car running super rich ( help )

[black96gts]

it was doin the samething with the aeromative fpr so i put the stock fpr back nothing changed

 

[justinschmidt1]

tune

 

[black96gts]

but alot of people have told me that it should be ruuning good without a tune with the 255 fuel pump

 

[silver 4.6]

if theres an upside, its not running lean and granding your engine, so you have plenty of time to figure this out before something blows.

 

[black96gts]

it even turn off by itself cus its too much gas too rich all u see is black smoke and the car wont start .. i have to disconnect the plug from the fuel pump and reconnected it .. back to start the car , the if u put new spark plugs and u drive the car for 15 min u have to put a new set of spark plugs and the car wont accelerate right .... i will have to take the risk and get a tune to see if that fix the problem

 

[Gregor185]

i put a 255 pump in my 96 and ive had no problems at all

 

[black96gts]

i dont know if every car itrs different

 

[Jrgunn5150]

it was doin the samething with the aeromative fpr so i put the stock fpr back nothing changed

You need to check the fuel pressure at the rail, either your regulator or FMU is screwed up.

 

[black96gts]

whats the fmu?????

 

[Jrgunn5150]

whats the fmu?????

Fuel Management Unit, it bumps teh fuel pressure in response to boost. If your car is boosted and untuned, and not blown up, it must have one.

 

[black96gts]

it doesnt have one .......

 

[Jrgunn5150]

Then you have serious issues.

Exactly what DOES your car have? It can't run stock injectors with a blower and no FMU, and it can't run bigger injectors without a tune.

Tell me exactly, what injectors, what MAF, what tune are you running with your procharger?

 

[black96gts]

ok last month i took my car to a dyno and my tuner made a program tu start the car with 39 injectors .. mafia .. and a aeromative fuelpressure regulator .... the first pass car made 328rwhp at 4k rpm cus i had the stock fuel pump ... but i could drive the car fine .. so i put a 255 pump last week and at that moment the car start having the problem .. so i took everything back to factory .. stock injectors fpr and took off the mafia and still have the same problem :dontknow: :angry7:

 

[2002BLGT]

did nobody read line 3 of my earlier reply ,


CHECK THE FUEL RETURN LINE AT THE GAS TANK , YOU PROBABLY PINCHED IT CLOSED WHEN YOU PUT THE TANK BACK UNDER THE CAR , THIS WILL SPIKE THE FUEL PRESSURE

 

[black96gts]

how do i check that

 

[2002BLGT]

how do i check that

pull the gas tank back out

 

[Jrgunn5150]

You still need to check the pressure at the rail, determine what it is, then go about diagnosing the problem.

 

[2002BLGT]

I agree , but if all he changed is the fuel pump imma bet my money this is the problem and his fuel pressure is probably around 80-85 psi

 

[Jrgunn5150]

I agree , but if all he changed is the fuel pump imma bet my money this is the problem and his fuel pressure is probably around 80-85 psi

You're probably right, but the fastest way to find out is to check the pressure at the rails, like I told him two days ago.

 

[black96gts]

ok guys i just put a fuel pressure gauge in the fuel rails ... the pressure is 35