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Please Help! Rb25det Conversion Problems

smokem31

By smokem31,
in Engines & Forced Induction

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smokem31 Contributor

smokem31

Posted
Posted

Hey people,

i am putting an RB25det into my R31.

OK....

so i have the engine cranking, and fuel pumps working. i have wired everything except for the VVT.

i have two problems. fuel pump doesn't stop priming, and engine wont start.

i have wired as per wiki page, and checked it three times..... i have 12v ignition power at injectors and at plug that goes to coil packs.......

there is no AFM plugged in.

i am still questioning what series engine i have. its def a series 2 loom, but my ECU has a black sticker, so think its a series 1 ECU. no idea what my engine is, i don't know know to tell???

the engine should start with out the AFM and VVT hooked up yeah?

i haven't wired up the neutral switch, but the other plug that need to be wired for an auto to manual conversion has been done.

all this talk of ECCS relay has me really confused.

on my engine loom, i have the ECU plug, the white plug and a 4 pin relay plug. thats it.

i am guessing the 4 pin plug is where the ECCS relay goes?

or am i missing something?

Sorry for all the posts, but this is doing my head in, and i just want my car back on the road!

Any ideas please?

Cheers

wlspn Proficient

wlspn

Posted
Posted
Hey people,

i am putting an RB25det into my R31.

OK....

so i have the engine cranking, and fuel pumps working. i have wired everything except for the VVT.

i have two problems. fuel pump doesn't stop priming, and engine wont start.

i have wired as per wiki page, and checked it three times..... i have 12v ignition power at injectors and at plug that goes to coil packs.......

there is no AFM plugged in.

i am still questioning what series engine i have. its def a series 2 loom, but my ECU has a black sticker, so think its a series 1 ECU. no idea what my engine is, i don't know know to tell???

On the coil cover (over the coilpacks) do you have a black-box towards the back? If so this is an ignitor & you have a 94' engine. If not, you have either not wired it in or have a 95' - 97' engine. If still unsure post close-up pics of coilpacks. Or someone probably has an easier way to tell... I'm half asleep!

the engine should start with out the AFM and VVT hooked up yeah?

Yes, neither of these is necessary for the car to start. Without the AFM you will be in fail-safe & without VVT you will have no mid-range but will still run

i haven't wired up the neutral switch, but the other plug that need to be wired for an auto to manual conversion has been done.

Do you mean the auto trans park/neutral switch (inhibitor switch)? If so & you are running an auto ECU, the car wont start without that.

Also if you mean the manual trans neutral switch but are still running auto ECU the same will probably apply. Inhibitor switch will stop car from starting. Someone had a similar problem a while ago...

all this talk of ECCS relay has me really confused.

on my engine loom, i have the ECU plug, the white plug and a 4 pin relay plug. thats it.

i am guessing the 4 pin plug is where the ECCS relay goes?

If the relay fits into the "4-pin plug" & is next to the ECU plug, then I would be saying yes. A possible cause for your fuel pump priming non-stop (maybe...) Either that or directly earthed instead of through ECU? If you don't get any definite answers tonight post up pics of what you are unsure about...

or am i missing something?

Sorry for all the posts, but this is doing my head in, and i just want my car back on the road!

Any ideas please?

Cheers

Let us know how you go, post pics if need be & we'll go from there. Good luck!

smokem31 Contributor

smokem31

Posted
  • Author
Posted

i am not running an igniter cos there is no where to plug it into the loom. its def a series 2 loom, but i dont know its its series 1 or 2 coil packs.....

the fuel pump did prime properly when i first wired it up. it turned on for about 5 secs, then off again. but now, for an unknown reason, it stays on....... is it a problem if its always priming?

i dont know if its an auto or manual ECU.... are they different?

the car cranks, and sounds like it wants to start! haha, i have had a problem with inhibitor switch before, and car didnt even attempt to crank.....

the fuel pump is directly earthed..... well, wire 50, which is earth on ECU, is directly earthed to body, and is same earth as fuel pump relay......

thanks guys

wlspn Proficient

wlspn

Posted
Posted

Would have to be (or would bloody hope...) you have series 2 coilpacks as these have the ignitor built in. So running a series 2 loom with series 1 coilpacks would not work... Did you buy the complete engine (including coilpacks, etc), loom & ECU as a package, all off the same car?

Only thing I can think of with fuel pump is a bad earth.

You are right, if inhibitor switch was the problem, it would not even crank... Wasn't paying full attention to your original post.

& come to think of it, not sure if manual & auto ECUs are different or if R33s all run same ECU & have a seperate auto-trans ECU like the RB20 R32 does.

blind_elk Grand Master

blind_elk

Posted
Posted

Ok, it's fine that you have power to coils and injectors, but do the coils actually fire, and do the injectors actually inject?

And do you have the fuel lines on the right way round?

smokem31 Contributor

smokem31

Posted
  • Author
Posted

i was thinking about the fuel lines this morning... the regulator connects to the fuel tank return line yeah?

is the best way to test if injectors are injecting with noid lights?

the loom does belong to this engine, but i got it all in pieces..... so according to loom, its a series 2 engine, but its a series 1 ECU.....

thanks

blind_elk Grand Master

blind_elk

Posted
Posted
i was thinking about the fuel lines this morning... the regulator connects to the fuel tank return line yeah?
Yes.
is the best way to test if injectors are injecting with noid lights?
Couple of ways. Yes, use a noid light. Or use a stethoscope to listen to the injectors while the engine is cranking - you should hear them tick...tick...tick. Or remove an injector, stick it in a jar, loom connected, and watch it spray fuel as the engine cranks over.
Don Dada Mentor

Don Dada

Posted
Posted

Series 1 coils would not plug into a series 2 loom and vice versa.....so once they plug into each other u have matching coils and loom.

The difference is the ignitor is built into the coil pack on the series 2 whereas there is an external ignitor for the series one.....the ecu is the SAME

Hence the reason series 1 and 2 use the same pfc with no options to set between engines

BH_SLO32 Proficient

BH_SLO32

Posted
Posted (edited)
Hey people,

i am putting an RB25det into my R31.

OK....

so i have the engine cranking, and fuel pumps working. i have wired everything except for the VVT.

i have two problems. fuel pump doesn't stop priming, and engine wont start.

i have wired as per wiki page, and checked it three times..... i have 12v ignition power at injectors and at plug that goes to coil packs.......

there is no AFM plugged in.

i am still questioning what series engine i have. its def a series 2 loom, but my ECU has a black sticker, so think its a series 1 ECU. no idea what my engine is, i don't know know to tell???

the engine should start with out the AFM and VVT hooked up yeah?

i haven't wired up the neutral switch, but the other plug that need to be wired for an auto to manual conversion has been done.

all this talk of ECCS relay has me really confused.

on my engine loom, i have the ECU plug, the white plug and a 4 pin relay plug. thats it.

i am guessing the 4 pin plug is where the ECCS relay goes?

or am i missing something?

Sorry for all the posts, but this is doing my head in, and i just want my car back on the road!

Any ideas please?

Cheers

You need the ECCS relay which plugs into the 4 pin plug you mentioned. This feeds power to the CAS, AFM and some pins on the ECU. Without this you won't be going anywhere!

The fuel pump relay sounds like it is connected directly to earth (on the coil/trigger side). Consequently when the relay sees power it will switch on and stay on. The relay should be controlled via pin 18 on the ECU. It is the trigger/coil side of the replay that needs to be connected to pin 18. Assuming you use the same type of relay as the ECCS relay, the configuration should be 12V feed to pins 1 and 3 (ie connect the existing R31 fuel pump wire (white from memory)), pin 2 connected to pin 18 and pin 5 connected to earth. Pins 1 and 2 are the coil/trigger side and pins 3 and 5 are the switch side of th coil.

Hope this helps.

Edited by BH_SLO32
smokem31 Contributor

smokem31

Posted
  • Author
Posted

the fuel pump relay is connected to ECU pin 18 as the input trigger. but is earthed directly to body. rather than earthed through ECU. would that matter?

i have plugged a normal realy into the ECCS plug.

how does this ECCS relay get power? through that white plug on the engine loom?

femno Grand Master

femno

Posted
Posted
the fuel pump relay is connected to ECU pin 18 as the input trigger. but is earthed directly to body. rather than earthed through ECU. would that matter?

i have plugged a normal realy into the ECCS plug.

how does this ECCS relay get power? through that white plug on the engine loom?

I think you should remove that earth, and just let the ECU control it like it should.

Also, you should only plug the correct nissan relay into the socket with corresponding colour, otherwise it may not be doing what it should. Then you can eliminate the relay as a problem.

...And put the injector in a container with the loom connected?????? What about fuel pressure! lol Yeah dont try that one.

smokem31 Contributor

smokem31

Posted
  • Author
Posted

thanks for all the help guys. i cut the extra earth wire running to the ECU ground, and fuel pump primed perfectly, and car started!

happy as larry........

so, thanks again......

was blowing a heap of smoke though. looked blue/grey, but smelt like running rich..... straight out of dump though, no exhaust connect as yet.....

now just have to wire vvt, and run exhaust and cooler piping.

blind_elk Grand Master

blind_elk

Posted
Posted
...And put the injector in a container with the loom connected?????? What about fuel pressure! lol Yeah dont try that one.
Nothing wrong with it. The injector holds the fuel pressure. And it only opens for a few milliseconds each revolution during "start".
ltcree Contributor

ltcree

Posted
Posted
there is a control unit that is under the intake plenum, that has the heater hoses running to it as well.... what is meant to plug into this unit? i cant find the corresponding plug on the engine loom.....

I think its either a purple or brown (2pin?) plug, cant remeber off the top of my head. It'll be running rich because you dont have you AFM connected, probably wont rev very well either.

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