I've finally got my swap all finished up. RB20 into 93 S13 auto. Went fairly well overall, but now it just won't start. Cranks, no attempt to fire. Checked for codes, only 55 (no problem). Fuel pump works. It has fuel at the rail. Pulled CAS and could hear injectors firing when turning it by hand. Unplugged MAF, no different. Sprayed carb cleaner into the intake and she ran just briefly till all the carb cleaner burned up. Ok so it must have spark. So no fuel? I put in an ISIS 255lph fuel pump and a used Nismo Type-A AFPR with the swap. I didn't have a gauge when I installed it, so I was hoping the previous owner had the regulator adjusted in a good spot. Maybe not. Got a hold of a gauge and put it in line before the regulator. Yikes, 85psi (pump on, engine off, vacuum line on). Tried turning it down but wouldn't go any lower than 80psi. For the heck of it, I tried putting the stock FRP back on. Now it's up to 90psi. Checked fuel flow to the rail. Fills up a bottle very quickly. I'm thinking the pressure is just too high for the injectors, either they physically can't open or the fuel blows right by them. But why? Why doesn't the AFPR limit the pressure?
I guess my next step will be to check fuel flow out of the rail to check for possible clog. I didn't have fuel problems with the KA so there shouldn't be a clog in the lines to the tank.
Also might put the stock fuel pump back in just to see what difference that makes.
Now that I've gotten to clear my head a little bit, I'm pondering something. Was I right by putting the fuel pressure gauge in the feed line before the regulator? Or should it be in the return line? I'm used to working on returnless systems, that's why I'm unsure now that I think about it.
Any other ideas/suggestions? This seems really strange, but maybe it's just me. It's been a long couple weeks lately, maybe I just need sleep
06-05-2012, 08:52 PM
Linear Mode
