using the factory brackets and, wherever possible, the factory wiring harness, and look stock (well, mostly stock).

Right now, I got stuck as to the best way to integrate the ECM into the stock relay board, as I do not want any standalone relay boards, extraneous holes drilled, or non-stock wiring running amok within the engine compartment.