Couple questions (lower wiring harness/body harness, pulley question) - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

wrxn240 · 12-30-2008, 01:37 AM

I've done so much much trying to do my sohc to dohc swap. I have run into some problems and am extremely frustrated.

First, are there 2 lower harnesses? I grabbed one off an auto 240 at a junkyard that connects from battery to alternator/starter/to 1 plug on the tranny. There are still like 4 plugs on the tranny and 2 plugs coming out of the fuse box. What goes to them?

2nd, I looked at the body harness connector by the ecu that I have to replace with a dohc one for the swap. Unless you can take it off the bracket and you have about a foot of extra slack, I don't see how it's possible to cut that connector and rewire a dohc one on without taking the entire dash off. any input?

3rd, I removed the a/c and p/s. Now I need a belt to go around the crank pulley and water pump. I have to wrap the belt around a tensioner too right? That's what I was told. And if so, there's no tensioner that is aligned with those pulleys. Pretty stumped on that one.

Slammed Assassin · 12-30-2008, 02:13 AM

is your car an original 5 speed?....i did this swap...easy..i need to know first if its original manual?..

anyways

1)there is only one lower harness..if your car was already manual u can use the same sohc lower harness and put it on your dohc..this will solve your problem with the plugs on the fuse box...

2) the question isnt really clear..but all u have to do is..get the body harness plug on your sohc top harness and solder it to your dohc top harness. .match up colors..some are unused..then u put it through the firewall and plug in the big blue to ecu and other plug to body harness..

3) you need to have ps pretty much...alternatives are eletric water pump (expensive)...or just put the ps pump back on and cap off the end with oil in there...

projectRDM · 12-30-2008, 08:57 AM

There is both a manual and auto lower harness, and the SOHC and DOHC harnesses are different. Use your existing harness and shorten the alternator wiring, clip off and throw away the P/S pressure switch plug. Or you can use a DOHC manual harness and plug it right in. The remaining wiring for the transmission isn't really needed anyway, run a search, there's plenty of info on this swap.

Take the glovebox out, gives you a lot more room to reach the dash plug.

wrxn240 · 12-30-2008, 06:54 PM

my car is originally a m/t but it doesn't matter because when I bought the car the tranny was gone along with the lower harness and clutch assembly, etc. so pretty much ditch the a/t harness and get a m/t one? I have to replace the connector that's part of the body harness correct? not the connector coming off the plug for the ecu, cus that's already a dohc connector. So ya that connector coming from the body harness seems almost impossible to have room to solder. And just throw on the p/s for the use of the pulley only? thanks

xpertsnowcarver · 12-30-2008, 07:18 PM

u really don't need the tranny harness. all its good for is to trigger your reverse lights. so if u don't care about that, don't waste your money. only thing to kinda worry bout is ur speed sensor. but even then... just tells ur car when to set off ur speed limiter.

the search will reveal these answers. ive been through this myself.

also, check the FSM. u can find the pdf around here to dlllll

ninja_star · 12-30-2008, 08:52 PM

i got the same problem the plug to the dashborad it doesnt plug into my dash and my car use to be a sohc how do i slove the problem of connecting the dashborad plug for the twim cam harness

daverussell · 12-30-2008, 09:18 PM

It says right above man, you need to cut the plug off the SOHC harness and solder it onto the DOHC harness. Done

wrxn240 · 12-31-2008, 02:29 PM

ok im still pretty confused about what to do about the pulley from the water pump to crank. the oem pulley i go from the a/c to water pump to crank i believe. i dont have a/c anymore....

projectRDM · 12-31-2008, 04:24 PM

Quote:

Originally Posted by wrxn240

ok im still pretty confused about what to do about the pulley from the water pump to crank. the oem pulley i go from the a/c to water pump to crank i believe. i dont have a/c anymore....

Not on any KA I've seen. The A/C has it's own belt. The water pump is driven off the crank along with the P/S pump, without it you have no way to tension the belt.

wrxn240 · 01-01-2009, 08:09 PM

ok i got the pulley situation sorted out and the body harness. I hook up the harness to the ecu and am getting no power. i think the problem may be the auto tranny harness. there are 2 connectors just coming out of the fuse box going to no where...i would assume the manual tranny harness would take care of those connectors??

projectRDM · 01-02-2009, 08:38 AM

Quote:

Originally Posted by wrxn240

ok i got the pulley situation sorted out and the body harness. I hook up the harness to the ecu and am getting no power. i think the problem may be the auto tranny harness. there are 2 connectors just coming out of the fuse box going to no where...i would assume the manual tranny harness would take care of those connectors??

Not necessarily. Depends on what plugs they are, the alternator and starter will be in the lower harness so if they're not plugged in you won't have power. But the rest of the harness, either auto or manual, is useless.

wrxn240 · 01-02-2009, 02:35 PM

there is i think 2 connectors coming out of the fuse box.....

projectRDM · 01-02-2009, 06:18 PM

Quote:

Originally Posted by wrxn240

there is i think 2 connectors coming out of the fuse box.....

Color? Size? Wire gauge? Anything?

wrxn240 · 01-02-2009, 09:39 PM

the 40 i got the harness off of had 2 lower harnesses. the normal 1 that connected to starter/battery/alt/tran and the 2nd one which connected to the rest of the tranny and then i think maybe the rest of the fuse box but idk.

wrxn240 · 01-02-2009, 10:31 PM

found out that the brown connector in the 3rd pic goes to the a/c condensor. the other 2?

projectRDM · 01-03-2009, 09:24 AM

Quote:

Originally Posted by wrxn240

found out that the brown connector in the 3rd pic goes to the a/c condensor. the other 2?

A/C drier, yes. Not needed. The other two are transmission and oil pressure sender. I don't recall the exact pinouts but you only need the VSS from those two plugs.

wrxn240 · 01-04-2009, 03:50 AM

You are speaking another language to me right now. I have all the wiring and these 2 connectors are still a mystery to me. Can I just clip those connectors and loop the wires back and call it a day?

projectRDM · 01-04-2009, 10:27 AM

Quote:

Originally Posted by wrxn240

You are speaking another language to me right now. I have all the wiring and these 2 connectors are still a mystery to me. Can I just clip those connectors and loop the wires back and call it a day?

Do you not have an FSM? Every single wire and pinout is clearly labeled within it. There's nothing to loop on either plug, you need the VSS for speed signal and that's it, but if you want reverse, neutral, and 5th gear switches you'll need to wire them. If you want the OE oil pressure light you'll need it as well. This is all common knowledge on most swap sites too.

wrxn240 · 01-04-2009, 04:00 PM

no i do not own a fsm. i don't get why they just wouldn't be part of the harness. what is VSS?

projectRDM · 01-04-2009, 07:57 PM

Quote:

Originally Posted by wrxn240

no i do not own a fsm. i don't get why they just wouldn't be part of the harness. what is VSS?

They are part of the harness. But you have an auto lower harness, which does not have the required wiring for a manual transmission, therefore you're having issues. The plugs are completely different between the two.

VSS = vehicle speed sensor. I've spoonfed you long enough, go DL an FSM. You'll thank yourself. If not, you can easily search here and online, there's a shit ton of writeups concerning this swap.

12-30-2008, 01:37 AM	#1
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	Couple questions (lower wiring harness/body harness, pulley question) I've done so much much trying to do my sohc to dohc swap. I have run into some problems and am extremely frustrated. First, are there 2 lower harnesses? I grabbed one off an auto 240 at a junkyard that connects from battery to alternator/starter/to 1 plug on the tranny. There are still like 4 plugs on the tranny and 2 plugs coming out of the fuse box. What goes to them? 2nd, I looked at the body harness connector by the ecu that I have to replace with a dohc one for the swap. Unless you can take it off the bracket and you have about a foot of extra slack, I don't see how it's possible to cut that connector and rewire a dohc one on without taking the entire dash off. any input? 3rd, I removed the a/c and p/s. Now I need a belt to go around the crank pulley and water pump. I have to wrap the belt around a tensioner too right? That's what I was told. And if so, there's no tensioner that is aligned with those pulleys. Pretty stumped on that one.

12-30-2008, 02:13 AM	#2
Slammed Assassin Nissanaholic! Join Date: Feb 2007 Location: Oxnard/SV Posts: 2,065 Trader Rating: (34) Feedback Score: 34 reviews	is your car an original 5 speed?....i did this swap...easy..i need to know first if its original manual?.. anyways 1)there is only one lower harness..if your car was already manual u can use the same sohc lower harness and put it on your dohc..this will solve your problem with the plugs on the fuse box... 2) the question isnt really clear..but all u have to do is..get the body harness plug on your sohc top harness and solder it to your dohc top harness. .match up colors..some are unused..then u put it through the firewall and plug in the big blue to ecu and other plug to body harness.. 3) you need to have ps pretty much...alternatives are eletric water pump (expensive)...or just put the ps pump back on and cap off the end with oil in there... Last edited by Slammed Assassin; 12-30-2008 at 02:55 AM.. Reason: added info

12-30-2008, 08:57 AM	#3
projectRDM Post Whore! Join Date: Dec 2002 Location: Atlanta Age: 51 Posts: 13,812 Trader Rating: (12) Feedback Score: 12 reviews	There is both a manual and auto lower harness, and the SOHC and DOHC harnesses are different. Use your existing harness and shorten the alternator wiring, clip off and throw away the P/S pressure switch plug. Or you can use a DOHC manual harness and plug it right in. The remaining wiring for the transmission isn't really needed anyway, run a search, there's plenty of info on this swap. Take the glovebox out, gives you a lot more room to reach the dash plug. __________________ FORMERLY R240NA Learn what's really going on and protect your assets now before they're gone forever: www.paypalsucks.com

12-30-2008, 07:18 PM	#5
xpertsnowcarver Post Whore! Join Date: Jan 2007 Location: LA, CA Posts: 2,667 Trader Rating: (44) Feedback Score: 44 reviews	u really don't need the tranny harness. all its good for is to trigger your reverse lights. so if u don't care about that, don't waste your money. only thing to kinda worry bout is ur speed sensor. but even then... just tells ur car when to set off ur speed limiter. the search will reveal these answers. ive been through this myself. also, check the FSM. u can find the pdf around here to dlllll __________________ My YouTube Channel

12-30-2008, 09:18 PM	#7
daverussell Zilvia Member Join Date: Jan 2005 Location: Morrisville NC Age: 40 Posts: 177 Trader Rating: (2) Feedback Score: 2 reviews	It says right above man, you need to cut the plug off the SOHC harness and solder it onto the DOHC harness. Done __________________ I never know what to put here.

12-30-2008, 06:54 PM	#4
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	my car is originally a m/t but it doesn't matter because when I bought the car the tranny was gone along with the lower harness and clutch assembly, etc. so pretty much ditch the a/t harness and get a m/t one? I have to replace the connector that's part of the body harness correct? not the connector coming off the plug for the ecu, cus that's already a dohc connector. So ya that connector coming from the body harness seems almost impossible to have room to solder. And just throw on the p/s for the use of the pulley only? thanks

12-30-2008, 08:52 PM	#6
ninja_star BANNED Join Date: Dec 2008 Location: Hong Kong Age: 36 Posts: 195 Trader Rating: (3) Feedback Score: 3 reviews	i got the same problem the plug to the dashborad it doesnt plug into my dash and my car use to be a sohc how do i slove the problem of connecting the dashborad plug for the twim cam harness

12-31-2008, 02:29 PM	#8
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	ok im still pretty confused about what to do about the pulley from the water pump to crank. the oem pulley i go from the a/c to water pump to crank i believe. i dont have a/c anymore....

01-01-2009, 08:09 PM	#10
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	ok i got the pulley situation sorted out and the body harness. I hook up the harness to the ecu and am getting no power. i think the problem may be the auto tranny harness. there are 2 connectors just coming out of the fuse box going to no where...i would assume the manual tranny harness would take care of those connectors??

01-02-2009, 02:35 PM	#12
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	there is i think 2 connectors coming out of the fuse box.....

01-02-2009, 09:39 PM	#14
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	the 40 i got the harness off of had 2 lower harnesses. the normal 1 that connected to starter/battery/alt/tran and the 2nd one which connected to the rest of the tranny and then i think maybe the rest of the fuse box but idk.

01-02-2009, 10:31 PM	#15
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	found out that the brown connector in the 3rd pic goes to the a/c condensor. the other 2?

01-04-2009, 03:50 AM	#17
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	You are speaking another language to me right now. I have all the wiring and these 2 connectors are still a mystery to me. Can I just clip those connectors and loop the wires back and call it a day?

01-04-2009, 04:00 PM	#19
wrxn240 Leaky Injector Join Date: Aug 2008 Location: Sherman Oaks Posts: 103 Trader Rating: (0) Feedback Score: 0 reviews	no i do not own a fsm. i don't get why they just wouldn't be part of the harness. what is VSS?