1987 ford ranger running really ruff

[cory g]

Hello everyone,
I have a 87 ford ranger pickup, it is running extremely ruff. You can smell the exaust and it smells super rich and is even spitting fuel out of he exhaust. when I bought the truck the wires were cut on he oxygen sensor, so I put a new oxygen sensor in it hoping that it would help to lean out the fuel. The truck has duel tanks on it, but the back one is off and it is draining fuel out of the line when it is running. I don't know if the cadalltic converters are plugged too, the truck only has 65,000 miles in it. or maybe its a vacuum line leak? I wanted to go home this weekend which is 300 miles away and want to get this issue resolved today or tomorrow hopefully.


Any help would be greatly appreciated


Cory

 

[RonD]

One of the Cat converters jobs is to burn up excess fuel in the exhaust, this is why they run hot, so if system has been running rich for awhile then yes, while maybe not clogged they are no longer working if exhaust smells rich.

Cut O2 sensor wires means the computer has been running in Open Loop which tends to be on the rich side, since the Lean side will cause engine damage.
I assume the Check Engine Light(CEL) was on when you got it from the cut O2 wire?
If not does the CEL come on when key is turned on?
If not bulb is bad or it has been disconnected, never a good thing.

No CEL when key is turned on could also mean computer is bad and that is a problem, see if you can "talk" to the computer.
Good read here on how to do that: http://www.therangerstation.com/tech_library/OBD_I.shtml
Some Auto Parts stores will have OBD 1(pre-'95) readers, but not all, OBD 2(1995 and up) is what most have and they will not work with pre-'95 computers.
If you can get some Codes from the computer then it may help you ID some problems.

Pull out a couple of spark plugs and see what they tell you about combustion in those cylinders.
Google: Spark plug condition
Very light brown is what you want to see on the white part of the plug, darker means rich, black means very rich and possibly oil is coming in via valve guide seals.
If plugs look good then what you are smelling is bad cat converter exhaust.

Running rough?
More details please
If you have limited RPMs and low power then yes muffler or cat could have collapsed inside and is blocking exhaust flow.
Remove O2 sensor and start engine, O2 hole will give exhaust a way out, if engine runs better then yes, clogged exhaust.
If you can hear an exhaust leak at the exhaust manifold that will cause engine to run rich after new O2 sensor was installed.

With engine warm and idling, unplug the IAC Valve's wires, idle should drop to 500rpms or engine may even stall, either is good it means no vacuum leaks, if idle stays above 700 then you have a leak.

Fuel Pressure regulator(FPR) is on the fuel rail and has the Return fuel line connected to it, it also has a vacuum hose connected to it, remove this vacuum hose and check it for fuel or fuel smell.
Older FPRs can leak, and that fuel is sucked directly into the engine causing rich running and rough running.


The TFI ignition system is very old now so will always be in need of checking when engine is not running very well.
Good read here on this system: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

 

[Big Jim M]

A 27 year old truck with only 65K on it should really be a nice truck. The truck in your description sounds like it was rode hard and put up wet.
Does this truck actually show 65K of wear? Are the seats and pedals crisp and new?
Is the floor mat all nice and pretty?
It you do have an almost new truck it should be worth repairing the things needed to pass inspection and drive once more.
From your post my guess from here is that you won't be driving that ride home this weekend.
The alternative is to take it to a local mechanic and ask him what it needs to be road worthy.
Without all the proper tools it will be very hard for you to get this ride together in a day or two, even with the expert help available here.
Big Jim

 

[cory g]

Wow thanks for all the information! The truck starts easy but only idles at about 525 rpms, what I mean by running ruff is when its running it spits and sputters and it blows gasoline out of the exhaust pipe, and it doesn't sound like its missing. When you get it into the higher rpms it runs a little better but not great. Also when its idling it blows black smock out of the exhaust. When the truck is running there is no check engine light on, im away from the truck right now so I cant check if it comes on when the key is on before you start it. The truck has dual gas tanks, the rear tank is out of it right now, and the lines are just hanging. When the truck is running gas is trickling out of on of the lines, I assume this isn't right. Could these be signs of a bad fuel pressure regulator? Ill try pulling the o2 sensor out tonight and see if that helps.

Thanks,
Cory

 

[cory g]

I do belive that the truck has 65,000 miles on it, the pedels look like brand new, it still has the original floor mats in it too, and they have little to no signs of were in them. The seat is in good shape with a little bit of sun damage but that's it. The truck sat for awhile before I got it. im sure this is the reason why. The guy I got it from was too cheap to take it to a mechanic so he just parked it for while, then I bought it.

 

[Lone-Ranger]

Sounds more like a rusty fuel line/rotted connection somewhere. And are you sure its spitting raw fuel out the tailpipe? Have you checked the coolant level?

 

[cory g]

yeah im sure its raw fuel, no I havnt checked the coolant level, ill check it as soon as I get home though.

 

[RonD]

Check FPR as described above


It won't be clogged exhaust, so no need for O2 removal.
Clogged exhaust will always effect higher RPMs first, i.e. engine won't run better at higher RPMs as you described, it simply won't rev past a certain point because exhaust can't get out so new fuel can't come in.
It could be there is a piece of metal blocking exhaust that is "flipped out of the way" when pressure gets higher, but that would be a long shot.

FPR or leaking fuel injector would be my guess.

 

[cory g]

Ok, I agree with you, im really thinking its the fuel pressure regulator. Im going to stop by AutoZone and pick one up tonight. I will let you guys know how it turned out.

Thanks for all the help,
Cory

 

[RonD]

Check it first, vacuum hose will have fuel in it if that's the problem.

 

[Big Jim M]

Most likely that liquid coming out of the exhaust is simply condensation. If the thing has sat for a while then all your problems in the running can be plug wires and maybe a simple tune of the engine.
Do check the vac hose on the pressure regulator.
BTW good for you! 65K in a vehicle that old is indeed a rarity. I'd buy one in a NY minute!
Big Jim

 

[cory g]

Thanks, the mileage was the deal breaker for me, I got the truck for 500 bucks so im not to worried about putting a little money into it. I figured I could have a good running pickup with a lot of life left for around 700 bucks or so. I did check all the vacuum lines on it and they all appear to be in good shape. I just wish I could've got it from the original owners, ohh well. I will pull the vacuum line off when I get home.

 

[Spott]

As a side note: I've observed that any functional used vehicle is probably going to cost you around $5000.

Maybe you got it for $2500 knowing that it needs about $2500 more in parts, or maybe you paid $5000 and it's in great shape.

Or maybe grandpa gave you his old worn-out truck for free, and you're about to discover that it needs about 5 grand worth of new parts before you can really trust it long term.

 

[cory g]

so I put a new fuel pressure regulator in my truck last night, its running a lot better but isn't running perfect yet, it still seems to be running on the rich side, I also got a new set of spark plugs because im sure all of them are beyond fouled. The vacuum line did smell like gas too, there wasn't any coming out of it, but it defiantly smelt like it.

 

[Big Jim M]

The sparks don't fire at all if they are fowled. I would suspect wires before plugs. But maybe that is just me.
Modern plugs all last at least 100,000 miles. My older NEW cars have 150K and 165K on them and I have NOT even pulled and regapped the plugs!
Big Jim