please help mustang fuel problem

[chuck94]

i am getting black smoke. the map sensor is good. i replaced the fuel pressure regulator and also the 02 sensor. when the ignition is on the fuel pressure will not shut the fuel pump off yet when you open the fuel line at the regulator it has plenty fuel. you can also hear a hissing down inside the intake. can anyone please help. thanks fuel pump will not shut off i think it should in few secs after with key on!! any help appreciated

[Christine57]

You have a vacum leak. Computer sees lean condition and is riching up. The fuel pressure regulator may be defective also. Find vacum leak at intake.

[Killercanary]

Sounds like a possible two part problem. The hissing sounds like a stuck open injector, or its just the fuel cycling through the fuel rail and back to the tank. Use a screw driver to your ear or some other listening devise and try to pinpoint where the whistle is coming from to try and determine the leaky injector if it is one. As for why the fuel pump isn't shutting off. I've seen that due to a bad ground, a bad relay, or a fried EEC. Unfortunately its not an easy one to find. The return style cars do not have an electronic way of monitoring fuel pressure so its not a leaky injector that would be causing this dip in pressure and make the fuel pump keep priming. Check your grounds first, and then the EEC to make sure it is secure and the harness is nice and tight on it. Does the car have a piggy back chip? If so remove it, clean the contacts, and re-install it. i've seen bad connections there do similar things.

The vacuum leak could make sense while it is running, but it doesn't explain why the pump won't shut off when the key on engine off position.

[chuck94]

Changed Computer Still Doing Same Thing

[Christine57]

Did you check for a vacum leak at the manifold gasket? What exactly did you do to the car. Let's start from the beginning. If there is a vacum leak or injector leak, changing the computer will not fix it.

[chuck94]

I Changed The Fuel Pump Relay Put A 255 Walbro Pump In It Changed Computer Fuel Pressure 40 Psi New Plugs Redid Timing Changed Mass Air Any Suggestions Why Fuel Pump Wont Shut Off? Is My Fuel Pump Faulty?

[chuck94]

Also Put 24 Lb Injectors In It

[chuck94]

What Grounds Should I Check?

[DMmustangLX]

there could be a possible short to voltage causing the pump to stay on. normal pump operation will have a 3 sec. prime at k.o.e.o does the pump shut off or continuously run at k.o.e.o?

[John4cam]

You say your map sensor is good and you just changed your maf?? Is the car speed density or mass air?

[chuck94]

Didnt Change Map Sensor Fuel Pump Constantly Runs With Key On

[Sonic03snake]

Was the car originally an auto?

[chuck94]

I'm Not Sure If It Was Originally A Auto

[chuck94]

Also Car Has Like Flasher Relays For Fuel Pump Instead Of Like Regular Mustangs

[Sonic03snake]

Ive been told that if it was an auto and the auto wiring pigtail to the trans hasn't been changed it will burn up the 5 spd computer.

[chuck94]

What Fuel Pressure Should I Run I Got Hci And Few Bolt On Stuff

[92306gt]

What Fuel Pressure Should I Run I Got Hci And Few Bolt On Stuff
32-35

[chuck94]

Sumtin Weird With Key On If I Tap On Fuel Rail It Makes A Clicking Sound Then It Will Fire Up Any Suggestions? Clogged Fuel Rail?

[KeystoneJohnny]

Sumtin Weird With Key On If I Tap On Fuel Rail It Makes A Clicking Sound Then It Will Fire Up Any Suggestions? Clogged Fuel Rail?

Chuck, you sure the fuel injectors you got are not the problem. Is this the 93 you are talking about?

[chuck94]

yea its the 93 i tried two sets injectors

[DMmustangLX]

Sumtin Weird With Key On If I Tap On Fuel Rail It Makes A Clicking Sound Then It Will Fire Up Any Suggestions? Clogged Fuel Rail?


if u are tapping on the fuel rail and then it starts u could be getting the injector driver to be making contact with the injector causing the injector to pulse. that clicking noise is the injector opening and closing. are they stock furl rails? aftermarket fuel rails?

[chuck94]

STOCK FUEL RAILS IF I DONT FIGURE IT OUT SOON A JR VICTOR AND CARB GOING ON IT :rofl:

[DMmustangLX]

STOCK FUEL RAILS IF I DONT FIGURE IT OUT SOON A JR VICTOR AND CARB GOING ON IT :rofl:


hahaha are u injectors new or used ? do u have noid lights check to make sure your injector drivers are firing if they are i would say go to aftermarket fuel rail and check ur injectors for continuity there mite be an open in one of ur injectors. from what u have told me i would be looking at the injector drivers first :goodidea: let me know what u find

[chuck94]

now i got it running again but wont start when cold gotta spray carb choke cleaner in throttle body any suggestions

[mustang50lx]

Do you have access to a scanner? I would check the parameters on all the sensors with a scanner. Intake air temp. sensors used to get carboned up and cause problems like hard starts and very rich conditons. You could try unplugging it. Possiblly coolant temp sensor too. Is there crossed up or grounded wiring? (Pinched in the Bellhousing?) If you can get a scanner on it it should be pretty easy to figure out. Try unplugging the MAF sensor. If they get anything on the sensing wire it drives the computer crazy. Even though the MAF sensor is new it could still be bad. Is there fuel in the fuel pressure regulator vacuum line? If so it's bad. Where do you live? If it's not too far away and you can wait until next weekend I could bring my scanner home from work and take a look at it. If the fuel pump is staying on with just a relay replacement, it sounds like the relay is bad or wrong.

[chuck94]

i put two new relays on it for fuel pump i dont got a scanner i live connellsville pa i'd pay u if u could do that for me as nothings cheap anymore thanks

[chuck94]

i'll try them sensors maybe b4 next weekend

[mustang50lx]

I am going to hook my scanner up to my car to make sure I can get live data. I know early EEC 4 cars you couldn't read data. I am pretty sure by 93 you could. Either way I can at least run some self tests and see if I can get any codes. You should be able to just unplug at least some of those sensors. If you unplug thwe MAF the car goes into limp home mode and will run without it. Anyway just PM me before Friday if you want me to scan it.