Help me get this thing started!

Discuss the RB20, RB25 and RB26 series engines.
RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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hi everyone. I know what you're thinking...."another freakin start my engine for me thread?!?!"

but that's what its come to. I'm stumped. Engine is an RB25DET (series 2). I've been trying unsuccessfully to get it started. There are a couple things you should know first off.

1. Intercooler piping isnt complete yet (so i stuck the MAF directly onto the intake pipe...effectively bypassing the turbo system)

2. I'm still waiting on a new AAC valve. (so nothing is connected to AAC port)

Would either one of these things prevent the engine from starting? I'm just trying to get it to idle to make sure my wiring is right and to give me some more motivation to finish my piping and the misc stuff that still needs to be done

I'm pretty sure i've got all my wiring correct. I used the guides from Racebread, but mostly just ECU pinouts from my old engine and the new one, matching up all functions.

I'm currently not getting fuel OR spark. Fuel relay/pump seems to be fine since it fires up when i turn the key to ON, and also it starts right up when i turn my CAS by hand. This would lead me to believe that the ECU is getting power...correct? After cranking for a while, i pulled a plug and it's dry as a bone. Then i hooked up the ignitor to the plug so i could see the electrode....grounded the plug, turned the CAS...and nothing!

Anyone have any suggestions on where i should start? I find it odd that i'm at least not getting fuel since the pump seems to work, and the ECU has power.


RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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got my AAC valve, plugged it in, same thing. any ideas?

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matafied
Posts: 423
Joined: Mon Jan 08, 2007 8:15 am
Car: 1989 240 rb25det 1992 240 rb25det

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yea neither one of those things would keep it from starting up, you def have a wiring problem, sice your fuel pump is coming on you seem to have that strait. double check the main points with this zerothread?id=18442

i would check to make sure you have the gray wire on your rb white plug connected to the black/ red if i remember correctly in step four, i think it is your injector power.

also what starts when you turn your cas by hand???

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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thanks for the advice....that step confuses me a little, and i think that might be where i went wrong....i don't remember splitting it two ways (one to ecu, the other to the dash plug???) I'll take a look at it. thanks again!

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matafied
Posts: 423
Joined: Mon Jan 08, 2007 8:15 am
Car: 1989 240 rb25det 1992 240 rb25det

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no it dosent go to the ecu, basicaly on the white plug ( skyline ) you connect the gray and black\red, then you find the black\red wire from s13 and connect it with them. soldier heat shrink . so they all connect together ( 3 wires-- gray, black\red skyline, black\red s13)

craz4240
Posts: 738
Joined: Wed Sep 13, 2006 4:23 pm
Car: 1995 240sx w/rb20det
Contact:

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Definatley wiring your car will start withoput the mafs plugged in..hell the one in my yard started without the top of the intake plenum on hahaha.

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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according to opensource's guide:

"step four: back under the hood, find this plug (the plug is down hear the fuse box and it will have the same wire color setup. oh for those who are wondering, we cut all these plugs from the KA efi harness to plug into the KA engine harness so we wouldn't have any direct wires, we can still disconnect everything.

from that plug find the black/red and red wires and mate them with the black/red and red wires from the white efi plug and mate the grey wire from the other rb efi plug (see pic) into the black/red from the white efi plug (basicly the black red will be split two ways, one into the efi plug and the grey into the other efi plug, see pic). the red just goes to the white efi plug (as i mentioned earlier)."

:....

i can't find this gray wire anywhere on my diagrams. although i recall seeing a gray wire that wasn't connected to anything when i was checking some of my wiring. the gray wire is part of the skyline harness, in the engine bay, correct??

It leads to the plug that i cut off in order to solder to the brown & gray body plugs, right?

but.....will this wire solve my fuel and spark problems? It seems like this is just an ignition wire...

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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could you possibly mean the gray/red wire?? I can't find anything that's gray on the pinouts...although there is one i found in the engine bay.....but its too late to trace where it goes since i loomed everything up. check out the diagram below...gray/red called [ignition switch (start signal)]

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BoostFab
Posts: 3529
Joined: Wed Dec 03, 2003 8:23 am
Car: S13cp, S13fb, S14z
Location: Nismo Land
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this is out of the air, but did you check if your fuel line is connected correctly ?

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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yep...at least i believe so

the FPR goes into the return line....

and the line from the filter goes into the fuel rail directly...

correct?

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

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nevermind about the gray/red...i remember i connected that to the KA orange wire (start signal)

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mello88
Posts: 611
Joined: Tue Jul 27, 2004 6:37 am
Car: s13

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NO fuel + NO spark = no signal from CAS

Please elaborate on it "starting" when you turn the CAS by hand? IF that is the case... It sounds like your CAS isn't being engaged by the camshaft if that's the case.

Go back to the basic... When you spin the CAS by hand, does each ignitor pack fire? Does each injector fire? If yes then your wiring is fine. It's an issue with timing or a mechanical issue with the cas/cam.


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matafied
Posts: 423
Joined: Mon Jan 08, 2007 8:15 am
Car: 1989 240 rb25det 1992 240 rb25det

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matafied wrote:
also what starts when you turn your cas by hand???
????

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

Post

it was the gray wire

It runs like a beast now...let it idle for like 5 min while filling up the radiator. Still haven't hooked up my fans, but i should be able to drive it by next week!!!!

thanks for all the help fellas

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matafied
Posts: 423
Joined: Mon Jan 08, 2007 8:15 am
Car: 1989 240 rb25det 1992 240 rb25det

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RBSilvia wrote:it was the gray wire
sweeeeeet

RBSilvia
Posts: 88
Joined: Sun Dec 16, 2007 6:31 pm
Car: '89 RB25 S13 Coupe
'91 SR20 S13 Coupe

Post

out of curiosity....what is the function of that gray wire, and where does it go since it doesn't go to the ECU?? a relay or somethin? how was i supposed to find it if it's not on the ecu pinout?

reason i ask is because i'm about to help a friend with wiring on an RB25 NEO, and want to know more about the problems i had with mine

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matafied
Posts: 423
Joined: Mon Jan 08, 2007 8:15 am
Car: 1989 240 rb25det 1992 240 rb25det

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its injector power source B+, ecu dose not supply injectors with the B+ thats why its not on a ecu pin out. you wont find everthing you need on an ecu pin out


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