machine4321

Well i will get this out of the way. I have built a fun daily driver d16z6 with boost.
With the stock exhaust on i can tune the car through the rev range (yes it is terribly slow)

With open down pipe cant stop it from leaning out after 5000rpm. My aftermarket pump will not be here for another 2 weeks. I really though the stocker would support at least 160hp (i really cant see this car making anymore then that it cant even break the tires loose in 1st lol)

Hooked up a fuel pressure gauge and at idle it sits at 30psi....to low right? pull the vac hose and it goes up to 40psi. Heres the wierd part. i can pinch off the return line completly, and psi goes up to 80, and the car doesnt even hicup or anything. there is no change in the idle at all.

I tested the voltage at idle and it was about 13.5(at the pump) . could be a bit higher but still should work for under 200whp.

The fact i can close the return line completly and have no change at all makes me wonder whats going on.

I dont want to waste 2 weeks of thinking its the fuel pump only to put a new one in and that isnt the problem.

Oh and yes i have tried a new filter.

Whats your thoughts?
Thanks

machine4321

Oh i should mention that when i pulled the vac line and psi went to 40 i took it for a drive and for some reason it got leaner almost across the board then it did at 30psi.

gsrhatch2356

First of all you have to understand that the injectors still have a max flow rate. which means that at some point no matter what the psi is on the rail that your only going to get so much in to the clys. it seems to me that there is nothing wrong with the pump and you should be looking at getting bigger injectors and a fuel pump. I dont know what your using to tune with but hopefully your using a wideband and have some sort of experince tunning. you can get some real basic tips for tunning off of hondata.com or in the force induction forum of this website. sounds to me though you need injectors to. its always better to get a decent injector size cause you can have a big injector with a low dwell instead of a stock injector that is maxed out on injector time ( they tend to overheat and surge and then fail) just more research is needed but I hope I helped a little

machine4321

Sorry,should have been more specific.
Dsm blue tops. with resistor box
yes i have a wide band.
and i have tuned a handfull of turbo cars.

Car runs great , but open downpipe leans out. after adding a bunch of fuel and endng up with the same a/f numbers it was clear that it is a delivery propblem. Probably maxing out the fuel pump. other then mabye a weak FPR (stock). I have a b&m adjustable but i would rater just leave the stock one on.
Thanks for the reply

H23_del_soul

If you have an AFPR why have you NOT installed it yet?!? Thats one of the first things you should have done (In my opinion) to try and resolve the issue, especially since you already own the part.

v8killaz

are you using the same map for open dp and exhaust on. because its obviously going to run lean if you just run open dp on the full exhaust map

machine4321

No i retuned for open downpipe.

I have not put the crappy b&m on cause they kinda suck at times. if i can keep the oem one on then i would prefer that. The fact my AFR got leaner with increased fuel pressure tells me adding the FPR isnt going to help .
Thanks

d16y8turbo

What're you using to tune? afc hack?

machine4321

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