I have a 1986 ranger 2.9 that is running excessively rich. There is black smoke coming from the exhaust, the spark plugs are soaked in fuel, and fuel is getting into the oil. What is going on here?

 

On the fuel rail that feeds the fuel injectors,is a fuel pressure regulator,. It has a vacuum hose connected to the top of it. Remove the hose and see if fuel leaks out. If it does, the regulator is faulty and needs to be replaced. Very common problem.

 

So I pulled the vacuum line and there was no fuel. Just to verify, I hooked up a gauge to the fuel rail and I get 40 psi. So something else is going on, any other ideas?

 

These are a few of the things that might cause overfueling,
fuel pressure regulator, (pressure can be ok, but still leaking fuel into intake).
If coolant temp sensor is providing false info saying engine is cold, could be providing excess fuel
Faulty MAP sensor,or vacuum to MAP sensor saying throttle is wide open , send more fuel.

 

So I replaced the fpr anyway and now I get 35 psi. That helped a little bit. I replaced the ect also which didn’t seem to make a difference. Something that is kind of weird is that I looked under the hood to find the map sensor and I found it with another map sensor zip tied to it. It’s like the previous owner bought one and didn’t need to install it so he just zip tied it in there for an extra. Anyway I installed that one and that didn’t seem to make a difference either. Also it seems as though it only runs rich at idle.

 

Could you please provide the 8th digit of your VIN ?

 

Before replacing any more good parts, we need some more info
Miles on the clock ?
How long have you owned this vehicle?.
How long has the vehicle had this problem?

Can you pull the two plugs on both sides, front of the engine , cyls 1 &2, and cyl 4 &5 ?
How do they appear, are they all full of carbon or are certain ones full of carbon?
If so which plugs are full of heavy carbon? Don't mix them up important , thanks.
Did you try to see if any codes were in the computer?
Check engine light Yes/No ?

 

Replacing your FPR didn't accomplish anything. You went from 40-35 psi, specs are 30-45 psi so you were well within specs, that was not bad and not responsible for contributing for your rich condition.. I know with an 86, information is limited but I would still check for any codes which may give you some direction other than just replacing parts and hoping you nail it. Did you monitor fuel pressure after shut down to see if the pressure immediately drops off which may indicate drippy injectors?
You can do pin point testing of components with a multi meter. Does your coolant temperature sensor for the ECM have the proper resistance for the coolant temperature it is seeing? Is the vacuum line for the MAP sensor in good shape?

 

The truck has 76,000 on it. I’ve only had it for a month now and it hadn’t ran for several years. The fuel pressure doesn’t drop when I shut it off. Every spark plug has carbon on it and is soaked with fuel. I am also now noticing that the smoke only appears at idle and light acceleration in first gear.

 

There is no CEL. I have not checked for codes and I am about to do that. I have not checked for resistance in the ect.