Thread: PS13 cranks but won't start

Hello! My bf has a 1991 ps13 and we are having starting issues. He swapped in another SR20DET with a Link G4+ ECU from a 180sx, also a Walbro 255 fuel pump at the same time. It will crank and crank and crank and won't start. The fuel pump will prime but it won't shut off. We think the ECU is not receiving enough power somehow, or the fuel pump is drawing too much power, because the LED light on the ECU will also not come on, we also tested the power pins leading into the ECU:

- Pin 38 (ECCS RELAY - main power) shows Voltage of 3.5, which then drops to 2.5 when the car is turned over.
- Pin 104 (Fuel pump relay) shows Voltage of 4.2 then drops slightly when the car is turned over.
- We also tested power to the plug directly along the wiring from the ECU (brown plug). This plug receives 12.4V.

Now for the weird bit.. we swapped in the OEM ecu and installed the MAF (on the Link ecu the maf is mapped out), because why not just to see if it starts.. led comes on, fuel pump primes and shuts off after a few seconds, car then starts straight away, runs, then started to get a little rough after a few minutes then it cut out.

The same pin tests were done using the OEM ecu, and both pin 38 and 104 received 12.4V

We tried supplying direct power to the Link ECU from the battery, and the car started up and ran straight away, so we know the ECU does work and will run the car, but it won't under it's own power. We are a bit stumped on what else we can do now!

If anyone has any help we'd be eternally grateful as it's been sat now for 2 years :')

if i recall correctly s13's have an issue with a fusible link, its in a box in the engine bay drivers fender by the battery i believe.. some googling may point you in the right direction.

Oh boy, that's a tough one. I can only imagine something strange is going on with the ECU, or whatever controls the power to the ECCS relay. The only advice I have is to continue to narrow things down and rule out causes. Get closer to the source of the problem. It's just been so long since I messed with the wiring harness and ECU stuff I just won't be of much help.

That fusible link I mentioned ties to the eccs relay