R32- RB20DET won’t idle

[Disturbed32]

Hey all, I’ve tried searching forums and can’t find exactly what’s happening to me so I thought I’d make a new post, forgive me if this is the wrong area, but I do need an opinion.

I’ll start by setting up the picture, so I bought an NA r32 about 5 years ago, it IS factory RB20DET however the previous owner had an expensive set up previously I believe so he removed the turbo parts including manifold turbo etc etc and put NA parts on the turbo motor, so just straight headers and some chunky welded exhaust with an NA computer and HORRIBLE wiring harness (chopped and spliced everywhere).

So about 2 weeks ago I had enough of not being able to keep up with literally anything as it would run horribly, and converted it to turbo, I just finished it today, I used some parts from the various RB25det’s and parts I have laying around since I’ve had a couple skylines, so I’ve changed the following

-RB25DET turbo - New lines - RB20det ECU (second hand) - new wiring harness - front mount intercooler - I fabricated my own intercooler piping (no leaks) - rb25 AFM ( I have the original 20 AFM as well) - new radiator and new exhaust system and dump pipe. 
 

After putting it all together today, it won’t idle, now it could be because I’m super tired and been welding and just can’t think properly and I may be missing something but I need an opinion, if I unplug the AFM it’ll run, but idle at around 2000RPM and just sit there and if I go to rev it, it’ll just bog down, if I unplug the TPS (with AFM plugged in) it’ll start run on 1000 for 2 seconds and then die slowly and turn off. 
 

If you guys need any more info just ask, I have some ideas but I’d like to see what you RB experts have to think about it. 

Any help will be appreciated. 

[GTSBoy]

RB25DET ECU is the wrong choice. There are sooooooo many differences.

Use the 20 ECU. And the 20 AFM.

[gillies2001]

I think you misread, He is using an RB20 ECU

[Disturbed32]

Yeah using the 20det ecu and according to a forum thread I read the 20det and s1 25det AFM is the same 

[GTSBoy]

Oh, I did misread.

Either the AFM wiring is not right, or the idle control wiring (or the IACV) is not right.

Or, the million other random things it could be a car that has been hacked apart and then hacked back together. Seriously, just one wrong wire somewhere could cause all this.

[TurboTapin]

The S1 RB25DET MAF is the same as an RB20 but I don't believe the S2 is, I may be wrong though. Confirm which one you have. 

[Disturbed32]

All fixed guys, so I had a spare set of injectors from another rb20 and put a walbro 460 in with a TS FPR1200 and set the fuel pressure and it runs completely fine now :) just wasn’t getting enough fuel it seems, my bad.

thanks guys