quick question bout fuel pressure .....

[preston240sx]

UPDATEok so when doing my swap i have'nt put my new 255lhp fuel pump in and my rb wont run like im not getting enough fuel to the rail ? when a starting fluid is introduced she fires right up .... i might have the lines crossed not sure i i have the line from the fuel filter going to the fpr/fuel rail and the other going from the fuel rail to the return line .. right or not ?also could the gas in this car be bad and would that cause it not start ? i figured it would just like **** ?

so what i asking is can u use the stock fuel pump or is it not strong enough?

would the gas cause it to not start ?

and did my i put my fuel lines backwards ?

thx
Modified by preston240sx at 6:32 PM 1/1/2008

[rb25drag]

Fuel lines are backwards the return line hooks to the FPR!

Stock pump should be fine to fire the motor and keep it running.

[preston240sx]

thx i'll reverse them and hopefully she'll fire up then

[driftingmy240sx]

when i first got my rb25 runnig it drove it for a month on the stock 240 fuel pump with no problems.

yes your fuel lines are backwards. fix that and as long as you dont have any other little mistakes it should run for you.

[mello88]

Like they said your lines are backwards. The fuel pressure regulator is the last thing the fuel goes thru before returning to the tank. Also the KA fuel pump doesn't supply enough fuel to run your engine safely, you should upgrade to Walbro or Bosch or Supra pump ASAP.

rb25drag or driftingmy240sx, did you guys have wideband o2 installed while you were running KA pump? I doubt you'd spend money on wideband instead of Walbro... But curious if you looked at AFRs during this time.

[preston240sx]

yeah i got the pump just never put it in yet probley do it today so i'll let you guys know tonight thx

[mello88]

install is really fast, should only take you 15 or so.. GL

Do you have a Nismo FPR? I ask cause most of our stock RB FPRs are shot, usually combined with the Walbro/Bosch/Supra pump you'll end up running rich.

[BoostFab]

check the line, and report back!

[preston240sx]

ok installed works louder then the stock one lol still no fire ..... checked all the coil pack and spark plugs for spark and they checked out i can hear fuel going and can feel the fuel going back on the return i have power to my ecu and everytime i turn the CAS by hand the fuel pump kicks in and i hear nothing but the coil packs ..so whats wrong with my fuel injectors....?

[mello88]

probably nothing is wrong with your injectors, your fuel lines were swapped did you fix that already? do you have a fuel pressure gauge? crank it for a bit then pull the plugs you should smell fuel on all of them. Your timing is probably off? Otherwise test the injector leads and make sure you're getting +12v on all of them, and occasional grounding from the ECU as you rotate the CAS by hand.

[preston240sx]

yeah i swapped the lines ....pressure gauge is on order from summit .. timing should be fine still have the stock belt ..and the CAS still had the seal tape on it before i pulled it off my plugs are all dry no gas smell it going through the fuel rail ... circulating .....guess next step is test the injector leads .... if they dont pick up 12v what would the problem be ?

[craz4240]

Pick up or borrow a set of noid lights to check the injectors for firing

Your car should start with very minimal stuff hooked up.

[preston240sx]

yeah i have min stuff hooked up i have everything hooked up that has a plug that came on the harness i had done at the shop out here in SD do you have any idea where i can find the noid lights that would fit a nissan or are they a pretty universal ?

[driftingmy240sx]

no mello88 i did n ot have an afr hooked up. it did however amazingly though run rich. i also now have a walbro and fpr on it.

[rb25drag]

Like they said your lines are backwards. The fuel pressure regulator is the last thing the fuel goes thru before returning to the tank. Also the KA fuel pump doesn't supply enough fuel to run your engine safely, you should upgrade to Walbro or Bosch or Supra pump ASAP.

rb25drag or driftingmy240sx, did you guys have wideband o2 installed while you were running KA pump? I doubt you'd spend money on wideband instead of Walbro... But curious if you looked at AFRs during this time.

I had my Walbro pump installed before I ever owned the engine LOL!!!

I just installed my wideband a few months ago!!

[preston240sx]

um ok

[BoostFab]

any sign of fuel on the plugs ? is the fuel line in the correct flow direction?you have an rb20 right?

[preston240sx]

i can get it too fire and run only if i pour gas in the intake .. yes i have everything hooked right on the fuel side .. and no sign of fuel on the plugs ...yes it a rb20det

[BoostFab]

i can get it too fire and run only if i pour gas in the intake .. yes i have everything hooked right on the fuel side .. and no sign of fuel on the plugs ...yes it a rb20det

if your lines are connected correctly (fpr to return line) ; then it's obviously there's no power going to the injector; check the wiring on the gray oval plug, it might not have wired in correctly. who did your wiring?

[preston240sx]

Nick from Neo-Tech Imports in Santee (San Diego area)

[mott6904]

If your fuel pressure is good and the lines are in the correct position i would check for power and groung at the injectors. Either use a noid light or a multimeter. Without looking at a diagram your injectors and other sensors get power through the eccs realy. If you dont have power then i would check that realy to see if it has two wires that have 12 volts and a switching ground whenever you turn the key on. if so then its the relay if not fix the wire that is not getting power or a ground .

[preston240sx]

so you mean check the 2 relays that are down by my ecu .... I'll get on that first thing in the morning before the football starts i'll check all my main power points if the relay is bad that would def explain the problem thx

[apollas]

Nick from Neo-Tech Imports in Santee (San Diego area)

Nick is the **** for socal wiring

I got my motor from neotech also and wiring from spencer and nick. their motor and wiring jobs are reputable. that **** just fired up for me when they finished my wiring. is your maf disconnected? try unplugging the maf and crank your car while feeding it some throttle

[preston240sx]

yeah i unplugged the maf i think its a bad relays cuz i believe there's no power going to the injector harness ... but i have'nt gotten to check yet so i'll keep it posted when i do thx

[BoostFab]

this is simple, but did you have a grood ground to the motor

[preston240sx]

im pretty sure i have a good ground but i could be wrong

[mott6904]

Plug the maf back in and then try it. If the maf is unpluged it will only try to start and die right away. It sounds like you have the right relay. Mine only has one relay so i dont know what kinda of setup you have or who did your wiring. If he removed the injector harness and he doesnt have power then i dont see how bad engine ground could cause this but i would recomended having a couple of engine grounds around the starter, coil pack and a couple on the intake mani. The only ground that would cause no power at the injector harness would be the one from the computer that turns the relay on.

[preston240sx]

thx ima go out to the garage today and try and check the power to both relays i'll even get you a pic of the wiring so you can see what going down ... thx i'll keep updated

[preston240sx]

ok so i took some voltage readings and the injectors are get 0.86 volts my mulitimeter only reads volts ... and i Checked the relay plugs by my ecu and here's what they came out to

plugs 1 Orange-12vwhite/blk-12vwhite/blk-12vblack/white-ground

plug 2 orange-12vwhite/black-groungwhite-12vwhite/purple-0v

so is that where my problem is ? my other relay is'nt get the right power to work ?

[mott6904]

First off what engine and series are you working with. From what i can remember from doing my wiring plug one looks like your eccs relay. From the readings you took the relay is working. As for plug 2 i dont know what that goes to, but from the readings you took the relay doesnt appear to be working. I dont have that relay in my r32 rb20, so i dont know if it is used or not, but plug another relay in plug 2 and see if it runs. When you tested the injector harness for voltage did you prode one lead to a body ground and the other lead to one of the wires? The injector has power at all times and the computer using a ground signal to open it up. You might want to get a ecu pinout and check all of your power and grounds that the ecu is supposed to have. If you dont have a pinout you can get a a pdf service manual from http://skylineking.com/info.html to help you out more. I really need to know what series rb20 you have before i can really help you. Im assume your plug 2 relay is bad and it is a major power feed to the injectors but i dont have the car to give you a definate answer. A lot of info but hope this helps.