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Rb25 Into R31 Wiring Issues +what Is Plug!?

SKiT_R31

By SKiT_R31,
in General Maintenance

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SKiT_R31 Experienced

SKiT_R31

Posted
Posted (edited)

Hey all, Im having some trouble wiring up an RB25DE (S1 R33) wiring loom into an R31. Its all wired up but it wont fire, the car turns over but just wont fire. Ive checked the timing so its getting spark, theres definitely fuel feeding to the injectors it just wont fire at all, no splutters no nothing, it just lifelessly winds over.

one thing i did notice is when i put the key on ignition, my safc fires up all happy and the ecu has a red light - but when i turn the key and it starts turning over, the light in the ecu goes out and it clicks... is this normal? the safc (2) stays on.

Any idea's of what to check? im stumped...

cheers

EDIT:

The first 3 plugs have no home, what are they for???

the blue relays, im just curious what they are for while im at it

and the white plug up behind the ecu

cheers, im just trying to get an idea of what everything is to help my troubleshooting

ta

post-18637-1168243567.jpg

post-18637-1168243578.jpg

post-18637-1168243597.jpg

post-18637-1168243606.jpg

Edited by SKiT_R31
hobzta Enthusiast

hobzta

Posted
Posted

I had a similar issue in my 180sx...put another sr20det into it and when we tried to start it, it would turn over, and everything but just wouldn't start...sometimes it sounded like it was firing but still wouldn't run, turned out to be that I needed to run the same AFM as the ECU (I had swapped the ecu but not the afm).

SECURITY Grand Master

SECURITY

Posted
Posted

take out a spark plug with the coil pack still on it. have it close to an earth point so it can spark, then take your CAS off and get someone spin it while you hold the spark/coil pack close to an earth point.

firstly, check if your CAS is plugged in properly.

SKiT_R31 Experienced

SKiT_R31

Posted
  • Author
Posted
take out a spark plug with the coil pack still on it. have it close to an earth point so it can spark, then take your CAS off and get someone spin it while you hold the spark/coil pack close to an earth point.

firstly, check if your CAS is plugged in properly.

its getting spark and has perfect fuel pressure, i think for some reason the injectors wont fire... any idea's?

the afm and everything is set up right even if it wasnt it would atleast fire and die in the arse or something - doesnt work without it plugged in also.

What part of the wiring would stop the injectors from firing?

SECURITY Grand Master

SECURITY

Posted
Posted

those two plugs are for your injectors, the one on the top is the one i disconnect when doing compression tests to stop the injectors from firing.

are you sure your fuel pump primes when you turn your reds on? listen out for a humming sound.

post-13452-1168135599.jpg

SKiT_R31 Experienced

SKiT_R31

Posted
  • Author
Posted
those two plugs are for your injectors, the one on the top is the one i disconnect when doing compression tests to stop the injectors from firing.

are you sure your fuel pump primes when you turn your reds on? listen out for a humming sound.

post-13452-1168135599.jpg

mmm both those plugs are in, the fuel pump primes and gives my fpr guage 37PSI

what timing should an RB25 be at? its on 15 degs advanced atm

added pictures to first post what are those plugs for

predator Grand Master

predator

Posted
Posted

bottom plug circled above is knock sensors..

pull off the FPR, and check there is fuel in the rail.

also pull off a plug and see if it's wet with fuel

http://www.skylinesaustralia.com/forums/in...st&id=75720

?? err, you're saying these aren't connected to anything? they need to be wired up to 12v and a few other things in the engine bay.

The relays are very important too, and need to be wired up correctly to fire up the ECU on IGN, and start the engine. They allow the ECU to turn itself off when the IGN is turned off.

I suggest you check the wiring diagrams a bit more closely -- I think you're a bit off the mark from what I can gather from what I'm reading.

SKiT_R31 Experienced

SKiT_R31

Posted
  • Author
Posted
bottom plug circled above is knock sensors..

pull off the FPR, and check there is fuel in the rail.

also pull off a plug and see if it's wet with fuel

http://www.skylinesaustralia.com/forums/in...st&id=75720

?? err, you're saying these aren't connected to anything? they need to be wired up to 12v and a few other things in the engine bay.

The relays are very important too, and need to be wired up correctly to fire up the ECU on IGN, and start the engine. They allow the ECU to turn itself off when the IGN is turned off.

I suggest you check the wiring diagrams a bit more closely -- I think you're a bit off the mark from what I can gather from what I'm reading.

the relays etc are all wired up, they were already modified for an r31, im just trying to figure out what everything is for to aid my troubleshooting

only the plugs in the first 2 pictures arent connected to anything so its them im most concerned about....

predator Grand Master

predator

Posted
Posted

Those first 2 round plugs aren't really plugs.. From what I gather from when I did my conversion they're simply test points for a multimeter or other factory testing.

The second two are either the wiper plugs, or those ones to the body. Maybe they're not needed on an R31 conversion.

colgf Enthusiast

colgf

Posted
Posted

I have 2 possibles- 1- has your car got a car alarm on it??? It could be the anti theft relay not de-energising , 2- Could be the crank angle sensor (on the front of the timing belt cover r/h/s). Did you replace it or bump it when installing engine???? They are very sensitive to voltage spikes or wrong wiring connection (full of transistors that stuff up if not wired up right)..... :P

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