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LS SWAP 280Z e A few questions for the wiz's

Corvette 280z LS Harness Questions

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#1 TheZkid

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Posted 26 October 2016 - 11:01 PM

Welcome gentleman! (+Ladies?) I have had my '76 280Z for a few years now. Ran a bigger turbo L28 for all the time I've had it. I have recently restored the body and paint, I now need the heart and brains to go with this broad of mine. I have just pulled out my L28 and now need to have a few questions answered. Here is my situation:

I can attain a full GTO/C5 LS2/T56 from salvage auction.
Or I have a few local engine options I can go with. But I can't find a T56 for the life of me (in Canada, just over the pond from Detroit, A.K.A the gutter of Ontario)

First question: I have taken the ECU box of out the drivers side and fed the engine harness through and have taken it all of from the engine. The passenger side however - do I take ALL of the harness out? The pass. side routes to the starter, body grounds, this junk fuse panel (for lights?) alternator, lights, turning signals, etc; do you guys take that all out and run a whole brand new harness from the passenger side connections under the glove box? I've heard of the EZwiring kit, is that something to run for the lights/signals with the LS?

Secondly: if I were to go with the LS2 from the salvage car is there somebody or a company that revamps the harness for these engines?

My goals for this swap are simple. Have a GOOD running engine and car in a whole. I don't need a wireless engine bay, just clean. I don't need over 450hp either. I want the engine and harness set up to be reliable as possible for I am wanting to go on long drives with this and drive it almost daily in good weather.

I want everything I need (aside from odds and ends)before I start putting the LS in. I am going with the JCI mounts and drive shaft for what it's worth as well. I have a good amount of money set aside for this whole ordeal, it my 4th engine swap (rb20, SR engines previously) so I know how somethings are done,! but I do not want to cut any corners with this swap. I want things done right and done right the first time. I have also been looking at a million threads on this but I can't seem to find a few things I want to now. I already have more questions but I want to see the reply I get with this first.

Thank you very much for your time and effort in advance. Cheers.

#2 NewZed

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Posted 27 October 2016 - 05:45 AM

First question: I have taken the ECU box of out the drivers side and fed the engine harness through and have taken it all of from the engine. The passenger side however - do I take ALL of the harness out? The pass. side routes to the starter, body grounds, this junk fuse panel (for lights?) alternator, lights, turning signals, etc; do you guys take that all out and run a whole brand new harness from the passenger side connections under the glove box? I've heard of the EZwiring kit, is that something to run for the lights/signals with the LS?
 

Why would you remove general car function wiring to do an engine and engine management system swap?  You're getting distracted.  Wires provide power or control signals for functions.  Focus on the functions.



#3 TheZkid

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Posted 27 October 2016 - 06:14 AM

Every guy doing this swap I see has taken out every piece of harness to replace it with a new one?

#4 NewZed

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Posted 27 October 2016 - 06:22 AM

You should ask "why?".

 

Here's a good swap thread - http://forums.hybrid...-mentor-wanted/



#5 wayverippah

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Posted 27 October 2016 - 08:43 AM

When I did my swap, I yanked the entire harness... But I wanted to rewire everything because i'm anal. You can leave it in and just use the GM harness for engine function. You really don't need to modify anything (GM got it right), just get HPTuners and remove VATS. Going with a T56 makes things even easier since you don't have to deal with the harness for an automatic. Also, use a drive-by-cable throttle body to make things easier (LS2's came with both drive by wire and drive by cable).

 

Also, take note that GTO T56's are slightly different than FBody T56's. Both work, but will take a little modification depending on which one you get.



#6 TheZkid

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Posted 27 October 2016 - 05:10 PM

When I did my swap, I yanked the entire harness... But I wanted to rewire everything because i'm anal. You can leave it in and just use the GM harness for engine function. You really don't need to modify anything (GM got it right), just get HPTuners and remove VATS. Going with a T56 makes things even easier since you don't have to deal with the harness for an automatic. Also, use a drive-by-cable throttle body to make things easier (LS2's came with both drive by wire and drive by cable).

Also, take note that GTO T56's are slightly different than FBody T56's. Both work, but will take a little modification depending on which one you get.


Thank you for your reply. Reasons why I want to pull everything is because it is a pretty junkie harness and I'm also selling it to another guy. I'm wondering if I pull the passenger side, can I get the EZ harness and run new wires to my lights and signals. Am I right when I say the GM harness covers both sides of the engine so I don't need anything from the Datsun harness to go on the ENGINE of the LS.

#7 trackzpeed

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Posted 27 October 2016 - 05:47 PM

I left the datsun harness in place..... I used wiring specialties ls1 plug and play to get the motor to run. Works perfect IMO.

#8 wayverippah

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Posted 28 October 2016 - 04:15 AM

Yes, the GM harness will control the entire engine.



#9 TheZkid

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Posted 28 October 2016 - 05:05 AM

Problem is the whole harness is taped together with a mess and I am selling my whole harness to this guy. Can someone please answer me if I can use the EZ wiring just for my lights and signals?!

#10 hornedcow

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Posted 28 October 2016 - 12:14 PM

I cut everything out of the front harness except for the lights and wipers. Time consuming ...



#11 Richard Oben

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Posted 29 October 2016 - 04:22 PM

The engine harness goes to the UHFP (under hood fuse panel) so it can run the fan, AC etc.  If you dissect just the engine parts the rest can be sold.  I know that sounds simple but the harness needs three wires to run, HOT, Ign hot, ground.  It should have a fuel pump out, OBDII out, VSS, AC request and a few others I can not think of at this moment.  I can tell you this.  LS1 tech is so your friend on this stuff.  HTH, Richard. 



#12 30 ounce

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Posted 30 October 2016 - 05:51 AM

I left the datsun harness in place..... I used wiring specialties ls1 plug and play to get the motor to run. Works perfect IMO.


On wiring specialties website it says that their harness works with the stock gauges...is that correct? That by itself would make it worthwhile for me.

#13 hornedcow

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Posted 30 October 2016 - 06:01 AM

On wiring specialties website it says that their harness works with the stock gauges...is that correct? That by itself would make it worthwhile for me.

 

I would assume that means they just give you wiring for the senders in their harness. You'll still need metric adapters and re-use the stock Z coolant and oil pressure sending units if you want the stock gauges to work. Tach might be able to be made to work but not going to be plug and play. And you have no speedometer cable so the two main gauges are not going to work. The fuel gauge will work if it did before (ha) and the amp gauge will work if you wire everything through it electrically ... I bypassed it all and did new gauges.



#14 CableSrv

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Posted 31 October 2016 - 12:01 PM

I currently used the painless wiring kit to work my main harness and used shevythunders standalone harness for the LS1


1971 240z

98 LS1 with T56, Johns Car's kit, JTR headers, JTR intake ducting, ChevyThunder's standalone harness, Custom 3in exhaust with straight through muffler


#15 trackzpeed

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Posted 31 October 2016 - 06:16 PM

No that's not very accurate. I swapped out for a new speedo and tach. I used the everything else datsun for now but it was all as said before with making the datsun sending units work (oil pressure, water, volts, and fuel-reads backwards with my cell sending unit). The wiring specialties was only for the LS and T56 to work.

#16 NewZed

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Posted 31 October 2016 - 06:26 PM

Problem is the whole harness is taped together with a mess and I am selling my whole harness to this guy. Can someone please answer me if I can use the EZ wiring just for my lights and signals?!

With wiring, if you have to ask these kinds of questions you probably shouldn't be attempting it.  The Hazard switch alone foils most people.  You're probably replacing the wiring because it looks bad.  But it probably functions fine.  I'd leave it and do the engine harness alone.  That effort alone will help you decide if you want to tackle the body harness.  The engine harness should feel like a piece of cake.  If it doesn't, think twice about the body harness.



#17 Richard Oben

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Posted 01 November 2016 - 08:41 AM

What NewZed said.  The questions you are asking are good ones, but they are fairly beginner questions, my guess is you are young and enthusiastic which is good.  

 

NOTHING IS PLUG AND PLAY, PERIOD.  NO CURRENTLY AVAILABLE HARNESS WILL SWAP INTO THE Z EASILY.  

 

We have wired cars from start to finish from the ground up, the simple stuff is simple, keeping things like hazards, interior lights, etc working correct are harder than they appear.  In one car we built we used a Corvette engine and fuel tank harness and tied it to a painless (oxymoron if there ever was one) chassis harness for power windows, lights etc.  It took days and days to get it all tied together and we still had a few gremlins.  For the Datsun 240Z I had my LS1 GTO engine harness cut down (computer refreshed also), current plan is to use the Z chassis harness and update the gauges to match the LS1.  HTH, Richard. 



#18 Ryan Merrill

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Posted 02 November 2016 - 06:32 AM

There are kits to drop in your engine. There are pre-made, 3 wire hook up stand alone wiring harness for $600-$800 that can be purchased online. You can save a ton of time that way. I personally and god with tearing apart a harness, removing what not required, adjusting wire length, re assembling connectors, wiring everything require to a fuse box, etc. If you want the car running quickly just buy the pre made stuff. Elimintate many of the issues by DIY.

 

If your poor like me, here is a good place to start for the harness  http://lt1swap.com/



#19 TheZkid

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Posted 02 November 2016 - 08:06 AM

I currently used the painless wiring kit to work my main harness and used shevythunders standalone harness for the LS1


Yeah I'm going with a "plug and play" harness. I know there's going to be some modding with both options. If I don't go with a brand new one I'll send my stock one into get revamped. Is there a go to new plug in harness for an LS1? I see a lot of different set ups, Chevy thunder, wiring specialties, painless, etc; I don't have a problem spending the money to really cut down on the messing around with the wiring. That's the one thing that will give me a snag on this swap. All the mechanical things will be fine.

#20 RebekahsZ

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Posted 02 November 2016 - 06:06 PM

The wiring you will need is a fuse panel for items that you want got all the time, items got only with key on, and a ground. You will need relays for fans and fuel pump. Those are the car side of things that you will need regardless of what you do with the engine harness.

1972 240z, purchased in 1991 for $900. Bone stock LS2/T56/DBW from 2006 GTO, swap completed in 2011. 400rwhp/435 rwtq. 2400# minus driver. JCI swap, Mantic ER2 clutch kit, JTR headers, single exhaust, Borla muffler, MGW shifter, M2 Differentials shortened Z31 CV axles, Z31 CLSD R200, Chequered Flag Racing billet stubs and companion flanges. MSD 2-step, Hurst roll control, both operated from switches on clutch pedal. 9" Hoosier drag slicks on Weld Draglites, 245/45/16 Hoosier A6/R6 on 16X8+10 Rota RBR. 225/250 sectioned coilovers, Koni 8610-1437RACE shocks, DP and EMI camber plates, MM shortened rear control arms, TTT front control arms, poly and aluminum bushings. Top speeds: Ohio Mile 174mph, C/GMS class record holder, best 1/8 mile 6.96 at 100mph, best 1/4-mile 11.0 at 126mph, best 60' 1.43, best 1/2-mile 148mph at GA 1/2-mile. Home Track-Jake's Dragway, Moulton, AL. SCCA autocross club - TVR, Huntsville, AL. Lets race!






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