boost issues

[AsleepAltima]

ive got boosting issues in 1st and 2nd gear. pretty much nonexistant in 3rd, 4th or 5th.
my setup - the stuff that matters, anyways
95 blacktop - fresh rebuild
87mm cp's
cosworth headgasket
jwt ecu
740cc injectors
j30 maf
gt2871 - 20lbs/boost
bc stage 2 cams

i just replaced the o2 sensor, replaced all the couplings so no more leaks, made a hard intake pipe today, set tps to .45, timing is set to stock, plugs gapped to .028 (gapping them smaller made no difference), fuel pressure set to 38-39 w/o vacuum.

my problem is slight stumbling while cruising around 40 in 3rd - mostly when the engine isnt fully warmed up, but still a little noticeable. the big issue i have is when i start to get heavy on the throttle in 1st or 2nd, i start getting bad misfires about 5k rpm to redline. this pretty much doesnt happen at all from 3rd gear on.

ive tried setting the gaps smaller, replaced the tps, looked for and found boost leaks and fixed those and i raised the fuel pressure to 40 and it made no difference.

kind of at my wits end right now. the engine has maybe 1500 miles on it so far.

[ultimateirving]

what is your j30 maf connected to? rubber charge pipe, or metal with silicone couplers

[AsleepAltima]

metal with silicone couplers. just fabbed that up today as a matter of fact. didnt make any difference. :(

[s14>integra]

sounds like a fueling issue. which could be caused by your maf. Have you checked the signal voltage going form your maf to your ecu? i would check to make sure that's within spec. and that the ground is right.

[AsleepAltima]

i will check the maf signal voltage, but ive been thinking more and more about that ground. i didnt do the wiring on this swap so i dont know what it looks like. the coil pack part of the harness is grounded but honestly, i dont remember seeing another one, now that i think about it. i know the one that goes on the back of the head isnt there... i need a wiring diagram to see where all the grounds are. i think im gonna dig up my fsm and see what it says.

[AsleepAltima]

grounded the 2 center wires on my maf and it made no difference... this kind of stupid shit pisses me off. argh.

[s14>integra]

one of the ground wires on your maf goes to the ECU, the other goes to a body ground. Those things can really make a difference. If you need a wiring diagram for your car i can help you out. What year is your car?

Also, this may sound silly, But is your tune for that setup? I would also try contacting JWT and see if they can help from their end.

Does your car drive normal, but when you mash it and build boost quickly it falls on its face? what about if you build into is slowly? My car would misfire and stumble hella bad when i mashed on it in 1st-3rd like yours and it was because my 4th cylinder spark plug wire was fucked up just enough that it couldn't handle going into boost, so i would check those too.

WEll i just remembered you have coilpack's since it's an SR.
If you have a ohm meter you can check the resistance of each coilpack and findout if they are good or not.

Also, do you have a wideband? what are your af/r's when it starts stumbling?
You could also double check your timing again.

[rb25_s13*CHUKI]

Did it do this before the build? or was it after you did the build

[AsleepAltima]

one of the ground wires on your maf goes to the ECU, the other goes to a body ground. Those things can really make a difference. If you need a wiring diagram for your car i can help you out. What year is your car?

Also, this may sound silly, But is your tune for that setup? I would also try contacting JWT and see if they can help from their end.

Does your car drive normal, but when you mash it and build boost quickly it falls on its face? what about if you build into is slowly? My car would misfire and stumble hella bad when i mashed on it in 1st-3rd like yours and it was because my 4th cylinder spark plug wire was fucked up just enough that it couldn't handle going into boost, so i would check those too.

WEll i just remembered you have coilpack's since it's an SR.
If you have a ohm meter you can check the resistance of each coilpack and findout if they are good or not.

Also, do you have a wideband? what are your af/r's when it starts stumbling?
You could also double check your timing again.
ill try to answer both of you at the same time...
yes, the tune is for this setup. the dude i bought it from a few years ago, used all of his deployment money building this car. all i changed out was the fpr and the turbo. i went from the gt28 to the 2871. it actually ran great before the build, but the oil rings came apart on the #1 cylinder and tore up the walls so i had it bored out to 87mm and used the cp pistons. it ran great for a few hundred miles but developed this stutter.
heres my thinking - something worked its way loose, like a ground OR the fuel pump isnt up to par (according to him its a walbro 255 - but im going to use the spare walbro i have and replace it) or the fuel filter is dirty/clogged. the car sat for about 2 years while i had surgery and deployed. i should have changed out the filter during this recent build but i figured since the system stayed closed and it ran good after the build that it was ok. i have extra coil packs from another build i had but i checked the ohms on all of the coils i have and theyre all consistent. maybe a cracked boot?
just stumped right now. i know its gotta be something stupid. its not head lift or the oil would show it. im thinking fuel or ground related at this point.

[s14>integra]

Ok, that clears a lot of things up. Is your walboro really loud? They tend to get louder before they eat shit and die. I wouldn't be suprised if it was your fuel pump and that sounds really plausible. If you have another fuel pump i would try it out. i think your on the right path with the "something came loose". If your car sat for 2 years i would definitely check the whole fuel system. It's not to hard to pull the filter and i don't think they are expensive either.

*EDIT* Also, check the spark boots for cracks cuz the spark can jump from the boot to the block under higher pressure like when you give it more throttle.

[AsleepAltima]

as far as i can tell, im not suffering from the loud walbro symptoms yet. i know for a fact the pump in my altima is a walbro so ill definitely swap them out. i did replace one of my fuel lines - theyre all ss braided lines and one of them split from sitting for so long and there could be pieces of the old one in the filter, now that i think about it. and youre right, theyre not expensive at all. ill get one tomorrow and slap it on if its not raining. otherwise, i think im going to pull the coil packs too and check all the boots for splits. my number 2 coil pack harness melted a couple years ago but i havent noticed anything odd from it and when i pull it while its idling, the engine stumbles so i know its working. i think i will also add some extra grounds this week too. thank god i have my evo to drive while this ones down. lol

[s14>integra]

^ dam. i wish i had an evo to drive lol. your coilpack could still work but not provide enough pressure to handle boost so that pull test doesn't exactly work. It really sounds like you have fueling problems. So i would definitely do the fuel filter first, then check the walboro. then park the 240 and mob around in the evo

[AsleepAltima]

yeah and the fuel filter is definitely easier and cheaper to deal with. lol
the evo is nice, but its not as fast. but it IS pimpin though. lol

http://sphotos.xx.fbcdn.net/hphotos-prn1/538630_2871934993317_956034961_n.jpg

[AsleepAltima]

so it wasnt the fuel filter. gonna recheck and zero out the tps. gonna use the ground wiring schematic that s14>integra gave me and see if i can figure it out. if that doesnt work out, then i might swap out the fuel pump for the other walbro that i have.