View Full Version : rb25det starting issue help drives fine and accelerates hard start

07-14-2013, 04:45 PM
ok guys before you start yelling at me lol i have done a lot of research and whatever problem i have found was left unanswered so lets begin i have a 95 240sx it has a rb25det series 2 i believe stock engine as far as i can tell mods would include ebay front mount some aftermarket bov apexi afc neo electronic boost controller full 3 inch exhaust and i think thats about it so now to the problem when i turn the key the fuel pump stays on so when i crank it just turns and turns and i can smell some gas the fuel lines have around 40 psi so i know im getting fuel i put a switch on the fuel pump so when i turn the fuel pump on for a split second and try firing it over i will start to fire up of course foot planted to the ground on gas pedal and i have to keep turning the fuel pump on and off and finally it barely fires up the car drives and accelerates fine i already checked the temperature sensor and when i unplug the rpms change so im guessing its working idk im stumped you guys oh and the wiring is pretty messy but im sure thats probably half the problem but is there anything else before i order a new wiring harness?

07-15-2013, 12:40 AM
Have you opened the ecu and checked the capacitors?

07-15-2013, 01:30 AM

07-15-2013, 11:26 AM
lmao thats funny well your right i am a noob in this area but hey 1jzsilcoupe thanks for the advice im gonna check it out and come back and give you guys a update but as far as feito is that wire your talking about have a specific color or the location of the pin on the ecu?

07-15-2013, 12:10 PM
also the car fires up a lot faster when its warmed up but on a cold start sometimes takes forever. i can hear a combustion for a second and then a few turns later another and so on until it stumbles its way for a couple seconds to a really slow fire up. no known issue of accelerating wot no misfires or anything but it seems to lose a little power around 6.5k and up. leaky O ring on the injectors? i put silicone on the coil packs gained more power but that was sometime ago never fixed the problem with start up oh and when you roll the car and jump start it, it fires up right away idk if that helps

07-15-2013, 10:42 PM
ok here u go man, i had a very similar problem when i first swapped my 25 and it was a pain, so hopefully i can help you...
pin 43 at the rb25 ecu is for a start signal, from there it goes to f3 pin 34 with a splice or solder in between. Then from there to a 7.5 amp fuse called starter signal under your dashboard, then finally to your ignition switch, i think lol, here's a little something for you

ka24e-t no start, weird ST SIGNAL problem : KA24ET / KA24DET Forum (http://forums.nicoclub.com/ka24e-t-t573906.html)





07-18-2013, 04:11 PM
Awesome thanks ill dig around grr when it comes to mechanicals I'm fine as soon as a wire or electrical problem happens I have no idea what I'm doing so shoot how do I do this can you explain how to read the wiring in a little more detail if its not too much to ask for?

07-18-2013, 04:31 PM
I looked at my ecu and there is a spaghetti bowl of wires and lots of electric tape and I disconnected the apexi afc and the car didnt want to fire up I'm guessing new wire harness? Oh and on hot days car starts over heating even after I pulled the thermostat out