Rumnhammer

This is a closer shot of the end with the ecu plug, notice all the harness tape stripped off, and the white plastic cover that goes over the end of the ecu plug pulled back, this will make tracing wires easier and you will remove some stiffeners and hard plastic pieces that will make placing this harness where it needs to go easier later. (trust me)

This is a close up shot of the white connectors on the ecu side, the relay twins, and in the background one of those ecu pin outs you should have on hand.

This shot shows, the main injector harness overall, removed from the white connector that goes to the rest of the car. the two white connectors in the front are what goe into the main white connector that I'll show you in a minute. To the right of that is the rest of the harness as it goes out into the engine compartment note the gromet for the firewall. To the left of the white connections you see the main injection power relay and eccs relay twins, then finally left of that the ecu plug. The first thing you want to do is remove the tape and covering from the harness up to the grommet. If you are doing a 240z you need not have done anything up to this point, to the car wiring wise. For a 280z before getting to this step you should have removed the engine and all the FUEL INJECTION WIRING from the car, it's pretty easy basically all the stuff on the left hand (drivers side U.S.) side of the car. Remove it all compleatly from the car, this includes the ecu, the stock fuel injection/fuel pump relays, the dropping resistors, grommet and all that stuff. You don't need to worry about the wiring on the passenger side of the car in the engine compartment.

Ok, here we go, the following guide, is my compilation of info from this board and others that I used to do the wiring on my friends Z. I made this guide to help others with what can be the most difficult part of any engine swap, even though it is quite simple, it can be intimidating, which is why so many people opt to pay serious cash to have the wiring harnesses done, when you really don't need to. So I deceided to put together a guide that goes though the process I used to get the RB set up and running. From the get go, let me say that you will need to know how do do some basic wiring, ie splicing, soldering, and have a decent knowledge of how wiring works, like reading a schematic and using a test light and multimeter. Now just because I said that don't think it will be any harder, these are simple things and if you can put in your own stereo and feel capable of doing this swap then you can handle this part too. Next, the disclaimer, although this guide should get you running, missing something along the way or making a mistake, like not disconnecting the battery while doing something etc and frying your ecu or something similar is not my fault, so don't blame me if something like that happens. I'll be trying to make this stuff as clear as possible, but I want this guide to evolve, so if you guys find any part unclear, need a better shot of a connection or whatever don't be afraid to ask, look at it this way if you have the question, then someone else will have it too, and by clarifiying I won't continiue to get that same quesition over and over adnausium. Finally I want to thank all those that helped me, primarily Myron, Q, Zcarnut, Stony, and Matt Hutchens, and to the HybridZ crew in toto, since most of my info I gleaned from here, I just wanted to give back a bit and turn that info into and easy to follow guide. I will also try to make clear the differences between Z's and note the different ways that you can go with different Z's. The swap I did was an R33 RB25DET into a 75 280Z from California. I got the engine etc from a clip so I'll note what you need to have if you are getting an engine/tranny harness package. I prefer to pull my own stuff from a clip because you get to see the stuff before it is taken appart, and you will know the harness has not been cut in the wrong place and that all the stuff is there, but some people prefer to get an engine/tranny/harness package on a pallet and that is ok too, just need to get it from somewhere reliable. This is an RB25DET but a RB26DEtt should be similar, I haven't done that swap so you are on your own with the differences. I also suggest you print out one of the available ecu pinout diagrams availible on here to help and a schematic of the RB and the Z car will be helpful as well. With that lets go. This first pic you see the general reason why this can be intimidating. This is a shot of the engine harness that covers running the fuel injection. For Those getting a engine/Tranny/harness package, which will here after be refered to as an ETH, you will want to make sure that you have all the harness off of the engine as it goes through the firewall with the gromet and the ecu plug, this should also contain the eccs relay, and the main fuel injection relay, (they are side by side near the ecu plug) you will also need the ecu, and the main white plug that the ecu/engine harness connects to the rest of the skylines in car harness. you should preferably have about 3 feet or so of wire off the back of the white connector that would normally go to the ignition switch and other things inside the car. So if you pull it from a clip get that, if you get an ETH request it from who you are buying if from you can do the wiring without the white connector, but I found it made locating the wires and routing easier. You will also have a separate harness that goes to the tranny, alternator, starter, main hot, and IAC valve, you can do the wireing again without this separate harness and hook up the Z stuff on this side, but I found it easier to use the skyline tranny harness and splice it into the Z harness.

I have the stock one from the RB that we are not using if you send me some money for shipping, you can have it. Send me your address so I can calulate the shipping. Chris Rummel

Sweet it worked, I'll get the guide up this afternoon. Chris Rummel

Got the pics uploaded last night, so I'll post the guide as a new thread this afternoon. I'm guessing I can just post a pic with narrative posted below it, through the series of steps. I'll try and make it as clear as possible, and if anyone has any input on anything they need more clear or a different shot then I guess it can evolve and I can post a different pic to clarify. Chris Rummel ok let me try a test pic.

None of the good BOV's are cheap. whatever you do don't buy one of those nockoffs on ebay there are a ton of HKS "style" bovs and other copies that are pure junk on there. I used a HKS super sequential BOV, you may want to use a recerc valve to avoid stalling. Chris Rummel

I used the Megan racing one in the RBZ and it fits perfectly, you don't need to change a thing. 3 inch inlet and outlet, and I used the greddy intake Q45 throttlebody too. I clearanced the inner fender to add extra room for the intake plumbing on that side, and cut the hole larger to have wiggle room for the intake pipe on that side that goes into the intake manifold. I'll post a pic FWIW my friend got the Megan intercooler for quite a bit less then $400 I believe it was like ~$200 and some change. Decent quality too. Fit is perfect. Chris Rummel

So I'm real close to posting my wiring instructions with pics for the RB25 swap. I'm assuming that I just put the pics on photobucket then put the link onto here like most other forums. Just wanted to ask because I haven't posted any on here before. After i do this could someone make it a sticky? Since i have no Idea how to do that or if I would even be able to. I'll get the pics online tomorrow, and test one the hopefully by the end of the weekend you guys will have a decent set of instructions with pics on how to wire this up and have it ready to start with a turn of the key. I'll also post pics of the voltage regulator deletion and how I did the wiring for the autometer speedo, and the wiring for the harness by the tranny. I'll also post some of the snags I hit and how these things were resolved so that others that follow from here will know about them beforehand and can avoid them or get things in hand before they get to that step to make the whole deal go easier and faster. Chris Rummel

Anyone know the operating resistance range of the stock Z car temp gauge? I need to know so I can replace my RB sender with one that jives with the stock temp gauge. Chris Rummel

Thanks for the replys, I just ran a new genaric relay with 10gauge wire right to the pump works great. Chris Rummel

For the tach I already replaced it with the autometer one, it's my friends car, so I already told him that he will have to get a tach adapter, he's cool with it. for the temp gauge, I'm going to see if I can get an adapter to use the stock L-28 sender in the place of the RB sender. either that or find out the resistance of the L-28 sender and get a sender that fits in the RB spot. Andy, I used the Megan racing intercooler that has the outlets near the top, also using a greddy intake so the piping is pretty simple, I did make some clearancing dimples in the fenderwell on the inside of the engine compartment to clearance the intake side plumbing and used a plasma cutter to make the intake side opening for the larger piping. Chris Rummel

Now that the RB is running, I need to get the gauges sorted, amp and fuel still work, oil pressure works since I used the L28 sender and stock line, the temp gauge does not work, I traced the wire to show the one to tap into was the yellow with white stripe as this was the one that went out to the stock L28 temp sender. I'm thinking the resister value is different on the RB sender, normally this wouldn't be a problem and I would screw the old sender in and just use that but not only don't i have the old sender but I believe it is much larger then the sender on the RB. I had a similar problem with my friends SR20 swap into his 240sx the sr sender made the gauge peg out full hot even when it was dead cold, I solved that problem by just replacing the sender with the ka's and the gauge read correctly after that, only problem here is that size difference I mentioned above. anyone happen to know what resistance the L28 water temp sender is,and even better anyone know if any other nissan sender that fits the RB spot that is that resistance? anyone down under know? you guys seem to be pretty familar with stuff like this that pops up on RB's On the Tach I used an autometer and I know I need to get an adapter for that to work. The speedo is also an autometer replacement, I think I need to redo the hot I used for that one, since I guessed at it, and it is not coming on so I still need to sort that, once I get that to come on then I can go down the road and see if the speedo works, if not I'll try and switch the sender wires, when I asked autometer about and they said ground one and use the other as the signal wire if it doesn't register try switching them. I want to adjust the clutch too, it's engaging right off the floor which is a little hairy for a street car, having a brain fart on that one though, I believe I need to lengthen the rod on the pedal to change that right? I know that as the clutch gets a little wear on it, it will engage a bit higher, but for now it makes it a little tough to drive. Any input will be appreciated, and I promise as soon as I have all the bugs sorted I'll post pics and this info for you guys. I think the vendors that sell the wiring convertions will hate me though once I post it but oh well, maybe they shouldn't charge so much for that stuff in the first place huh. Chris Rummel

I have a Smithy that is very similar to that, and it is very useful has saved my ass a few times with my current RB swap and I've made quite a few things with it. The pro's will poo poo on it saying that 3 in 1 machines suck, but screw them, these machines work just fine for the hobbiest. They save room and are cost effective for the occational user, which I am and most of the people that buy them are. Why buy a 20K dollar bridgeport if you only do the odd peice now and then? Chris Rummel

Well the AF81 wire was the problem, The car started and ran like a top, one small fuel leak from on old bit of hose that I replaced, and a small adjustment to the idle screw at the throttlebody and we are good to go. Now I just need to get the gauges to work, I wired in the temp gauge, but I think the resistor in the sensor is wrong for the l28 gauge, and it definatly will need a tach adapter. other then that it runs pretty sweet. sounds great too. Chris Rummel

Thanks to all, I'll get some power going to the injectors this afternoon when I get a chance to work on the car, hopefully this evening I'll be posting all is well. Q, family and dog doing well thanks. I'll post all the wiring for this and the gauges as soon as it runs, I've been waiting to post just in case this type of thing popped up. I don't want to post anything that leaves you hanging. I just looked at the schematic again and found I wired the check engine light backwards so I'll have to change that too. I think I'll post pics of the exhaust I made too, it turned out really nice, for the downpipe I had to add an inch and half of length to the downpipe section because the engine fits about an inch higher in the Z then in the skyline. I also added a secondary O2 bung in the downpipe and I'm glad I did too, because I'm using the JDM HKS upper downpipe and with that one the O2 sensor just missed the steering rod, in fact once the car was on the ground it touched the locking bolt on the steering rod, so I moved the O2 sensor to the lower bung. Chris Rummel

I spent most of this evening going back over the schematics, I think the coil wiring is good to go, since I know for sure that those relays for ignition are getting power (did lots of tracing will check for sure tomorrow) I'm thinking my injectors are not firing, because the only thing I didn't power up was the AF81 wire, was thinking it was connected already from the other AF36 wire, but on the schematic it shows it's not, and in the wiring for going into a 240sx they make note of wiring it into the AF36 wire separatly so I think that is what my problem is. I haven't had someone crank it while I listen, but as much as I've cranked it, if the injectors were firing, I should be able to smell raw fuel at the tailpipe from the fuel being cycled through without being burned and I dont' smell the raw fuel, so that combined with knowing that I haven't powered up the AF81 wire makes me think that the injectors are not firing. I guess I'll find out for sure tomorrow. wish me luck Chris Rummel

Cuz is was getting dark and cold, plus what is the easiest way to check on for spark on the RB? I'll try and listen for the injectors tomorrow, figured I'd do better to sleep on it and try fresh tomorrow. And since I figured I could save some time by posting on here to see what you guys thought, before I go down the wrong road so to speak. Chris

Hi all, got to the point of starting the car, and it is not firing! I have all the wiring checked, the fuel pump is turning on for 5 seconds to presurize the rail then turning off like it should, I directly grounded the relay to keep it running while I tried cranking it and still nothing so it is not a fuel delivery problem, at least not at the pump. So it is either the injectors are not firing or I have no spark. The car is cranking over fine, just not firing. any suggestions? Chris Rummel

Yeah, I figured that weight differnce, turbos are heavy. but bob is calculating an intercooler to be 50 extra lbs? I don't think so not even with all the intake plumbing. My point is that I rather doubt it is 200-250lbs difference dressed, much less without turbos etc. Chris

Do you have any real weight difference numbers on that or are you just guesimating? I remember that L28 I pulled out was pretty friggin heavy, both engines are Iron block, aluminum head 6's of very similar dimentions, I really rather doubt that it is 200lbs difference. The RB25 tranny is beefier but I don't think there is that much differnce weight wise. An L24 might be a bit lighter because it doesn't have any fuel injection stuff on it, but the difference is very little. With the Rb you have a second cam and a wider head, but the real weight is in the block, both have a simlar block size and weight, any real difference is likely in the larger RB tranny, but I doubt it is 200lbs worth. Chris

Ok, nearly done the swap, so after I get it started and running this week, I'll post the pics, etc. I want to make sure it starts up and runs properly before I post stuff, so that you can follow in confidence. I just want to make sure everything is good to go. I'm at the point of just adding fluids now so it won't be too much longer. Chris Rummel

Motorex is done, the owner got busted for all kinds of nasty things. Chris

I got my front clip from Japan Direct in North Carolina, was just over $3k shipped for a R33 RB25DET clip, with only 58k miles on it. the entire clip was in excellent condition. Fast delivery too!! I would highly recomend them. Chris Rummel