Oxygen sensor bad?

[mikeinri]

No worries, Gary. Sometimes, in trying to be brief, it's tough to not sound gruff...

Thanks for the longer version of the story, sounds like "something" you replaced was due (since you've had some measurable improvement). A few things jump out to me, maybe they'll help you.

For future reference, always check the codes first. Usually, that will save you time.

The videotape idea is BRILLIANT!!! When I pull codes, I set my reader to beep, and I sit in the truck and watch the CEL while listening to the beeping (this probably only works in a quiet garage). I always run each test at least 2-3 times to confirm my work.

Never thought of taping it, that's a phenomenal idea. Could probably do it with just an audio tape recorder for those of us without video recorders. Really wish I had thought of that sooner. Once again, too simple for me to be obvious...

Onto the O2 code. Since it's showing up on KOEO, it's most likely electrical. Meaning, the fault exists while the engine is not running. Check the wiring, connectors and the O2 sensor itself.

Also, since your O2 issue is just on one side, that DOES raise the probability that it actually IS the O2 sensor (or its wiring). Typically, if an upstream sensor is the culprit, both O2 sensors will give bad readings. Of course, it could still be something just on the right side of the motor, but at this point, I would investigate the O2 sensor and its wiring.

If, after investigating the O2 sensor, you're still concerned about cleaning the MAF, go ahead and replace it. You can pull the sensor part off the rest of the housing, which is much cheaper to replace than the whole assembly. Especially since you've had a K&N in there, and a filter box sealing issue, I'd say you're a prime candidate to clean or replace the MAF.

There are other posts here that raise concerns about the oil required for the K&N filters messing with the MAFs. It comes down to personal preference, the K&Ns have pros and cons. If you decide you really want one, just realize that your MAF may need more attention from time to time.

Good luck, keep us posted, and stay warm up there!

BTW, outstanding diagnostic process just posted, glfrederick. Wow, if we all could be so disciplined. I wish I lived in KY, I'd just bring my Explorer to you! (This, for the record is not sarcasm...)

Mike

 

[greyboxer]

Thanks Mike, and Glfrederick you both have given me a lot of food for thought. But I gotta say I resent the both of you because now my nice mellow Sunday afternoon sittin' around doing nothing will instead be spent in the garage. Seriously though, awesome feedback from both of you and I'm looking forward to getting out there and putting it to use. I'll post again with the results. Stay tuned...(pun not intended, but it seems fitting eh?)

Gary

 

[glfredrick]

Thanks guys...

I'm not even working in the field of automotive repair right now -- just stuff I've learned over the years as a master tech and a Snappy dealer (where I got to take THOUSANDS of $$$$ worth of training classes for free...)

The discipline has served me well over the years -- going in it always frustrates others working around me, but in the end, I find the problem, FIX it (instead of swapping parts and praying) and most often beat the other guy in doing so. This is especially helpful when you run into the sticky problems that are difficult to diagnose.

As a for instance, while I was peddling Snap On tools, one of my customers had a late model Chevy truck. The complaint was that every time you stepped on the brakes it locked up the steering. Sounds mechanical -- right? That's exactly what the "pros" thought. They replaced the entire steering gear, including the box, the entire front brake system, including the master cylinder, and it still did the same thing. They were into this truck for thousands that they could not sell to the customer. -- Of course, I'm standing there thinking, "there goes my tool payment for this week, and likely the next couple..." so I jump in to help (which I rarely did at my customer's shops - bad ju-ju for the tool salesman to be better at fixing cars than the techs...).

I said that on the late model Chevys (and some others) there is a computer link between the steering and brakes that can only be fixed with a PCM flash. They just laughed. Then spent some more money... I came back the next week -- truck was still there -- same problem. My advice was the same. This time they cursed me, so I left. Came back the next week - same truck, still not fixed. This time they listened, hooked up one of my new Modis testers onto the steering and braking systems at the same time, did a split screen scope and hit the brakes... Of course, the steering psi spiked through the roof... Like I said, an electronic link between the brakes and steering on late model Chevys...

They had never heard of such a thing (who has, but "drive by wire" is a reality these days!) and after a PCM flash, all was well and the truck went down the road. I also sold them a $7500 Modis and $1500 a pop training for the entire shop. They had double that into the truck by then, and they learned their lesson.

As stuff gets more complicated, you just cannot shortcut the diagnosis process, for the computer can compensate for almost anything and make it look like almost any other thing.

Perhaps one day, I'll scan in some of my manuals...

 

[mikeinri]

You know, I've been thinking a lot about that lately.

Most of the codes I've gotten recently (maybe ever) on my 94 Explorer have been what I call "nuisance" codes, namely, the sensor dies or some vaccuum line that has no other purpose but to feed one of these sensors breaks or leaks.

Are we really better off with all these sensors and computers? What was so wrong with the way cars and motors used to be built and controlled???

I think I'd be seriously interested in a modification that eliminated all the computer crap on this motor.

Of course, it has run pretty well for 263,000 plus miles, so I guess I shouldn't be too upset. It's just that I can't believe that the motor wouldn't have done that without the computer. And I could really do without all the nuisance (and expensive) sensor repairs...

Mike

 

[glfredrick]

You know, I've been thinking a lot about that lately.

Most of the codes I've gotten recently (maybe ever) on my 94 Explorer have been what I call "nuisance" codes, namely, the sensor dies or some vacuum line that has no other purpose but to feed one of these sensors breaks or leaks.

Are we really better off with all these sensors and computers? What was so wrong with the way cars and motors used to be built and controlled???

I think I'd be seriously interested in a modification that eliminated all the computer crap on this motor.
Mike

No, No, No, No... You don't want to do that! You would quickly find that your engine doesn't run well, your transmission doesn't shift at all, and most of the other electrical items on your truck fail to function at all...

The computer-managed engine and transmission is a good thing -- not a nuisance or hindrance to high performance or drivability. I'm guessing that you are fairly young, and never had to deal with cars that still ran mechanical engine controls like points, carbs, linkages, etc. They were CONSTANTLY needing repair. There was a time when a person didn't go off without having a spare set of plugs and points -- and the tools and know how to fix them when they quit. Plugs were changed once a year -- not once in 100,000 miles. Heck, it was a rare engine that actually got to 100 K on the odometer! Carbs leaked... Cars stalled... They didn't start when it was cold outside...

People were constantly fiddling with them to "tune them up" a term that we still use, but that has an entirely different connotation that in an earlier day when it was necessary just to make an engine start!

Yes, we require a few new tools to diagnose and repair our newer vehicles with engine management, but they are actually a huge blessing compared to what was... I've been there and I like what we have now...

Pushing 1 HP per cubic inch (or more!) is now commonplace, plus we actually get good mileage out of those type vehicles. Plus that car will just start up with a turn of the key, run almost silently, and put barely any emissions into the atmosphere. Back in the day, the first factory car to do that was the Corvette with a dual-carb engine that was a nighmare to tune. It would get 5-6 mpg, run like crazy on a good day (but would not outrun a new Honda Civic!).

Better to take some time to actually learn what all those "nuisance parts" actually are and what they do - the mystery then goes away and you will know how to diagnose properly.

I highly recommend (for our Ford products) this book:

http://www.amazon.com/gp/product/0837603013/104-7397963-7318362

After reading it, and spending some time under your hood, poking around with book in hand, you will have a great understanding of how things actually work.

 

[IFLY]

Occassional Rough Idle, and/or knocks on acceleration

Hi

As a first time user of this site, I am happy to see so many good ideas and information.

I have a 94 explorer with 160,000 miles on it with similar problems. Except, my mileage is around 16 to 17 mpg.

I too ran the codes, and came up with EGR problems..I changed all the EGR components, and plugged everything back in..same problem. Checked vac hoses..

Ended up taking it to the Ford garage..not a good plan..they changed the MAF, installed new intake gaskets and said all was fine..all the the pittance of $800.00.

Guess what.. same problem still exists. I called one of Fords lead techies, and he told me that it was a gasoline problem..maybe pull the heads and clean them up?

What do you folks think?

Thanks

Randy

 

[Positive Vibes]

Hi

As a first time user of this site, I am happy to see so many good ideas and information.

I have a 94 explorer with 160,000 miles on it with similar problems. Except, my mileage is around 16 to 17 mpg.

I too ran the codes, and came up with EGR problems..I changed all the EGR components, and plugged everything back in..same problem. Checked vac hoses..

Ended up taking it to the Ford garage..not a good plan..they changed the MAF, installed new intake gaskets and said all was fine..all the the pittance of $800.00.

Guess what.. same problem still exists. I called one of Fords lead techies, and he told me that it was a gasoline problem..maybe pull the heads and clean them up?

What do you folks think?

Thanks

Randy

Sounds like a typical stealership response! Just throw money and parts at it!

"A gasoline problem"?????????????????????????? Can they be any more vague???

First off start a new thread for your X and post the exact codes that you pulled and post them. Nest post what has been done, maintanence wise and then we can help.

 

[IFLY]

Thanks. When I get back in town, I will start the new thread.
Randy

 

[mikeinri]

Hey glfrederick,

LOL, I'm not sure if I'm young anymore, pushing 40 soon...

I DO remember the old cars. For starters, there was actually enough room in the engine bays to work in there! Not only because the front ends tended to be longer, but there wasn't all the emissions, sensors, etc. that we have to deal with today.

While I do recall working with my dad to fix carb leaks, timing issues, etc., we had several cars that made it past 100,000. I think with fuel injection and solid state ignition (as opposed to points), most of the old problems would go away. I still don't see the need for all the other sensors.

I'm sure that book you posted is excellent at describing HOW the setup that we now have works, but I still don't think we HAVE to have it...

And, your quote of my post conveniently left out that I did acknowledge that I am amazed at the longevity of this engine (264,000 miles now)...

Funny thing is, when I posted this, I almost expected someone to have the opposite reaction, thinking I was old and looking back at the "good old days."

Mike

 

[Explorer93RDB]

Well I am having the EFI Blues. but, I want to learn this well.. b ecauase I would like a Fuel Ratio of 14 to 1 consistantly. try that with your carbed engine. and One wire going to the coil.. I am setting up a 5.0 to put in my Ex someday. and will run the Computer and all the sensors....

 

[glfredrick]

Hey glfrederick,

LOL, I'm not sure if I'm young anymore, pushing 40 soon...

And, your quote of my post conveniently left out that I did acknowledge that I am amazed at the longevity of this engine (264,000 miles now)...

Funny thing is, when I posted this, I almost expected someone to have the opposite reaction, thinking I was old and looking back at the "good old days."

Mike

I didn't intend any insult...

The reason I figured that you never ran much of the old-school stuff is that it was actually a real pain. Are our engines "over-sensored" probably, but you can run almost any fuel in them that will burn and they will trot right down the road. Knock sensors, temprature sensors, mass air flow, oxygen, engine vacuum, etc., all fed into a computer that checks things multiple thousands of times a minute and you end up with a mechanic in a box for the most part.

Back when I was running my Chevelle, I had to carry spare points, condensor, a set of plugs, carb tuning tools, and a few other things if I wanted to make sure it would get me home. I could always tell when the points were going down - instead of my normal 7800 rpm red-line, I could barely pull 5000. After that, it would start coughing and choking, soon to die.

Just throw some bad gas in that baby and it was death warmed over. It would rattle so bad that it sounded like I had a broken piston. Of course, when you're pushing 12:1 compression, that happens. Oh, and it averaged 4 mpg when I was taking it easy. Get on it and it was sort of how many gallons per mile. I often filled that car up 3 times a night when I was out cruzin' (slang for that evil, nasty habit of street racing...).

Then, the factories started to attempt generation one emissions controls. You want to talk about vacuum line and controller heaven... Ever realize that there are virtually no mid 80s cars left on the road anywhere? They were the suck in a big way. They had somewhere around 3 miles of vacuum hoses -- most connected to each other after you traced the system -- all designed to fool some testing equipment into believing that they were no longer poluting the air. Ha! Then, there were those wonderful electronically-controlled carbs. They are still on Jeeps up until the early 90s (and 2 of my kids work in off-road shops... :thumbdwn: ). the only fix for them was spending $600 on a new one.

No, for me, the electronic stuff is a marvel, and a blessing from God. We get 300 + HP that we can drive to the grocery store all day long, and pull down mid 20s in mpg while doing it, and that on gas that is mostly corn lik'r...