RB running rough, no idle, super rich. wtf MAF

[godzilla_753]

been having so many headaches with this car, Im at my wits end. I finally got the wiring bugs figured out (i think).. and now its got more problems.
I have a neo rb25det thats starts up and runs super duper rich, stumbles at idle and and doesn't want to rev up. In addition it seems i have a boost leak of some sort because the gauge is reading zero vacuum, and zero boost when I rev it up.

Ive checked:
TPS voltage @ .7 volts with the switch on, cant seem to get it any lower.. should be .4 to .5
MAF voltage is showing .2 volts with switch on, and around 1.7 volts @ 2k rpm which is dead on.
coolant temp sensor voltage is also dead on around 2.7 volts when i tested it after having ran it for a few minutes. (should be 3.5cold, 1.2 hot)

have yet to check o2 sensor.

The car seems to run much much better with the MAF unplugged, but obviously it wont rev past 2500. it idles much better, and I can also hear turbo flutter when i rev it, something i don't hear when i plug it in oddly. as soon as i plug the maf back in it starts taking s*** and goes back to pig rich mode.

now the difficult part is that this is a NEO motor so not many have experience with it. On top of that I adapted a GTR throttle plenum to it, so the vacuum is a little tricky with ITB's. In addition I had to remote mount the IACV..Im gonna go back and double check all that, but taking vacuum out of the picture it should still idle and drive no? I don't understand why it wont hold idle and why its running so rich. I double checked my fuel pressure and its a little high but I cant get it any lower without good vacuum.

Forget that its a NEO motor, i know this is something small that Ive overlooked and probably common to all rb's so don't be afraid to shout out a suggestion. What controls the idle on these things? I haven't tried messing with the IACV yet.

like i said any suggestions would be great.

thanks for reading

[Darius]

First, is it misfiring at all or does it run smooth but rich?

Second, pressure test the charge piping. If there is a leak, it will suck in unmetered air and cause idling problems. It shoudln't go rich, but maybe the ECU is overcompensating. Who knows?

Third, check the IACV for a good seal and that the screw is properly adjusted. How did you "remote mount" it and why?

Fourth, pull the vacuum line off of the fuel pressure regulator to make sure the diaphragm isn't torn. If it is, fuel will pour out of the port.

Fifth, replace the O2 sensor if everything else checks out okay.

Otherwise, like you said, the TPS, AFM, and coolant temp sensor appear to have normal operating voltages for idle.

[mixeds14]

do u have the correct maf? n i would also make sure u dint mess up any of the injector orings when u switch everything out.. take ur plugs out n check the condition of them.. check ur fpr also

[godzilla_753]

1)When I plug in the maf it starts stumbling and misfiring, becomes very slow to respond to throttle inputs. When the MAF is unplugged it doesnt misfire or stumble and revs up quickly and seems to boost.

2) Im checking for boost leaks now, so ill get back to you on that.
3) On the NEO motors the IACV has air and coolant running through it. After adapting GTR plenum on there wasn't really a good place to put it so i mounted it remotely and ran the appropriate hoses to it. Ill put up a pic of the setup for better understanding.
4) Im running an AEM FPR, and the diaphragm is OK, I pulled off the vacuum line and no fuel came out.
5) my MAF reads E60 and has a PINK tag. Im pretty sure its the right maf but who knows if its working correctly. Would the maf voltages be off if it wasnt working correctly? How do you test these things?
6) I dont think the injector orings are leaking, I think I would see it pretty easily since the fuel rail is a top feed and the injectors are right there. Plus it runs and idles fine with the MAF unplugged
7) ill pull the plugs but I can say pretty safely that theyll be black as hell

here are some pics of the setup.





excuse all the nasty wiring and mess, Ill be taking it all apart to powdercoat and reloom the wiring once i get it running

[godzilla_753]

I pumped up the system with some compressed air and found huge leaks around the 5th and 6th runners. Looks like the metal gaskets between the flanges I welded on and the ITB's are leaking pretty badly back there.

Could this be the reason? I also went and picked up another MAF for it. It seemed to rev up a little better but it was hard to tell.

[mixeds14]

man i would fix all the leaks first, that may have something to do with it if its leaking that bad.. n when your injectors leak, u cant tell just by looking at them, if the plug is wet or ur oil smell like gas really bad than thats a good possibility that u have an injector leaking..u already know its rich as hell from ur plugs being so black but do they look wet.........

check ur oil if it smells like fuel, i would change the oil (n plugs)before u mess with it cause that could give u more headaches than u already have..

check ur maf wiring n make sure its right, u may have the signal n 12v hook up wrong..

but, if i was u, i would of gotn the motor up n running before u switch to the itb's that way u could fixed all the little bugs on there if any...

btw just curious, what adapter r u using for the itb's,, u got a pic? im interested in that maybe i get myself a greddy mani..

[godzilla_753]

Ha that exactly what my dad told me, get it running before i finger it. either way im gonna tear it apart and get some new gaskets in there and see if it help. I double checked the maf wiring and its good as far as I can tell. I got the signal and ground wire running through the shielding, with the 12v wire outside of the shielding. Ill probably get some new orings for the injectors since its an easy fix and their right there. you know off hand what is the usdm equivalent ?

and on the ITB's I cut the runner of the intake mani, played with them a bit to line up right and then welded on new flanges to mate the itbs to. from there on it was pretty simple hooking up the throttle cable and stuff. the only tricky part it is hooking up the IACV valve, wich as you can see from the pics i had to relocate to the passenger front under the fender