FC3Sdrift

iTrader: (5)

I've been pretty lucky with my car , no real issues in over 3 years 12000 miles.
S5 TII with AFC neo has been crazy reliable... there's a race ive been wanting to go to all winter NEXT weekend, my car runs good till right before

I first thought it was my injectors so i spent the last week getting those cleaned i put them back in only to be faced with the same problem
it started out when it kept boggin out at 4k at half throttle my WBo2 would be pegged at 10:0, i have alot of secondaries, i figured it just needed some tweaking due to the weather changes, its been getting really hot here now. the next day, it wouldnt rev past 4 k in boost or it would go rich and fart and crack, ( sounds like an injector problem so i started provoking it thinkin an injector was just sticking a little bit ) then the rpm it wouldnt rev past started getting lower but i could rev it up to 5-6k rpm in vaccum. i did a few things to my brakes at my dads went to drive the 12-14miles home and i had to pull over twice . just cruising along at about 2500-3000rpm my afr would be fine and then just start peggin my wbo2 to 10:0 and it would make the car shake and bog down then it would stop if i kept it at a constant throttle for a minute or 2 but any change in the throttle would make it go back rich and start shakin and bucking it got so bad a few times i had to just pull over, it would idle fine and rev up in neutral to 5-6k nice and smooth then i would try driving again. by the time i got home i had to shift at 2500rpm to just keep it from freakin out. i pulled my injectors they looked goo but got them cleaned redid my fuel line and vacuum lines, put it all back together thinking it should be good, it still doing it

What makes me think its my fuel pressure regulator is the fact that all 4 plugs were just completely black from it being super rich, and when i had pulled my fuel lines off there was crazy pressure there the line was spraying fuel out for a few seconds like the pump was still running, and i had taken off the fuel cap to relieve the pressure!!!
i think its making way to much fuel pressure or the fuel pump is working erratically? its almost like its in limp mode, but i could rev it up in vacuum

the pump is 1.5 year old Walbro 255lph and stock FPR

there were 2 instances like 2 months ago once i was drifting in a parking lot and when i left and was driving down the road nice and easy it started goin right rich. the same thing when i reved out 2nd and 3rd one time goin down a back road. it would pe pinned at 10:0 and i could rev it up in nuetral to clear it out then it stopped a few seconds later and i kept goin, i put heavy duty fuel injector cleaner thinkin it was that back then, i didnt really have any problems after till this
the engine has good comp still fires up no problem when its hot and a bit flooded

i also tried a different leading coil and different wires but no luck

jon0886

iTrader: (1)

FPR is definitely a possibility. Fuel pressure gauges can be bought for pretty cheap. Just get one and check your fuel pressure, then you'll know for sure.

FC3Sdrift

iTrader: (5)

i called around all the performance shops trying to get a FI fuel pressure gauge no one had one in stock, so i went and got a fuel injection fuel pressure tester
i would have prefered a gauge i can keep in the car all the time

florotory

also try to run a ground wire to the coils. Mine was doing the same thing and it ended up being that my leading coil wasnt grounded very well.

bostonspgs

iTrader: (1)

taking the gas cap off releaves pressure in the tank. there is always back pressure in the lines because gas expands so it will **** out until the line drains

FC3Sdrift

iTrader: (5)

i hooked the tester up , the fuel pressure is good theres no drop in fuel pressure when it bogs
im thinking it might be a spark issue, which would be shooting unburnt fuel through the exhaust
can you rev your car up in light throttle in neutral past 5k rpm in limp mode?
i'll try adding a ground to the coil.
im gonna take it for a little drive tomorrow and make a video
it kind of seems like limp mode ive been thinking maybe my omp crapped out but theres no burn marks or anything inside the ecu, i dont have a CEL i think i have an idea on how to make a light that will flash the codes.....is limp mode basically a spark cut?
it started doing it gradually over the 2 days i figure it would have just messed up all at once.
even now i can still rev to 3-4500 rpm before it goes rich and starts missing and loses power, and will shut off sometimes if i clutch in

its driving me nuts lol , i was hoping it was just something stupid i was overlooking i pretty much just need to spend tomorrow with the car and my ohms meter

JustJeff

iTrader: (13)

You don't need to rig up a light to flash for CELs all you need to do is take a wire and ground a single green female harness in the engine compartment on the driver's side near the leading coil. Simply ground that harness to your battery neg terminal. It's connected to the same bundle of wires as the Check Connector a 6 pin green harness that you'll find in fuel and emissions chapter F2-3. Part #12 on the diagram.

Get in your car turn the key to start and you'll see the CEL flash whatever codes you have. Long flashes = 10 and short flashes = 1. So 3 long flashes followed by 3 short ones would be 33. The codes will loop and repeat.

FC3Sdrift

iTrader: (5)

its a 87tii chassis...no check engine light. the fb guys use led's on those plugs

JustJeff

iTrader: (13)

Oh at the first post your said it's a S5 TII. In light of new information I suggest you rig up a check light :P

FC3Sdrift

iTrader: (5)

the motor and ecu is S5

florotory

I made a code reader for about $8 from radioshack last week. It is extremely easy. ill see if i can find the link on exactly the parts needed and how to hook it up.

florotory

http://www.fc3spro.com/TECH/HOWTO/ER...KI/zerror.html

Aaron Cake

iTrader: (1)

Also check the wiring around the pressure sensor. And the sensor itself.

FC3Sdrift

iTrader: (5)

yeah i came across an old post you made sayin to check that, if its the wiring it would be where i wired in my safc to read boost instead of tps.........

I just thought of this as i was writing this post, I have the stock boost gauge working , i could see if there's anything up with the pressure sensor. im still gonna check the resistance and stuff

thanks for te idea's guys
im gonna go start workin on it in a few minutes , i wanna have the proplem solved by today , i would hope with 8 hours a poking around with my multimeter can find something

FC3Sdrift

iTrader: (5)

No Luck,
the morning was such a tease i went out there added a ground from the negative battery terminal to the leading base plate just to try it , and i noticed the 2 bolts on the negative terminal were loose i tightened those hoping that was my problem, started it up and drove it for a bit , it was still missing, but was getting better it was driving normal for the last 5 mins , i could boost and rev it up a bit, i made 10psi at one point but my throttle cable was binding a bit keeping the idle at 1500, i went back home to adjust it, when i went to start it again to drive it more it was running like **** again it might be short or something it seems like it reacts to bumps also

the leading coil is getting 12v and the resistance between the 2 terminals is within spec
i pulled the fuel pump and checked all the connections in there it pumps fine
the fuel pressure is good
tried another set of plugs
i went over all my wiring
its gotten to where it even idles shitty now too
i tried a n351 ecu and it runs the same as soon as i start it

im pretty sure its not limp mode since i was makin boost and theres no change when i switch to the S5 N/A ecu

i think its my leading causing it to miss and shows up rich on my wb02

i still need to check my CAS

FC3Sdrift

iTrader: (5)

This is Bullshat!!!after everything i checked and all the little things ive fixed my car should be running friggen perfect,
the CAS is good 175ohms on both side
sparplug wires are .99 ohms so its good
i dont have a pressure pump so i cant check the pressure sensor properly, but i have it so my AFC neo reads boost instead of TPS, the throttle percentages look normal for the vacuum level

i took it for alittle drive again today, it cruises around with low throttle but it randomly with miss, but if i get to hard on the pedal it will start, i was cruisen around pretty decent today till went to go up a big hill then my car started running like complete *** after

i did try unplugging the pressure sensor while it was running, it idles the same i took it just around the parkin garage in first real quick and there wasnt any misses, but i didnt really push on it or anything

FC3Sdrift

iTrader: (5)

i finally made a tester i should have did it a couple days ago, cots like $13 to make ,i missed the codes the first time cuz i was so amazed at how well it worked hahaha
its my airflow meter , i thought it might have been that, when i would shake it it would stumble a bit i just figured it didnt like it , Im hoping its just the wiring at my SAFC
if not maybe i will test my JE50 VAF like the japanese use, or try to source one by the weekend

FC3Sdrift

iTrader: (5)

when i check the AFM with my ohms meter as per the FSM ,
i think something inside is screwed,
when i check the resistance between E2- VS is sometimes shows a reading thats withing spec but then it will just stop and i cant get a reading from it it just show infiniti
i can switch to VC without moving E2 and will show the resistance withing spec
does this mean AFM is pooched? lol probably didnt like the 16-17psi dropkicks to the plunger

florotory

sounds like afm is no good. it should be a consistant reading. if your getting a reading then it drops off that is what your ecu is see as well and will run rich or lean

FC3Sdrift

iTrader: (5)

I got a new AFM today, car runs awesome again!!!