Question Asked: After about 30 sec, chugs, loses power, Check Engine Light on; only 2 cylinders
March 04, 2014, 12:27 PM
Still trying to get my 1992 Ford Explorer 4.0L 4dr Auto 4WD VIN X to run properly.
Here's the current situation:
It starts fine, runs about 30 seconds, then chugs, loses power, and Check Engine Light comes on.
What we've discovered: It is running on only 2 cylinders now. When I pull the the wires off the coil, here's what I find: Cylinders 1 and 5 do not spark at all. Cylinders 2 and 6 spark but do not fire. Cylinders 3 and 4 spark and fire.
When I first got this Explorer, the engine ran fine. These problems occurred after it failed a smog test. (It probably would not have failed had anyone noticed that a 1' piece of tailpipe was missing between the catalytic converter and the exhaust pipe, which I've since installed). After making many attempts, codes were pulled but were random so I replaced O2 sensor, crankshaft position sensor, MAF, cleaned the Idle adjust sensor, replaced vacuum tubes, repaired a few broken ground wires, re-installed the 'retard timing' octane jumper.
I base the cylinder numbers on this diagram:
3 4 -- sparking and firing
2 6 -- sparking, not firing
1 5 -- no sparking, no firing
(Coil looking from the front)
Cylinders on the engine are numbered
Question Asked: Vacuum line needs plugging in, but where?
February 06, 2014, 07:36 PM
My 1992 Ford Explorer XLT 4dr 4wd Auto 4.0 V6 has begun suddenly running rough and the check engine light comes on. It happened after I replaced the O2 sensor, when I was reaching behind the engine to get the O2 sensor wiring, and ended up pulling up that AND a vacuum tube from alongside the transmission fluid tube.
Here are links to pictures. I cannot find where this vacuum tube should be plugged in. Does anyone recognize it and have suggestions about where it should be connected?
Question Asked: After changing O2 sensor, car eventually (15 mins?) quits running smoothly
February 06, 2014, 05:30 PM
Took my 1992 Ford Explorer XLT (4-door, auto 4WD, auto tran, 4.0 V6) for smog test (California) and it failed. It seemed to run fine, and indeed everything passed EXCEPT "NO (PPM)" -- Max 699, measured 2342! So, it's a "GROSS POLLUTER." (I now suspect this was caused by an unoticed missing 8" "intermediate" pipe in the exhaust system.)
I'm over a barrel (very broke, NEED to get the Ford running and licensed), so the tech suggested it probably is a bad Oxygen Sensor (the primary one, before the catalytic converter). I coughed up the $50 for a new one and replaced it.
After replacement, as always, the Ford ran fine ... until about 15 minutes later, while driving. Suddenly, a clunk, power drops, engine runs rough and smells of fuel, and the "check engine" light comes on. I nursed it home.
The next morning, I try the Ford again. It starts, runs okay, then after about 15 minutes of idling, the same bad thing happens: sudden clunk, power loss, rough running, fuel smell, 'check engine' light.
I then re-installed the original oxygen sensor, hoping to solve the problem.
Now the same problem, after another day: it starts, runs, then after a few minutes, loses power, check engine light comes on, it chugs and knocks.
Summary: I put in a new O2 sensor, and this problem began. I removed the new O2 sensor and put the original one back in, and the problem continues. BEFORE I changed any O2 sensor, the vehicle ran good and was reliable.
Anyone have any idea what I probably did wrong, and how to fix it? Could it have something to do with the computer not recognizing the sensor?