RB SPECIALISTS... "HELP ME PLEASE"

[shally2186]

ENGINE::RB20DETCAR::89 240sx COUPE

ok guys heres my story..when i got the car it was supposedly rebuilt.he supposedly had a air/fuel controller hooked up to the ECU and got stollen..any way,the RB now is running @ 30lbs of fuel pressure (with vacuum) and is blowing black sh*t everywhere likes its running too rich.. ..just replaced the spark plugs tonight and the car is gettin sumthing that sounds like a fuel cut now ..anyway i tried reset'n the ECU by turning the knob on the back of it..however the wires to my ecu are all cut and messed up because of the stollen air/fuel controller that got ripped out of it...think i need a whole new wiring harness?..ne ideas on whats goin on w my RB project???geatly appreciate any advice



Modified by shally2186 at 8:35 AM 12/22/2007
Modified by shally2186 at 8:42 AM 12/22/2007

[nizmo zilvia]

so whats your question?

[shally2186]

lol well wats the reason for its acting like fuel cut @ 4-5rpm and still run so rich to paint walls black??like i said the fuel pressure is only set @ 33 w vacuum..should be higher i kno but the car is running too rich as it is
Modified by shally2186 at 10:12 PM 12/15/2007

[Sky80]

You have a boost/vacuum leak somewhere, start looking for leaks

[S13 240SX]

check the air/fuel settings and mass air flow?

[shally2186]

You have a boost/vacuum leak somewhere, start looking for leaks

yea thats wat i was thinking might be my problem...is there a easy way to find ne leaks?

[Kisorperformance]

ok lemme get this straight.... it had some sort of afc on it and now it dosen't right....

and this engine was in the car before you got it....

and you have broken wires to the ecu......

first fix the wires.

if that doesn't help then find out why he had the afc on there..... does this engine have bigger injectors installed???

gotta get some details first

[240z4u]

Sounds like the maf wires are cut. Read the service manual and test the plug at the maf. That will put the car into limp mode.

As said above, fix the wires.

Evan

[Kisorperformance]

if it had a afc on it, it may have mods done therefore it needs one to run correctly

[Joe]

no it doesnt lol

AFC's are worthless. the only thing they do is play hell with your factory ignition map. a stock ecu will be fine with every bolt on you throw at it untill you upgrade the injectors.

[BoostFab]

the the wires where the afc (safc??) was wire in; first of all get your cut wire fix if it's not correct.

[Kisorperformance]

no it doesnt lol

AFC's are worthless. the only thing they do is play hell with your factory ignition map. a stock ecu will be fine with every bolt on you throw at it untill you upgrade the injectors.

ok, hello??? are we missing the point i'm trying to make here.....

DO YOU KNOW FOR A FACT THAT THIS ENGINE HAS STOCK INJECTORS?????

ok maybe now it's a little more clear.

for whatever reason this thing had additional tuning. ie: the stolen AFC. yes fix the f'd up wiring first, if you still have a problem..... you may need to aquire either stock parts....... or tuning equipment of some fashon

hard headed argumentative people..

[nizmo zilvia]

why has everyone been so harsh to Karmin lately. Hes just trying to help with truthful posts.

[Joe]

ok, hello??? are we missing the point i'm trying to make here.....

DO YOU KNOW FOR A FACT THAT THIS ENGINE HAS STOCK INJECTORS?????

ok maybe now it's a little more clear.

for whatever reason this thing had additional tuning. ie: the stolen AFC. yes fix the f'd up wiring first, if you still have a problem..... you may need to aquire either stock parts....... or tuning equipment of some fashon

hard headed argumentative people..

listen here noob. an AFC is ALWAYS 100% WORTHLESS ON MOST ENGINES.

its a ****ing garbage bandaid to a REAL standalone. when you change your airflow values to trick your computer to add more/less fuel you ALSO change your ignition maps which can wreak HAVOK on your engine and cause nothing but problems

AFC'S ARE s*** AND SHOULD NEVER BE USED

regardless, 95% of people who put them on have absolutely NO need for them even if they do have upgraded injectors.

the odds of him having bigger injectors anyway is slim to none.

[shally2186]

yea I have a WALBRO 255 fuel pump and 444 injectors...wat now???

Modified by shally2186 at 6:53 AM 12/18/2007
Modified by shally2186 at 9:49 AM 12/26/2007

[Joe]

then you should be running a chipped ECU and REAL tuning. not an AFC

its a timebomb.

thats what now.

[shally2186]

the AFC was just what the kid said was in it b4 i got it...i was told that i dont even need a AFC..ok well with them injectors and my stock ECU (i think),whats a reasonable fuel pressure with my upgraded fuel system?

[Yellow4g63]

the AFC was just what the kid said was in it b4 i got it...i was told that i dont even need a AFC..ok well with them injectors and my stock ECU (i think),whats a reasonable fuel pressure with my upgraded fuel system?

You shouldn't even try to drive this car till you get **** figured out. Since it did have a afc in it I'm sure the wire for the airflow meter is cut. Also you don't seem to know anything about electrical setup and if the injectors have a resistor box and what kinda of injectors they are. If you can't figure it out you should pay someone that knows. Or you can take some Hi res pics and post them and "maybe someone can help... maybe". Get your ecu chiped with a good program talk to CarlH about that.

[JPsNissans]

DO YOU KNOW FOR A FACT THAT THIS ENGINE HAS STOCK INJECTORS?????

Nice job, you were right on the money.

shally, this has been said but you need to find a real tuning solution.

You can only go so low on the fuel pressure before your fuel injectors will not function correctly. You cant just crank it down to super low fuel pressure to compensate for the larger injectors and big pump and expect it to run right, though Im sure people have gotten away with it before.

[shally2186]

ok..where should i be at with my fuel pressure then??w and without vaccuum?

[Kisorperformance]

set it to 40-42 with the vacume line off the regulator.... that should put you in the mid 30's on vacume and 1:1 increase with boost... ie: 15psi boost then fuel pressure will rise to 55psi based on 40 nominal

and on a side note, watch the noob comments..... i may be new to this board but i've been building engines and racing everything with wheels for about 20 years now

[craz4240]

Sounds like you have a hard road ahead of you......your car is not even close to being drivable by the sounds of it.

SAFC's are ok for very minimal adjustments..and only paired with a good tune on the ecu,no matter what you set the safc for it will not correct your injector lag and k values correctly and will shove timing down the throat of your motor.

So that being said like others I believe you have one of a few things going on......you have a vacum leak,you have the mafs wire unhooked thus not giving the ecu it's MAFS voltage reading thus not allowing the injectors to fire properly,however if your ecu is not tuned for 440cc injectors then that is somewhat of a moot point as well seeing is how even with the AFM wire hooked up it will still not run properly.Also check the resistence of your injectors and see if they are high or low impedance...if they are low ensure you have a resistor pack wired in as you will fry your ecu without one.

Buy yourself a wideband,a Carl H ecu tune,and pay him to redo your harness so you can ensure thats all done right.And for the love of god do not run your car till you get this stuff fixed up.Check your injector resistence,then pull your CAS to ensure you have firing coils and injectors,and get that ecu and wiring fixed up.

[shally2186]

alright,sounds great so far...i was guessing that i had alot of work ahead of me but figure it will all pay off in the end..im sorry for not knowing too much about my car,cause ive only had it for about 7months and its my first turbo/nissan...i appreciate all the help guys...on another note wat do u all think about a set up like this??

[shally2186]

so without vaccuum i set my fuel pressure @ 42..the car now runs like **** when above 3000rpm...so im told and believe that ecu needs chipped

[Darius]

I highly doubt your car needs to be "chipped" at the mod levels you're at. There is a either a boost leak somewhere or your MAF wiring is faulty.

At least your fuel pressure is correct now

[shally2186]

i have alil exhaust leak i think @ the block..does that really matter on how it runs?

[Joe]

pre turbo, yes.

[skrappy]

I have a solution to all of your ECU/fuel problems.

POWER FC or HKS F CON

Thats a simple solution to hard problem. Now that i have gotten that out of the way i will concur with a lot about the AFC. Yes they are garbage in my book. They are worthless in the wrong hands. BUT in the right hands i have seen some sick tunes with a SAFC II and some mild upgrades ie. Injectors, cams, turbo. Granted these cars were barely pushin 300 PS (WHP) but still the tunes were setup right. So i agree with a lot of what is said about the AFC but given the right person doin a tune and what they know it can serve its purpose in a legit way. The NIHON-JIN's are godlike when it comes to their tuning abilities

[craz4240]

If he's running 440 cc injectors he needs a tuned ecu and/or a resistor pack.

[shally2186]

well this is what i was told...the car was running fine with a tuned ECU..then when the next kid got the car he f'd it all up and put a AFC on it...it had NO AFC and HKS knock off BOV that wouldnt close..the car ran like **** until i got a new BOV..then it ran alil better but still was hesistating until u hit 3k rpm..so i was told about resettin the ECU with the lil turnb knob on the back of it..i reset it and the car was runin awesome sept for sumthing like a fuel cut around 4-5k rpm...i was told by the guy who built the car that the ECU needs retuned and sumthing about the resistance prolly on my fuel injectors..btw i was right the first time..they are 444 injectors..i was told theyr was no such thing but i checked and they are