RB20DET Wiring Conversion. Help Identify This Plug/Part

[xxsptcuztomsxx]

First of all i have searched through both the R32 engine service manual and the r32 gtr sworkshop manual (shows wiring for the rb20det ecu).

The manuals can be found at
http://www.importworkshop.com/files/man ... manual.pdf
http://www.importworkshop.com/files/man ... manual.pdf

Im swapping a rb20det into a s14 chasis. I need assistance identifying a couple plugs/wires/parts. Im attempting to clean up another inidivuals attempt at the wiring and removing all the uneeded wires (not running a/c or consult).

The first item i have a question about is pin 104 on the ecu connector. Its a green w/ white stripe wire that goes to the white 12 pin conector on the rb harness. In that 12 wire connector there are 5 wires out of the 12 pins that are actually used. Light blue, orange, white, black, green/white. In the FSM it list the wire as
Fuel Pump Volt Control Output. The fsm shows this wire (pin 104) going to the Fuel Pump Control Modulator (pin 1) (FPCM) Is this wire needed?

Secondly, comming from the same 12 pin connector on the RB harness there is a white wire and a black wire that goes to what looks like a resistor pack of some sort. What is this box and is it needed?

Finally, comming from the 12 pin connector on the RB harness there is an orange wire and a light blue wire. These two wires terminate at a 6 pin plug on the RB harness. What are these for and can they be eliminated?

I guess with all that being said....what i'm really asking is...... is the silver resistor box looking item, 12 pin RB connector, 6 pin RB connector required for the motor to run?

Below are pictures:

Wire comming from pin 104 on ecu connector.


12 pin connector on rb20det harness.


Silver resistor pack? white & black wires.


6 pin connector on rb20det harness that orange & white wires from the 12 pin connector terminate at.


Any help and/or input would be appreciated...... CarlH this means you!

Sry for the quallity of the pics...cell phone pics

[xxsptcuztomsxx]

so i think the box part is the dropping resistor. Since the two wires comming from the dropping resistor go to the white 12 wire RB plug and do not go anywhere else....and assuming that same 12 wire plug doesnt go to anything...can this item be removed? im hoping someone with a bit of expierience will chime in soon..im driving myself insane searching through the schematics in fsm trying to get this situated.

[RustspecS13]

I believe its for the wiper motor on the R32, or something else for the chassis. The RB25/R33 integrates the wiper wiring with the engine harness, and I think the R32 started with that box. I removed mine and its fine.

The other connectors I don't really know or care what they are for. There's some stuff that seems to run though those connectors, but none of it is needed in a S chassis swap as it doesn't do anything.

~Alex

[wrgibson]

+1 w/ Alex
I'm not running that silver box and have no ill effects.

[TheRBguy]

You need a dropping resistor on an Rb20 or you will fry your injectors in time.

[RustspecS13]

That resistor in question is a 2 wire resistor. It goes no where, just through the firewall grommet to a plug near the ecu. Its connected to nothing.

A injector resistor box usually has 6 or 7 wires, and raises each injectors resistance.

Stock RB20DET injectors are high impedance, so they wont fry anything. Unless your mixing oem skyline parts but what else would you expect if you didnt do it right?

~Alex

[TheRBguy]

An Rb25 is high impedance Rb20 and 26 is low impedance. I have looked it up.

[xxsptcuztomsxx]

Thanks for the replies fellas...

Im almost certain the pictured resistive component isnt used for anything....i've deloomed the entire harness and traced the wires comming from the resistor and they end at the 12 wire plug that has the orange and teal wires going to it...and that connector was taped up from the previous individuals attempts at the wiring..it looks like he had that portion correct.

[RustspecS13]

An Rb25 is high impedance Rb20 and 26 is low impedance. I have looked it up.

The RB20 is high impedance, I own one. Plus I didn't just read it, I've ohm tested my injectors personally. They are quite assuredly high impedance.

cuztoms- I eliminated all that extra wiring from my harness. I cut it off at the firewall grommet on both sides since I couldn't pull it through. It looks a lot cleaner now.

PS my car runs fine, no electrical fires or anything.

~Alex

[xxsptcuztomsxx]

sounds great..thanx for all the input. i'm convienced these few extra plugs arent used for an s chasis rb20det swap....i've verified the various replys to this thread and most of them are correc...per FSM's..

thanks for all the help thus far....now wish me luck with my harness cleanup and wiring.

[Carl H]

An Rb25 is high impedance Rb20 and 26 is low impedance. I have looked it up.

misinformation then, all nissan eccs systems are high impedance BUT some turbo motors have low impedance injectors requiring the use of a resistor pack, notably the CA18DET and the RB26DETT.
Rb20 runs std high impedance resistors, the resistor he was inquiring about is tied into the skyline's variable voltage fuel pump regulator.