93 ranger 4.0 blowing black smoke


Duaneg

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Hello all, hoping for some help. My 93 ranger 4.0 has been running very poorly. It doesn't want to start. For some reason it only starts when its very warm out. Like above 80, and dry. I don't know why. If its cooler, it wont start, just cranks. When it does start, it runs very rough, and blows black smoke. I want to pull codes, but I seem to be missing the small plug that goes into the OBD1 scanner. The check engine light is on, so I know there are codes. I know its supposed to be with the large connector, but it is absolutely nowhere to be found. Since I haven't been able to get codes, I have been pretty much throwing parts at it. Changed plugs and wires, new fuel pump, and filter. New MAF, new idle air control valve, cleaned the grounds. Pulled out the coil, and cleaned it up. Today I pulled the computer out and looked for issues on the board. I have heard about the leaking capacitors, but found no evidence of it. Is there a way to test the computer while its out of the truck, or a way to get the codes while its out of the truck? It sucks I cant find that little connector anywhere. Is there a way to bypass it? Thanks for any help
 


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kimcrwbr1

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Do you smell fuel in the vacume line going to the fuel pressure regulator?
 

Duaneg

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No, don't smell gas, but when I turn the ignition on, I hear a electrical humming sound coming from under the hood. Is that normal? Secondary fuel pump or something?.
 

chewy012

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A constant hum from under the hood? If you have a stethoscope, or a long screw driver, you can listen to the injectors. If one is buzzing non-stop, it's faulty. Should be a tick tick tick tick tick tick tick.

Sent from my VS988 using Tapatalk
 

AdirondackRanger

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My credo
I brake for leaves that could be frogs
sounds like fuel delivery issue. too much..
 

RonD

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Follow kimcrwbr1's suggestion

Behind the alternator on the lower intake is the Fuel Pressure Regulator(FPR), it has the Fuel Return line attached AND a Vacuum hose
If FPR leaks gasoline is sucked into the engine thru this vacuum line, causing it to flood out and the Black smoke
So check that vacuum line for gasoline.

A remote possibility is a suck open fuel injector, since you changed spark plugs if an injector was stuck open or leaking that spark plug would have a black tip, lots of carbon build up, did you see that?


You don't need an OBD reader to get the code(s)
You just need to count flashes of the Check Engine Light(CEL)
OBD port will be in engine bay attached to outside of fuse box or next to it
You need a short wire to make a jumper

Watch short video: https://www.youtube.com/watch?v=X07hu0kAuzE

One goof in the video, to clear the codes, turn on key with jumper in place, wait for codes to start flashing then pull out the Jumper wire, then turn off the key, codes should now be cleared

1993 will use 3 digit codes, found here: http://www.therangerstation.com/how-to/ignition-charging-computers/obd-i-diagnostic-trouble-code-dtc-applications-ford-3-digit-codes/



An electrical hum in engine bay is most likely a failing relay
Open engine fuse box and check by putting your finger on each relay while noise is present, you will feel it vibrating
 
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Duaneg

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I had a chance to work on the truck again. What I thought sounded like an electrical hum, wasn't. Sounds like it's coming from the fuel pump regulator. Sounds like it's loosing pressure. I pushed the shrader valve and fuel is slowly coming out. Very little pressure. I unplugged the fuel pump relay and the sound went away. Most likely fuel pump regulator? Thank you for the help on where to look. Sorry it took so long to reply
 


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