Weird problem that went away - 92 Explorer

[Shran]

I took my Explorer on a 500 mile round trip last weekend. Halfway point was the campground we were staying at. Explorer ran great all the way down there, we stopped at the campground office and checked in. Came out 10 minutes later and it instantly had an awful miss and very strong raw gas smell. Drove it about 1/4 mile to our camp site, shut it off, started it again and it ran normally but was smoking a lot - if I cracked the throttle I'd get a huge puff of dark blue or black smoke.

Figured I was stuck there for two days anyway so I'd see what happens when I go to leave on Sunday. Started right up like nothing had ever happened and I drove it back home without any issues. No smoke, no miss, no excessive oil/fuel consumption.

Any idea what could have caused that? Best I have come up with was an injector stuck open when I parked at the office, filled up a cylinder or two full of fuel and fouled the plugs, and the smoke was just excess fuel burning off in the exhaust and it unstuck itself at some point.

 

[dvdswan]

Maybe an O2 sensor wire was shorting out then the wire shifted? It sounds like it was definitely running rich. So something along those lines is causing the issue. Intermittent ones are not fun to chase.

 

[09fx4guy]

It does sound like somehow it kept filling up with fuel, and the only thing I would think of is a bad injector (as you mentioned). Either the injector stuck open mechanically or electronically (not sure on that). Before you go crazy chasing it, I would stick with short trips around town and see if it happens again. If it does happen again, I would either clean out or replace the injectors, and while doing that, examine all of the wiring for them.

 

[Shran]

Yeah super rich. Why it cleared up and ran OK ever since is strange. It has always had kind of a rough idle for a few seconds on a warm start but not like this and it clears up right away, and doesn't smoke.

Drove it all over town yesterday and it was fine. I was kinda tempted to pull the plugs and examine them but I'm sure ~300 miles after the incident with no symptoms they will probably look OK.

I changed the oil right after I got back too and it was normal looking/smelling for oil that had been in there for 5000 miles. I was half expecting an oil/fuel mixture.

I don't get too worked up or upset about things like this, it's almost 30 years old after all and has taken me all over the southwestern US with virtually zero major issues...it deserves to be grumpy once in a while

 

[sgtsandman]

An injector could have temporarily gotten clogged and stuck it open. A little bit of varnish in the system that broke loose is all it would take.

 

[scotts90ranger]

Probably the entabulator to flux capacitor wire...

Sounds like a fluke, could be an issue with a random wire too like a signal wire to an injector, signal wire to the crank sensor or MAF, or like said above just something sticking an injector...

 

[Shran]

Well this came back with a vengeance yesterday. It's been randomly hesitating for just a split second at partial throttle/low speeds. I was going up a hill and it felt like I lost a couple cylinders. Awful rich exhaust smell and wouldn't start later at my house unless I held the accelerator to the floor while cranking.

I have to tear into the engine bay again to replace my AC condenser so I think I'm going to pull the injectors at the same time and have them cleaned.

 

[Shran]

Let it sit for three days and fired it up. Moderate miss, lots of smoke, terrible gas smell.

Tore into it this morning and found #3 injector dripping fuel. Had no fuel pressure after sitting overnight. Sending them all of for a rebuild.

This may explain a weird rough idle/warm start issue I've been chasing for a while.

 

[ryan]

It's funny, my buggy has been doing the same with new-ish injectors. I'm leaning towards bad gas right now

 

[Shran]

That's possible, I ran about 10 gallons of junkyard gas through a different vehicle one time and it was not good. Pinging was the main issue I had but it just didn't run right.

These injectors are definitely the originals. I considered replacing them with remans but the price to have mine cleaned and tested was about the same. I sent them off to a place in Idaho called Mr. Injector, we'll see what they come up with.

 

[ryan]

That's possible, I ran about 10 gallons of junkyard gas through a different vehicle one time and it was not good. Pinging was the main issue I had but it just didn't run right.

These injectors are definitely the originals. I considered replacing them with remans but the price to have mine cleaned and tested was about the same. I sent them off to a place in Idaho called Mr. Injector, we'll see what they come up with.

In my case it runs great when it's cold but as soon as it gets warm things go to hell, was spitting codes for the MAF and IAC and still had the issue after. Catch can was full of gas too, so I think it was going wide open then.

 

[Shran]

As I suspected one of them was stuck. One would stick open with pressure applied. The guy at Mr. Injector said they all cleaned up perfectly. Looking forward to seeing how it runs with this mess fixed, should have them back in a few days