L20Et Wiring

[brandy93]

Hi...i have a problem with my L20et engine...i got the engine from a buddy but the fuel pump relay and EFI relays are missing and don't know where on the ECU the wires for those relays are located...i wanted to know if you can send me a picture or a wiring diagram for this engine please or if you can tell me what pins on the ECU is the wires. Its the original 3 jack type ECU, its also an uncut harness, all the other wires are connected in place straight from the factory from years ago...I could be wrong in asking for this because I don't really know if the ECU controls the fuel pump relay & the E.F.I relay, but i've been looking at L28et diagrams and I saw these relays and thought that since the L20et & L28et are so similar they both should have the same components...but didn't know they had 2 different ECU setups

Another thing I wanted to know is if the L20et works with a high pressure fuel pump because the engine isn't in an R30 Skyline, its in a C32 Laurel which originally came with an L24 Carb engine with a low pressure fuel pump which i swapped out with a RB25DET fuel pump. So I was just wondering if anybody can help me with this tiring situation. Thanks!

[stagefumer11]

yes l20et uses a high pressure fuel pump.

Ecu does control the fuel pump, but actually controlled a Varible controller set under the parcel tray for fuel pump voltage control (noise levels), Isnt the rb25 fuel pump internal ?. Either way if its installed corectly it wont have any problems

For fuel pump power find a iginition source and wire in your own relay with a good power feed from the battery. From what i worked out the l20et ecu doesnt have a rollover protection device that kills the fuel pump, so the only benifit it does is a priming cycle on ignition on. So you will not be missing much.

ECU feeds power to the injectors directly. I know this might not be much help. This is what i fouind when stripping my harness down, I do have a book that covers 90% of the wiring in Jappa's and AUS R30's that ill have a look to see what i can find for you

[brandy93]

Thank you so much for replying mate!..and great advice i would of never thought about connecting it to an ignition..cause i was afraid i blew something lol.

Yea the rb25 is and internal pump...but here's the problem i've been facing...when i connect the fuel directly meaning i just ground it and connect the other end to the battery and start the engine it runs for a minute and cuts off...when i disconnect the pump the car starts and idles and revs but as soon as the rpm comes back down from revving the car cuts off...i have the fuel regulator set at 40psi by the way....when i just connect the pump for 3 seconds to pressurize the rail and start the car its starts and idles for 7 mins without the fuel pump on but as soon as i rev it the car cuts off...but if keep pulsing the wire for the fuel pump on the battery off/on off/on the car works fine...and when i want it to idle i just have to disconnect the pump and when its about to cut off give it the 3 seconds connection. This is when i realized that the fuel pump relay and EFI relays were missing and was controlled by the ECU.

[stagefumer11]

dam thats a intresting one!.

stock pressure with FPR vacume feed disconnected is 36psi.

[brandy93]

ohhh 36psi!! ok ok...so what do you think i should do? by the way are you still getting the wiring for me? even if i don't need it i still want to have it just in case thanks!

[stagefumer11]

Been a bit flat out atm, First time today to jump down and check pc. Ill have a look asap for you

[brandy93]

Thank a lot man! ...ohh I have some pics. of a couple diagrams i have how can I send them to you for you to look at them?