Shoot me now!!!

[Byron Hillegas]

I am working on a 1993 Ford Explorer that belongs to my girlfriend. She is the third in her family to own this vehicle in an apparent long line of people that don't know what preventative maintenance is. Her kids call it "The Ford Exploder". To the problem... Vehicle was running okay except for a slight miss. Shut vehicle off & upon restarting, it ran really rough, uses a lot of gas & is spitting what she refers to as "black juice" out of the tail pipe. No foul smell from the exhaust as with a stopped up catalytic converter & the vehicle has plenty of power. DTC's showed oxygen sensors. There are the repairs I made:

Oxygen Sensors, Platinum Plugs, Wires, Intake Gasket, Driver's Side Valve Cover ( 2 Bolt Holes Rusted Out ), Valve Cover Gaskets, Thermostat Housing ( Almost Rusted Through ), Thermostat, Idler Pulley, Tensioner Pulley, Serpentine Belt, Heater Hoses, Radiator Hoses, Flush Radiator ( Heavy Deposits From Running Water Instead Of Antifreeze ), Swapped Heater Hoses At Heater Core. ( They Were Backwards Preventing Her Heater From Working. )

This is what it is doing now.

When vehicle is started, it runs with the same slight miss it has always had for approximately 3 minutes with no issues at all. After that it's back to the original issues with no DTC's. Your Ideas??? I'm thinking maybe a fuel pressure regulator stuck open.

 

[Albino 94LTD]

Reset the ECM by disconnecting the battery for at least 10 minutes while you clean the Mass Airflow Sensor.

Make sure there aren't any vacuum leaks

 

[Byron Hillegas]

I took care of all of the vacuum leaks when I did the initial repairs. I'll be working out in the rain today. UGH! Let you know if resetting the ECM & cleaning the MAF works. Thanks for the input!

 

[gmanpaint]

If the fuel regulator is bad, fuel will be introduced into the vac tree and out the exhaust. Some will also get into the crank case, and you might be able to smell it mixed in with the oil.

Pull the fuel regulator vac line at the tree, and see if fuel is present. Then check the vac routing from the tree to the regulator. It is a sneaky jerk with the routing behind the engine, and around the intake, following the fuel rail. I mention this because you stated you changed the intake gasket. It could have easily come off, and is hard to see.

 

[Byron Hillegas]

Cleaned the MAF, replaced the air filter & reset the ECM with no luck.

The truck is using approximately 1/4 tank of gas in 7 miles.

On the fuel pressure regulator, should it not cut the fuel flow off if the vacuum line is removed? I found the vacuum connector swollen & what seemed to be oily & the nipple on the regulator was also oily I assumed from her leaky valve cover gaskets, but the line was NOT ATTACHED to the regulator. The truck runs the same whether the vacuum line is connected or not. I even attached a temporary line to see if the old one may have some unseen damage & had the same result.

 

[gmanpaint]

No, it will not shut off the fuel. If the regulator is bad, It will dump fuel into the engine thru the exhaust. You won't notice any change in how the engine runs, but you will see a dramatic loss of fuel. With the vac line off, it will dump more fuel then needed. 1/4 tank in 7 miles is an alarming rate of loss to me. I have seen drops of MPG cut in half, but nothing that severe with the vac line off.

I would install a New vac line, and change the oil. The Cat might be contaminated as well. If the problem persists, change the regulator.

 

[Byron Hillegas]

OK. I'll give that a try today. I'll let you know how it does. Thanks!

 

[Maniak]

Just some extra info/anecdotal evidence...

The Vacuum line is used to change the fuel pressure by a few PSI. When there is vacuum (typical 18"-21") the fuel pressure is reduced to the low 30's. When vacuum is removed (e.g. heavy acceleration) the fuel pressure is increased to the upper 30's.

Now, for the anecdotal part... Soon after rebuilding the motor in our X I noticed it would kinda lope at idle after a long drive (say 30 miles on the freeway) and I was getting crap fuel mileage. I was trying to figure it out when one day while it was loping I got out of the vehicle (I was at the house) and noticed black smoke coming from the exhaust. I grabbed my fuel pressure tester and found out my regulator wasn't exactly regulating. I had about 50+ psi of fuel pressure. I had no fuel coming out the vacuum port on the FPR so it never occurred to me that my FPR was bad, but it was..

Now, I was not getting anywhere near 2 mpg like you are (7 miles in 5 gallons) but I was getting about 10 MPG.

Maybe that'll help some....

~Mark

 

[Sedition]

That "black juice" out the exhaust should be a 'clear juice' when the exhaust is cold. I'd say your running rich. It could be your coolant temp sensor, or maybe a stuck open injector?

 

[Byron Hillegas]

I have 31 psi on fuel pressure. I'll be changing $465.00 worth of fuel injectors this weekend I guess.

 

[FR-425]

Leaky injectors usually doesn't require replacement just a clean up and new o-rings.

The rebuild kits are cheap and easy to find on the ol' eBay

 

[2stroke]

I doubt that you are going to have all the injectors fail at once. You would have seen it when you changed the spark plugs. One would have been black, while the rest would be white. Any chance that the timing is retarded? Has anyone done work to the timing chain recently?

 

[natenkiki2004]

31 PSI isn't bad really, depends on if that's with the engine running. Could be a slightly leaky regulator.

Also, $465 for injectors? No no no. I just bought a set of reconditioned ones for $100 and since yours is a 1993, I wouldn't bother with that.

 

[Byron Hillegas]

Timing? The whole truck is retarded. LOL! She has been without a vehicle for a week now. and has medical issues. I work 45 minutes away. She needs this truck back up & running. I don't have the time to wait for something to ship. Wish I did. Tearing back into it tonight. Took tomorrow off of work to get it done. I would chance rebuild kits or replacing only the bad ones, but with the poor maintenance that has been done on this truck up till now, I don't want to be doing this again in a week. I still have transmission issues & an automatic 4WD shift motor issue to deal with plus a head liner & door panels. I would have just bought her something else, but it has sentimental value to her, so it will be fixed. Stay tuned tomorrow, as I buy more stock in..."the dreaded auto parts store".

 

[FR-425]

You can get the rebuild kit at your local AP, it's not application specific. (at least not as far as the o-ring kits)

There pretty common generic injector used in a wide range of engines.

And their pretty bullet-proof, many-a-Ex run 200k + with no injector issues. Including mine.

Don't run'em daily or let it sit dry for a year, that's a different story.

 

[Byron Hillegas]

Okay. I replaced the injectors. Mine were beyond filthy. Picked Up a decent set at a local salvage yard, cleaned em up, replaced the O-rings, checked em out, put em in and I still have the same problem. I did however discover that If I unplug the MAF that the truck runs a lot better. With the MAF unplugged, the truck runs with only a slight miss, however after a few minutes, the engine will load up & smoke a little & run rough until you give it some gas to clear it out. Runs & drives fin going down the road. Plug the MAF back in & within a minute or so, it will run rough & smoke like a freight train. I have tried (4) different MAF sensors from the salvage yard. What are the odds that this is a ECM issue & where is it located on a 1993 Explorer?

 

[FR-425]

What color is the smoke?

 

[gmanpaint]

What codes are you getting?

With the maf disconnected, the ecm will automatically put it into a factory setting, and trigger a code.

If any sensor is faulty, a code will come up.

Vacuum leaks will throw ho2 codes on one or both banks., or EGR related codes.

Get the codes and post them for others to help diagnose, before you buy more parts.

 

[fritz24]

If you got a scantool can you show the short term fuel trim and long term fuel trim while the car is idling and on operating temp. This we can narrow down your problem rather than guessing what could be the culprit. Remember the value of the LTFT+/-20. increase the rpm to 1500 check the value if it will drop or increase depending on the value. Then increase the rpm to 2500 again check the value. Report back whatever value you have.

 

[Albino 94LTD]

If you got a scantool can you show the short term fuel trim and long term fuel trim while the car is idling and on operating temp. This we can narrow down your problem rather than guessing what could be the culprit. Remember the value of the LTFT+/-20. increase the rpm to 1500 check the value if it will drop or increase depending on the value. Then increase the rpm to 2500 again check the value. Report back whatever value you have.

A 1993 X is OBD1 and I'm pretty sure it can't do that.