93 v6 4.0 ranger

[josh4223]

Hello came here for some help have a issue with my ranger running rich basicly choking itself out. Have changed the fuel injectors map sensor coolant temp sensor fuel pressure regulator fuel pump assembly and o2 sensors but it is still choking itself out black smoke coming from exaust pipe as well. I thought maybe a ecm problem possibly? Also have changed the motor as well and same problem so I'm at a loss. I hope you all can help thank you in advance.

 

[racsan]

I A C valve possibly? thats what acts as a “choke” on efi fords. Mine came unplugged (locking tab on connector broke) and I had to keep my foot on the gas pedal to keep it running until it warmed up a bit. Fixed it with a few zip-ties. Dont overlook the air filter, would have to be extremely dirty but I suppose it’s possible.

 

[josh4223]

I have replaced that as well but I'll double check all connections are good. Was thinking maybe ecm has a code stuck in it but I don't know how to reset the ecm.

 

[RonD]

Welcome to TRS

If you can test fuel pressure first that would be best, 30-40psi running is expected

But with all your changes it will be harder to diagnose, "new part" just means NEVER EVER tested part, lol, 40 years ago it could have meant "working and tested" but not anymore

So with hard evidence of correct fuel pressure then you would be left with PCM(ECU)
Pull it out and open it up, should be nice and clean inside
There are 3 radial capacitors, blue or black, that can leak/fail, under $5 to replace, common issue after they get 20 years old
But could just be PCM failure
You can use a 1993 or 1994 PCM from 4.0l Ranger with matching transmission, PCMs are made differently for manual trans or automatics
2WD or 4x4 doesn't matter
And your 1993 shouldn't have Cam sensor or EGR valve unless it was from Calif. originally

car-part.com
Its a good place to look for used part in your area
"Computer Box engine" is what you want
Use your zipcode of course
Search

Then it will ask for specifics, engine size and MT or AT
On your PCM's label there will be a part number, the last 2 letters are what you want to match but do NOT need to match in 1993/4 models