Running lean and missing down low. AFPR? Pump? - Miata Turbo Forum - Turbo Kitten is watching you test compression.

_spyder · **Running lean and missing down low. AFPR? Pump?**

I finally got my fuel pressure gauge on the correct line and am able to read pressure under the hood.

I've got a BEGI AFPR with 305cc green top injectors and supposedly a Walbro fuel pump. We tried blowing compressed air down the fuel line to send it back into the gas tank after we unhooked the lines. It seemed clogged or something, not sure if it's the AFPR or what, but it wouldn't seal and only blow a little gas or air back out at us, not allowing the nozzle to seal in the hose.

I'm seeing ~80psi at idle. When I rev it from under the hood, the fuel pressure drops a bit. When I'm in boost, the AFRs no longer stay put, they drop down and then start to rise (lean) as I stay WOT in full boost (10psi). It also runs stupid lean (---) on my Wideband until I get up higher in the RPMs.

My friend who is heavily into 240's says that the idle pressure seems really high at idle and I think that it isn't supossed to dip when I give it throttle. Thoughts? What's my problem here?

I want to diagnose this. Could I safely take the AFPR out and turn down the boost without touching anything else to test if that's clogged/old? Any way to test the pump if it's not the AFPR? Or maybe it's the injectors...

I will eventually Squirt it with 550's but I want to get this figured out first.

Help me, I'll try to get a video up soon. Gimme some things to do/check here people, I'm desperate.

Cheers.

mc85 · 05-29-2012, 01:21 AM

Idle pressure seems high, but could be the walbro pump..? My sig needs updating but I have a jrsc with afpr and see maybe half that at idle.

Could be a stupid question, but have you replaced your fuel filter?