R34 Gtt Neo Rb25det Wiring Info For Conversions

[DJRIFT]

Ok so firstly i hope this section will be sutable.

Second this info is to be used at your own use and i take no responsibility for any of this info being incorrect. use it at your own risk.

So after searching all over the net i realised its near in possible to get any wiring info for the R34 GTT RB25det Neo engine. I recently Did the wiring conversion in an un-named car for a customer/friend and this is the information i pieced together and put into action to make the Neo engine run off its own engine management. when we started we had no idea if it would work given the lack of inputs we had to use as far as sensors for the traction control and other other possible issues faced with the R34 GTT.

First off my example is i was given a car with a Rb25det Neo engine with its original engine wiring loom and ecu. No R34 dash loom or other wiring was supplied. the info i will post is the parts i needed to wire in to get the car to start and run on the factory ecu. The engine was never checked on a dyno to make sure everything was sweet but its pretty easy to tell.

I am also not sure if you plugged into this newly modified loom if a plug and play ecu would work. i can not see why a Apexi power FC of a haltech plug and play would not work but we did not go as far as to test this and i no longer have access to the car to try any of the above.

What you need to start with is the ECU pin out and the basic engine management wiring diagram found in the R34 GTT work shop manual that is floating around the web. If i get a chance i will update this thread with the 3 pages i had to work with whist doing this.

Basic wiring

Wires that need Batter positive.

White / Black

White / Green.... both of these wires are found in a plug on the engine side of the the fire wall Grommet. they splice off just near the fire wall grommet. these wires need a 10A fuse each. They both go to the ECM and Ignition coil relay and also supply power to pins 80 and 109 of the ECU plug

Yellow / Red... this wire will be found on the inside of the fire wall grommet (what would usualy be inside thecabin of the car) and goes to the main Ignition Relay. this needs to go through a 50A fuse link.

Wires that need Ignition (key on) supply

Dark Green... this wire will be found in one of the inside "dash" plugs. it needs to see Ignition via a switch (key) and turns on the main ignition relay.

Un known colour..... Pin 24 on the ECU plug needs an ignition Feed through a 10A fuse. the wire coming out of Pin 24 is Common to the power side of the injectors so do not cut this wire out of the loom. if you find you have no power to the injectors please trace that wire back and put power on it (un known colour)

Wires to put to ground

un known colours.... ECU pins 25, 32, 115 and 124 all need a direct body earth.

By this stage if you mark the supply types onto the ECU pin out diagram you should end up with Batter on pins 80 and 109. Ignition on pins 4, 24, 31, 64 and 72. And Earths on 25, 32, 115 and 124

that will get the engine running provided all things like crank angle sensor map sensor ect are plugged in and working fine.

Other handy to know pin outs and wire colours.

Pin 13 Most important. this output is the ground signal used to turn on the fuel pump relay.

Pin 20 Start feed from Key.

Pin 5 is Tacho out put. Be carfull with this. the tacho output is week and will not drive a standard off the shelf after market tacho. the dash in the R34 GTT is electronic and does not need to see the same voltages that the average tacho works off. i would expect that digital tachos such as the Apexi RSM should work. VDO also do a tacho that will run off it and if you can find a VDO workshop in Aus near you they can modify a stock tacho using VDO parts.

Gear box wiring.

Orange and Black wires = speed sensor. Unsure of wave form but once again they should work on an Apexi RSM.

Red and Green / Yellow = Reverse Light Switch

Yellow / Violet and Black = Neutral switch. even the manual boxes have a neutral switch which and be utilised when wiring remote start and turbo timers to stop andy in gear accidents.

Ok so i hope that has helped in some way. im more than happy to answer questions but like i said at the start i no longer have access to the car so i can not check anything elce. i have no idea what any other wires ect do or go as the job did not require me to work them out or wire them in.

the car has been running fine for quite some time now with no drams and i will update this with further info if i come across it.

[Simon-S14]

great write up, came in handy as i searched the web and couldnt find much info at all.

Now i'm trying to put a neo motor into an s14 here and followed your guide word for word. however i cant get the fuel pump to prime. Pin 13 which is a black/pink is wired correctly to the right s14 fuel pump wire (black/yellow in the F3 plug under dash)

put multimeter on it while turning the ign on to test for switched earth and im not getting anything.

now serveral thoughts as to why... you mentioned wire the Green wire up to switched ign on 12V I found a green wire in the SMJ (f3) large while plug near the ecu plug and traced this back to one of the relays so powered this up. however, there were a lot of other green wires in the same plug, and in the other smaller white under dash plug there were 3-4 green wires in this also... so, do they al need to be powered or have i wired the wrong one to 12V.

any help would be appreciated.

[DJRIFT]

Hi Simon.

this is a good question to ask as it may help others.

after looking over the wiring diagram i have found i left somthing out. there is a bunch of engine ancillaries that have a common ignition feed. this feed needs to come from the ignition switch through a 10Amp fuse on to a common wire. i dont have the wire colour listed as i must have done it and not marked it on my diagram.

So what you need to do to find this wire colour is. find the common colour that goes to the variable valve timing solenoid, the AAC valve, turbo pressure control valve (factory boost controller) and oxygen censor. there is more but you should find a common colour between the four of them. that same colour wire should be found in one of the dash multi-plugs. power that up with ignition and see if if it changes your fuel pump situation.

you will need to do this bit of wiring anyway so wire it in and report back with your findings. if you can please note the wire colour than i will add it into the first post.

i do apologies for missing it off as it was a few months after doing the job that i wrote this up, and i only put in the info that i could remember 100% other wise its just more useless info for people to sift through.

[Simon-S14]

Hey mate, got stuck into it again and Brown is the common wire your talking about, I found it in the SMJ (F3) plug on the neo loom and cut it out and gave it 12V ign on. thats now powering all the various engine ancillaries but hasnt changed the fuel pump situation,

asi said further up, im wondering i i have powered the correct green wire up as there a multiple ones to choose from and i chose the one that went to one of the 3 relays.

any help would be appreciated.

cheers

Simon

[Simon-S14]

I have 3 relays near the ecu, each with a diff colour plug, one is a brown plug requiring a unique 6 Pin relay and the other two are blue and black which use the two common blue nissan relays (or same as a common 12V 20amp 4 pin relay)

now only one is powering up. the other two have power in various spots but without a diagram i dont know what to look for,

I did spot that the blue relay (one not getting power) has a power supply going in on one side but on the other side of the relay nothing triggering it, this is also a green wire. i back traced this and found that this also goes to the SMJ plug so i cut it out and powered that up but made no diff.

so im stuck now lol

[DJRIFT]

Ok i thought you may have found this free to down load diagram. i didnt realise you didnt have a diagram. in hind sight i should have added that in.

down load from this link http://pdftown.com/PDF-Nissan-Skyline-R34-...ice-Manual.html

there is basic engine wiring diagram that i worked off. I simply added in the wire colours and worked out what was needed for a basic install.

Ok so that may help but what i can tell you is that you need the 6 pin relay to be powered up. it needs battery on pins 1, 3, 6, output 7 powers up the ignition coils, output 5 is switched power to the ecu and out put 2 switches the relay on via the ecu.

one of the 2 others will be the factory fuel pump relay. pin 13 is the switching feed from the ecu to the relay so i used that to switch the standard fuel pump relay in the car i was working on. and the other relay will be the ignition relay witch suplies a switched feed to the ecu. pin 1 should have ignition positive on it, pin 2 should have ground, pin 3 battery and pin 5 is the switched output.

two thoughts about the issue you are having. have you tried cranking the engine and seeing if the fuel pump primes then or atleast switches the wires?

And have you tried bridging out the S14 fuel pump relay so it will pump then seeing if the engine will start and run?

Also is this a known engine and ecu? we had to get a different ECU as we were getting a funny injector pulse output out of the one supplied.

Basic diagnostics: If (if) the wiring is correct and still no fuel pump out put. Try bridging out fuel pump so you have fuel pressure ect. try starting the engine. providing it runs than the fault is in the ecu.

If the engine does not run and wiring is correct than check the feeds to the crank angle sensor. pin 1 ground, pin 2 ignition positive. 3 and 4 are output sign wave. the CAS is what switches the fuel pump on.

To add to this we currently have an r34 in at work so i can check some things out on it if need be but i have been out on field work most of this week and cant get near it.

[Simon-S14]

Ok i thought you may have found this free to down load diagram. i didnt realise you didnt have a diagram. in hind sight i should have added that in.

down load from this link http://pdftown.com/PDF-Nissan-Skyline-R34-...ice-Manual.html

there is basic engine wiring diagram that i worked off. I simply added in the wire colours and worked out what was needed for a basic install.

Ok so that may help but what i can tell you is that you need the 6 pin relay to be powered up. it needs battery on pins 1, 3, 6, output 7 powers up the ignition coils, output 5 is switched power to the ecu and out put 2 switches the relay on via the ecu.

one of the 2 others will be the factory fuel pump relay. pin 13 is the switching feed from the ecu to the relay so i used that to switch the standard fuel pump relay in the car i was working on. and the other relay will be the ignition relay witch suplies a switched feed to the ecu. pin 1 should have ignition positive on it, pin 2 should have ground, pin 3 battery and pin 5 is the switched output.

two thoughts about the issue you are having. have you tried cranking the engine and seeing if the fuel pump primes then or atleast switches the wires?

And have you tried bridging out the S14 fuel pump relay so it will pump then seeing if the engine will start and run?

Also is this a known engine and ecu? we had to get a different ECU as we were getting a funny injector pulse output out of the one supplied.

Basic diagnostics: If (if) the wiring is correct and still no fuel pump out put. Try bridging out fuel pump so you have fuel pressure ect. try starting the engine. providing it runs than the fault is in the ecu.

If the engine does not run and wiring is correct than check the feeds to the crank angle sensor. pin 1 ground, pin 2 ignition positive. 3 and 4 are output sign wave. the CAS is what switches the fuel pump on.

To add to this we currently have an r34 in at work so i can check some things out on it if need be but i have been out on field work most of this week and cant get near it.

Massive help, thanks for the link, i'll give it another go tomorrow mate.

i havent tried cranking the motor, my 32 with 25 that i wired up in it in my drive primes the fuel pump for a few sec's with a starter so im going by that as to weather the 34 motor should do the same.

Cant run motor yet, no turbo manifold and lines hooked up. but i know it wont run atm with no fuel pump prime... so gotta sort that first before too much else. cheers.

Simon

[Simon-S14]

Ok after going over the circuit diagram i'm slightly even more lost.

the 3 relays i have only one is powering up and thats the 6 pin one for the ign coil and ecu relay. The other two, are doing not much, i dont even know what they are for. On the diagram the fuel pump relay pin 1 see's the fuel pump control wire from pin 13 on the ECU. i tried testing for conduity between pin 13 and pin 1 on the relay plug, and all the other pins, on both plugs and i got nothing.

same deal with back tracing pin 5 on the ignition relay plug, it's suppose to go to pin out 31 on the ECU but it doesnt on these relay pins.

the other thing i noticed is that the fuel pump relay is switched by the ecu and supplys positive power to the fuel pump. which is the opposite to all other models of nissans where its switched by the ecu and the earth is supplied to the fuel pump.

not getting anywhere here lol Also im not sure if my loom and ecu is from an Auto or manual set up.

heres a couple pics anyway.

Edited October 1, 2009 by Simon-R32

[DJRIFT]

Ok Fuel pump. Most if not all nissans switch power to the fuel pumps not earth through the relay. pins 30 and 87 of the relay are usually power and out put to fuel pump. pin 85 would have ignition or battery and pin 86 is switched to ground by the ecu. all nissan ecu switch a ground signal for the fuel pump.

i only listed the output of the ecu which switches to ground as if you are doing a conversion i would assume you would be putting in new wiring for the fuel pump or wiring it into the existing fuel pump relay. i would simply disregard the r34 fuel pump relay and only use the switched output.

second thing you need to do. you need to be switching the ignition relay so you need 2 of the 3 relays to work.

what you need to do now you have the diagrams is print off a pin out of the ecu and write down all the pins that need to have battery, switched ignition and earth. check them with a test light and any that dont have the correct feed you need to trace them back and find why there is no power on that wire.

pin numbers 109, 80 are battery.

pins 4,24,31,67,72 are ignition

pins 115,124,2532 need earth.

try them to start with then see where you are?

[Simon-S14]

Ok, ive got power at all those pins, except number 4 has power when the ign is off and then when ign is turned on, the main 6 pin relay clicks and this pin has no power, when you turn the car off the main 6 pin relay switches off after 2 sec's and pin 4 has 12V again.Im unsure if this is normal operation or not, The ECU pin out says that pin 4 is the Control wire for the main relay and looking at the circuit diagram it make sense as its on the coil side of the relay.

anyhow all the other pins have power when they should, and earth pins have earth except for pin 115 which is "Overrun clutch solenoid valve" not sure if needed or not.

Still no fuel pump prime tho! so i disconnected the starter and helded the key in the start pos thinking the ECU may need to see a start signal before it primes, but nothing. At this stage im thinking the ecu may be stuffed?

Though i would take the CAS off and with the ignition ON i turned the cas by hand and all the injectors and clicking as they should... i figure that is a damn good sign that the ecu is ok.

So there we have it, everything suggests that the car should run, but theres no fuel pump running to allow the motor to run. Fustrating!

Motor is currently turbo-less so unable to test starting it. im wondering if i just permantly earth out the fuel pump control wire if it would run or not? But im a fan of doing things properly and i figure if it isnt working i need to find out why, and fix it.

[DJRIFT]

sorry for the very long delay in my reply.

i have been stupidly busy.

anyway. yep it seems that you have all the necessary in puts that i had.

As far as the crank angle sensor goes. it is the main trigger for the fuel pump. By spinning that it may switch the injectors but not necessarily the fuel pump output. the crank angle sensor puts out 2 different signals so it is possible that one of them is not working. this is however highly unlikely.

just to clarify. the fuel pump out put out of the Ecu switches to ground so try putting one end of your test light (not multi-meter) on an ignition supply and the other end on the wire coming out of pin 13. the test light should only light up when the key is first put on then during cranking (or turning the CAS by hand)

if you dont have this and you have the CAS switching the injectors and all the other inputs and out puts than i would be looking for a new ECU.

As a further test you should also be able to test for spark when turning the CAS by hand.

To add to a question you added earlier im not sure if being an auto makes any difference but i would assume not as the latter model skylines (33 34 ) have separate transmission ECU's

[Simon-S14]

after my last test i went and plugged my ecu into a stock 34 gtt and it wouldnt run.... so the ecu is damaged.

will report back soon with findings.

[robots]

So any news ?

[Simon-S14]

yeah its up and running. ecu was the issue, got another one and it fired up straight away

[TIGERWHITEDRIFT]

Hey, I have done this conversion and followed your wiring. Engine starts fine but I can't get rid of the engine check light and Bringing up fault code 46 throttle motor sensor signal circuit and this is putting it in limp mode and running rich/retarded..,

This might be caused by not having the traction control computer or something. Any help would be great,

Thanks heaps..

[TIGERWHITEDRIFT]

Has anyone actually wired one of these up before with a standard computer without and fault codes?

[Simon-S14]

mine runs with fault codes relating to TCS and few other things but does not put it in limp home mode.

[TIGERWHITEDRIFT]

I ended up getting a stagea ecu as they don't have traction control and now I have no fault codes:) I'm surprised your not in limp mode with the faults codes. Is the engine check light on? what codes are you getting?

mine runs with fault codes relating to TCS and few other things but does not put it in limp home mode.

[Simon-S14]

check engine light not wired up but when i plug consult in i get 3 or 4 codes up. relating to lack of TCS, ABS and few others.

car drives fine tho...maybe its because its a nistune board?

[TIGERWHITEDRIFT]

What's a nistune board? It's just a standard board. Man limp mode is so bad, thick black rich smoke and won rev up. Once I put the other computer in it ran mint..