Anyone using a chipped RB20 ecu to control RB25?

[autocrossing]

I picked up a chipped RB20 ecu to control my S1 RB25. I had a stock 25 map burned to the chip. When I plugged it up the fuel pump clicks on for a second and the car cranks but doesn't fire. Doesn't spit or anything. I also have a chip with a stock rb20 map and it does the same thing, which is nothing. So before I assume the ECU is bad and buy another rb20 ecu to chip, I'd like to double check that it is possible to use a 20 ecu for a 25.

Thanks,Marshall

[Coolwhip]

Yea, had a buddy fire his up on a chipped RB20 ECU on his RB25 S1. No problems besides his motor ended up being fubar on piston 5.

[craz4240]

I'm not 100% sure but don't you have to repin a few terminals to get it to work?

[lyon23]

yes you have to repin or move a couple of the coil wires not sure wich ones (maybe 2 and 5) look at both ecu pinouts to see the diference. When I programed my ecu i noticed some things, check it when you turn the ignition on if you hear the pump for just like a fraction of a second I think it didn't load the map, it should stay on and sound for 2 seconds or more if that doesn't happen check the light on the ecu and see if it's blinking that also means it did not load the map. you should have a steady non blinking light if it's alright. When the map did not load the light blinked steady (no fault code) on mine and the car turned on but it had too much fuel it would not rev and finally it turned off and didn't turn on again. Hope that helps.

[autocrossing]

Thanks lyon, that was the issue, the maps appearently hadn't loaded to the 2 chips I tried. I popped in the third one and the car fired up. So in case anyone searches this in future, I'm using an automatic R32 RB20DET ecu to control a manual R33 S1 RB25DET. No pins were switched, just plugs in.

Thanks for the replies,Marshall

[midnightsliding]

im looking at doign the same thing but with a RB25 SII

[Carl H]

if you want it to run right you'll need to swap injector triggers for cylinders 4 and 6.

[Kansei240sx]

I am going to do the same as well.

Use a Nistune ECU chip on an RB20 ecu. Ill see how it works out.

[Yellow4g63]

I am going to do the same as well.

Use a Nistune ECU chip on an RB20 ecu. Ill see how it works out.

I'm ordering up that board soon for my RB20 ecu too. Can't wait!

[autocrossing]

if you want it to run right you'll need to swap injector triggers for cylinders 4 and 6.

Is that for S2 only? My S1 seems to run perfectly.

[meet07]

how does the rb20 ecu read the high impedence injectors? so u dont have to swicth over to low impedence injectors with a resistor box?? seems a lil weird.

[Cjmartz2k]

RB20's use high impedence injectors just like RB25's.

[SullivanRacing06]

both high impedance in 20 n the 25

[meet07]

then what is function of the resistor pack that is needed if you use r34 injectors?