RB25det swapped into s13...Has issues

General discussion forum about the 240sx, and a great place to introduce yourself to the board!
slidingsideways13
Posts: 6
Joined: Sun Mar 15, 2009 3:49 pm
Car: fully built sr20 s13

Post

Rb25det into s13 now won’t start.

Long story short I pulled my running Rb25 out of my hatch and swapped everything over into a coupe. Now it won’t run.

Fuel pump is hardwired to battery via switch/ relay system and with the fuel pump on the engine tries to start but won’t catch. Turn off fuel pump and the engine actually starts and runs until it fully burns any remaining fuel. Turn pump back on and it won’t fire. Has basically new DW 1000cc injectors on a tuned RS Enthalpy z32 Ecu. Thinking the Ecu is shot somehow and no longer controlling fuel correctly, red led on Ecu is constantly lit and will not switch to diag mode. If it idles with fuel pump switched off and I switch pump on it will instantly stall.

Aftermarket FPR shows 43psi. Fuel lines are hooked up correctly. Injectors pulled and tested for leaks and passed. Grounds all hooked up. Z32 maf checked and swapped with known good unit. Timing wasn’t touched from running in the hatch to swapped in the coupe. No vacuum leaks when it idles for a few seconds vac gauge reads near 20. New ngks gapped correctly.

Thoughts?


User avatar
NukeKS14
Posts: 310
Joined: Wed Apr 10, 2019 2:50 pm
Car: 1995 240SX SE - KA24DE-T
AC Cobra Mk IV Rep.
2020 Civic Si

Post

slidingsideways13 wrote:
Sat Aug 15, 2020 1:08 am
Fuel pump is hardwired to battery via switch/ relay system and with the fuel pump on the engine tries to start but won’t catch. Turn off fuel pump and the engine actually starts and runs until it fully burns any remaining fuel. Turn pump back on and it won’t fire. Has basically new DW 1000cc injectors on a tuned RS Enthalpy z32 Ecu. Thinking the Ecu is shot somehow and no longer controlling fuel correctly, red led on Ecu is constantly lit and will not switch to diag mode. If it idles with fuel pump switched off and I switch pump on it will instantly stall.
I'd be focusing on this. So you hardwired the fuel pump, what did you do to the wires from the chassis? How is it hardwired, exactly? It almost sounds like you're backfeeding 12v through the chassis harness to the ECU (maybe through ground even?) This specifically seems like it's related to your problem if it isn't the issue itself.


That's weird about the red light on the ECU as well. Have you reached out to Martin @ Enthalpy regarding that? They're incredibly supportive of their products and Martin is very helpful.

Cgeigert
Posts: 225
Joined: Sun Oct 08, 2006 7:43 am
Car: 1989 Nissan 240sx

Post

Definitely check out ECU but random possibility is that with fuel pump on it floods the cylinders, and with it off it burns off the fuel in the line.

User avatar
PapaSmurf2k3
Site Admin
Posts: 23998
Joined: Thu Nov 21, 2002 3:20 pm
Car: 2017 Corvette, 2018 Focus ST, 1993 240sx truck KA Turbo.
Location: Merrimack, NH

Post

Yeah, try dropping the fuel pressure to 30 or so psi and see what happens.


Return to “240sx General Discussion”