RB 25 DET engine in A31 Cefiro problem

[Pascal]

Hello everyone! I have one small question. I did buy engine RB 25 DET from Skyline 33 with A/T (automatic transmision). Now i did put that engine in Nissan Cefiro A31 witch is manual transmision. All working except injectors! When i give signal to injectors manually (witch is minus, and comune is positive that is all time ON since ignition with key) car works witch leads me to conclusion that ECU (ECM) dont wanna turn on engine because some reason. My idea is that there is no signal anymore from A/T (automatic transmision) if the gear is in P (parking) or N (neutral) so for safety reason ECU(ECM) does not want to give signal on injectors, therefor turn on engine! I did got already wiring diagram from one friend of mine here on forum. Now i would like to know witch wire to put togheter (to make bridge) to simulate to ECU that gearbox is in P (parking).

 

Congrats for forum! I think i will stay here for long long time!

[Z U L8R]

i just fixed the same problem on an sr20 car the other day. the coils were firing, fuel was going to the rail, it was also a used to be automatic but now a manual, so bridging the park/neutral safety switch was necessary to complete the signal to the starter solenoid. everything else worked, it would turn over but not start. the injectors were getting power but they were getting no noid (ground) signal from the ecu, therefore they would not pulse. the problem was the feller who did the guy's wiring didn't wire in the dash plug correctly, hell he actually wired it in to different plug altogether LOL. with that done, aside from the guages wouldn't have worked and ac request also, the problem with that - that was not allowing the car to start- is the START SIGNAL WIRE, on the sr20 it is orange, i beleive on my r33 skyline rb25det it was grey with a red stripe. good luck

 

i can't say whether you do or don't have a bad ecu without being there to diagnose your car, but i would start by making sure the grey/red stripe wire is getting it's signal first. and then again even before you condemn the ecu, look into the problem being in aftermarket security systems and go from there.

David

[Pascal]

I am missing that small module that is near ECU, or to say more precise, that module that is on the way from engine to ECU(ECM). So there is like 10-12 wires that goes from engine first to that box(maybe some relay box??) and then from that box to ECU(ECM). What is moust interesting is that from ECU, pin nr. 5, 14 and 15 goes to that box that i am missing! That wires is know as signal from A/T!!!!! So how can even imagine my ECU that is car in P (parking) o maybe N (neutral) to allowe firing of engine, right?? As i am missing that module i need to get idea witch kinda info is sending that box (maybe relay?) to ECU about status of gear-box? There is 3 wires, one of them should give minus (-)??, one of them (+)??? and of them maybe just connect to VBATT?? Or somethingelse? I did try already to connect them togheter or each by each and no results. Obviusly should be closed some circuit to give command for firing the engine. In that circuit is proly one positive(+). But witch one??

Thankh very much for help and on the end tht will give me posibility to write dopwn one completly new wiring diagram for RB engines that could be useful to some users maybe!

 

Best regards Pascal

[Z U L8R]

i've never seen a cefiro wiring harness so i'm not sure what you mean by the "box", off of the main engine harness there should be the big blue ecu plug and the small white plug, which i call the "dash plug". on that dash plug is where the grey/red stripe wire should be. unless you wanna fry your ecu please don't add power or ground to random wires LOL. could you take a picture of the "box" or connector that goes to the "box" so i can be on the same page as you, thx

 

i love diagnostics, you learn so much

[Pascal]

I think we are talking about same white jack! Big blue for ECU and that smaller white jack! That jack should be used to connect to some small box that control dash? I think is also used to control IGN with ignition key, when you wanna turn your car on, right?

So as i dont have that box on this Cefiro cause is old carburated vehicle, obviusly i dont have it! But is NOT box like i think bot its goes to another small harness that goes to dash and key and stuff, right???

OMG! So i really need to have idea about that specially to be able to fire my car! BTW. first time in my life i do things with one Nissan^^ so thx for underestanding. Engine is now builded on 437 hp with TDD ECU and i would like sooooo much to test stock one! People say is really good one.

 

Cheers Davide

[Z U L8R]

well, then you're in luck

 

that dash plug has a lot of functions, it does get ignition power in order to kick on the 2 blue relays which one sends power to your ignition coil and one sends power to the ecu, it also has the speedometer, tachometer, and coolant temperature signals for the guages (some of those features may not be compatible for your set up however they won't interfere with your car running and driving), it also needs start signal, it also powers your idle air control valve, o2 sensor, etc etc. if certain wires from that plug haven't been wired into your vehicle then your motor definately won't start hehehe.

 

the good thing is there's a sticky up there it says CHRIS RUMMEL'S WIRING RB25DET or something like that towards the top of this page, and chris has pictures and explanations of how to wire in that "dash plug." it's for a Z BUT, it's basically the exact same thing, the only difference is he's doing it on a Z ignition switch, and you'll be doing it on your cefiro ignition switch. you may have to use longer wires in order to tuck the ecu away etc but the whole concept is the same. familiarize yourself with your ignition switch and what wire does what, then follow his instructions and you should be ready to roll. keep us posted

[Pascal]

Hey David! Maybe i am bad to explain my self cause my English is not so good. I apologize for that to everyone!!! What i actually need is to know how the hell make ECU work! I mean, when i give my self negative signal to the injectors everything is perfect, but that is for ECM there! And dont wanna di it cause there is no signal that is gear in P (parking). What i need to know now how or where to bridge 2 or 3 wires to make ECM believe that is gear-box in P (parking) so he will start to give signal to injectors! I did try also with that grey-red wire but i am not sure witch kinda signal to give. Conect to + directly? I did try even that but no answer from ECM! SIGH! I know that guys in Hong Kong do almost everyday that stuff but for me is not now posible to go there and search for answer. BTW. if anyone need some RB engine just lemme know. Its cost like 2000 to 3000 US $. Mine i did pay 1700 USD.

Here is some pics to see that we speak about same thingy. Thx for u'r patienty Davide and unfortunatlly i did not saw it nothing on that page that can help me. For me is just important that engine works. Later i will easy do rest of it.

 

 

I hope we did talk about same white jack

 

[Pascal]

here is photo. Sorry but i am not good with putting photo. hehe

[Pascal]

ufff. still not photo shown. Someone can help me how to post photos please? I apologize for mess that i did it.

 

Best regards Pascal

[Z U L8R]

as far as the grey/red stripe wire you're going to wire that into a wire that gets 12v+ when the key is in the "START" position. you can wire that into the ignition switch, usually nissan is a thick black/yellow stripe.

 

the NEUTRAL SWITCH signal goes to pin #44 off the ecu it should be GREEN/ORANGE stripe (nv11), it taps into the dash plug where it's still green/orange and the dash plug calls it CQ51 and the green/orange wire also goes to an 8 pin plug named A-17. as far as the green/orange wire it doesn't matter where you tap into it, GIVE IT GROUND sorry for the misunderstanding

David

[Z U L8R]

one other question, so your wiring harness that goes through the fire wall, you have the big blue ecu plug, you have 2 blue relays, one big ground eyelet with a bunch of black wires going to it, you have one white shaped "dash plug" and you also have ANOTHER connector going to the A/T computer BUT YOU DON'T HAVE AN A/T COMPUTER?

 

hypothetically on any car that has a separate computer for the automatic transmission, if you unplug the A/T computer, turn the key to the ON position, and manually apply 12volts to the starter solenoid, the car should start and run, therefore, if you have the ecu getting power and grounds correctly regardless of if there is an A/T computer present or not, if that starter will turn the motor over the engine should run and start. this may not even be a problem for you.

 

if it still doesn't start after you wire in the grey/red wire , and ground the green/orange wire, double check the 2 grounds towards the front of the engine that are on the intake manifold. if it still doesn't start then the "dash plug" is not wired correctly. good luck

[Pascal]

I dont have nothing on that "dash plug"! I dont even know what should go there! hehe First time i hav fun with one Nissan and make my self trouble cause i really wanna work this, stock one ECM, not just with TDD. TDD or MoTec is for dummy's. So i just wanna fire up my engine. Later to connect gauges or anything will be no problem cause will use all after market! So anyway that old system from Cefiro is not anymore impotant for me. Also its till 180 K/MH and now car can fly 265 as we measured with TDD ECU or with MoTec hehehe. So not even anymore use of that gauges. Thanks very much David! Will keep you informed and i will try to learn how to post pics! Will be interesting i think on the end of story!

 

Best regards Pascal

[Z U L8R]

ya, you have to connect the dash plug wires, wire it into your cefiro just like Chris Rummel does on the Z. follow his instructions -"CHRIS RUMMELS EASY TO FOLLOW WIRING AN RB IN A Z"- on how to wire in the dash plug into the ignition switch. if you do it how he says your car will start , not a problem helping somebody, anytime, take care

David

[Pascal]

Hey David! My problem still exist! I did connect many of those wires but seems to me that i must start to work my way cause i cant get help this way. What i would like to know if someone have diagram of ECM(TCM) inside so i can pull list of cmd witch is necesary to make work that ECM(TCM). You know, i work with ECU's for a long time, like maybe 14-15 years now, but my problem is here that i dont deal with stand alone ECU but with already configured ECM(TCM) that i cant change or see anything. If i can only find data or information what is REALLY necesarry to make work this ECM(TCM) then i will be done in proly 10-15 minutes. To me is missing only 1 or 2 wires that i need to put somwhere to tell ECM(TCM) that now can start to give pulse to injectors!! All other things work perfectly! I also dont have ECM(TCM) and that "dash plug" inside of cabin cause cant reach inside, so i will leave it in engine bay! I would like very mjuch to send you somehow pics from car and ECM(TCM) and wiring diagram that is correct! But dont know how. And so on with many other things! hehe

[Pascal]

i Hope here is photo of two connectors that i dont have conected. And here is from my ECM(TCM) and that dash conector photo. So as i dont have any wiring to make from my dash connector i would like to know witch is wire really necesary to connect and witch type of signal. BTW. mine is R33 RB 25 DET and does NOT have any other box, that why in version of A/T is called ECM(TCM). TCM is for transmision control management. Other wiring diagram that is have is same but for M/T, so also name of ECM is only ECM and only difference is that on that wiring diagram is presented also module for automatic gearbox. Hopefully this is enough info this time. Sorry again for my bad explanations David.

 

Best regards Pascal

[Pascal]

Oh... and another question, from pin 104 goes one wire to one box with name FPCM?? and is writen on wire that is exactly for RB25DET, so my enigne obviusly. What to do with that wire? BTW. Car does NOT have any alarm or something and basically can even have but my harness is completly divided from car so its does not matter. Also i did pull out one wire witch i use for cranking.

 

Best regards Pascal

[Z U L8R]

the first pic none of those are necessary, the second pic you labeled everything correctly, the brown you are correct is what they call a junction block there are grounds going there. for the white dash plug basically you need to cut the wires off it one by one and then send them to the correct source.

 

http://forums.hybridz.org/showthread.php?t=115833

 

i can't walk you through wire by wire, but Chris already did, all the info you need is here and here

 

http://www.gweeds.net/carpage2/rb25diagram.jpg

 

http://www.gweeds.net/carpage2/RB25DET_ECR33_Pinout.pdf

 

Pin 104 is AF77 it is an orange wire that goes to the dash plug. the function is unknown, you do not need it connected.

[Pascal]

Then i have situation dear Davide. Cause all wires that goes from ECM(TCM) are conected except 3: pin 5, 14 and 15. All 3 is Signal to Automatic transmission. Peaople claims that is no need to conect. But why then my ECM does not want to give impulse to injectors? i need maybe connect boost control valve or oxygen sensor? Cause they are not conected cause dont have where to conect. And one thing more Davide, his harnes is not same is mine and is not same engine as mine and he have ECM, not ECM(TCM), his ECM is from car with M/T maybe??

 

Best regards Pascal

[Pascal]

I forgot another small thing, from pin 44, on my engine goes wire to dash plug and down to oil pressure bulb. And thoose 2 blue relay, i dont have both, i have onlyeccs relay that connect pin 59,109 49 on power. Other i just connect directly cause i dont have it. hehe But my dearest ECM(TCM) does not work. And again i repeat, if i start to give pulse with my hand, car works perfectly! So all i need is how really works this ECM(TCM). Where is input of signal that ECM(TCM) requesting before to give "GO INJECTORS!!" . Some signal is missing and from 11 wiring diagrams that i have till now i cant get information. And till now 3 "experts" was visiting my workshop, including guy from Nissan, and nothing. I am starting to have fun with that^^. You are closest for sure David!! And i admire you specially if you are not mechanic but doing this of love for cars! More coming as situation goes on. BTW> we even try another ECM(TCM) in case if this one is broken. (witch is imposible, must be broken exactly and only that pin for information that need ECM(TCM) to give pulse to injectors) hehehe one guy did say that if i can find ECM, not ECM(TCM), from Skyline with manual transmision that game is over then, car will work for sure. I dont know and i dont have one at moment altough i did already order one. Mybe Chris Rummel did have that one?? From car with manual transmision ?? MEC-R632R|9908 this one is mine.

 

Best regards Pascal

[Z U L8R]

you have a series 2 rb25det. the only difference is you have internal ignitors built onto each coil pack instead of one ignitor giving signal to all 6 coil packs. you don't have an ignition relay, you have only an ecu relay. you don't have a thick red wire on your dash plug.

 

i am a mechanic by the way lol.

please tell me EVERYTHING that's connected on your dash plug, and what wire you have going to what kind of power or ground source. if you tell me EVERY wire on the plug that you've connected to something, i'll be able to tell you what to do next.