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Oxygen sensors, whats better...factory or aftermarket?

8K views 71 replies 12 participants last post by  2-manytoyzs 
#1 ·
You know what I mean, it seems the factory ones last a 100k but aftermarket seem to last 30-80k. Is it because the older the engine gets the more oil contaminates the sensor? Or is it because the factory ones are better made, they do have a slightly different design on the diffuser?

What do you think?
 
#2 ·
If the origional is BOSCH, you can save a lot by buying from a jobber. But I would check both sources for price first.

A lesson learned; I was working on a ASIAN and it needed a O2. I bought one from a jobber at a very high price but thought it was normal. Turned out it was a universal and you had to wire it into the harness. It was heated on top of that. I called the dealer and the OEM was half the price.
 
#4 ·
A jobber is a large parts supply house, not to be confused with AutoZone, PEP BOYS or anything of that nature.

The jobber I buy from here locally is a MOTORCRAFT and AC DELCO dealer that supplies to local dealers. They also carry top brand name replacement parts (not to be confused with CHI-COM)

The O2 sensor gives reading signals to the ECM/PCM so that it can control air/fuel ratio.
 
#5 ·
For Steve. Most likely, you need to replace the O2 sensor. Duals should not effect the A/F ratio, and most of the smog junk involves recirculating emmissions except for the Cats and gasoline fumes. Heated type O2 sensors are used mostly when the sensor is not located close enough to the exhaust header to keep temp above 600F. You will pay more for the heated type so make sure you know what you need before you buy. Also, if installing duals all the way, make sure you add the O2 bung as close to the exhaust dump as you can and still change out. This way you dont need the heater.

Trees
 
#6 ·
HEY 4 JAW: WE buy O2 Sensors and sell them with some of our equipment to the Heat Treat industry. We only buy OEM type because they have to meet standards that are set by the manufacturer. They are used in furnace applications at elevated temperatures, so they don't last long, but it gives a good test. We buy them in quantity from a local jobber who supplies dealers with factory parts at a discount. DAVE
 
#7 ·
...and don't forget some sensors have two heaters. ;)

Much of the problem of course is a O2 sensor here from Ford can be as much $100 and an aftermarket version could be $40 that needs to be wired in. When I have examined these side by side you can some differences in construction, like diffuser design and probe length with some models.

Seeing as all these things are basically is thermocouples you would think there would not be much to be different but I thought I would ask the opinion of the masses.

Since I bought this scanner running the DCL while driving has certainly been enlightening, not only did I find out my O2 sensors are malfunctioning but it only happens once they get good and hot, idling will not cause them to fail.

Now if only I could find a way of mounting this computer in my dash...perhaps some blue fluorescent lighting...disco ball maybe...fire extinguisher...I wonder if a wing would help? :p <img src="graemlins/drool.gif" border="0" alt="[drool]" />

[ March 18, 2003: Message edited by: 4 Jaw Chuck ]</p>
 
#9 ·
Simple test for O2 sensors. Warm up the eng to operating temp. For single wire sensors, disconnect the wire connector near the sensor. Connect the volt meter to sensor wire (coming from the sensor) and the other lead to ground. Leave the harness end disconnected. Set voltmeter to lowest scale. Start eng and run at 1500 rpm for about 2 min to warm up O2. I prefer a digital meter such as Fluke. If the O2 is operating properly, it will give a fluctuating reading of .1 to .9. Anything above .5 indicates rich, below indicates lean. The reading will cycle back and forth, rich and lean, at about 1 times per sec. If it takes more than 4 or 5 sec to change, that indicates a weak or slow sensor. If its not reading a voltage it has an open or shorted circuit. If its reading high (above .5) that more than likely means its running to rich to adjust itself, but more than likely the sensor is still good. If its low (below .5) or stuck low and not moving, it could be lean or sensor bad. A heated (HEGO) O2 is tested the same way. You just have to find the O2 output wire by probing the wires until you find one with the varying voltage, or better to find the correct wire with the wireing diag.
Tips ... Rev the engine if the reading is not changing or disconnec a vac hose to get it to run lean, or use a drip bottle to squirt gas in the vac hose to get it to run rich or disconnect the ect or act sensors. Do something like that to get it to run rich and lean to see of the sensor follows.
You can pick up a digital multimeter for less than the price of a pair of sensors at radio shack.
I had 200,000 miles on my tbird with the original sensors. As long as you dont contaminate the sensor and keep the eng running properly, the sensor should last a long time.
Chuck We had a laptop (at the dealership) that we took on the roadtests, connected thru the DCL (data communications link). You can see all the eng running parameters. That would be nice to have on my daily driver, but they are more distracting than a cell phone cuz you watching that all the time instead of the road. Its absolutly amazing to see whats going on in the computer. I really miss that part of working but to be retired is soooooooo much better!
 
#10 ·
:D I almost went on a few off road excursions myself scrolling through all the observable sensor signals while driving, thank God for the record function!

I'm just glad to physically see the sensor go bad and the check engine light confirm the episode, funny even a small voltage like .04 volts is enough to keep the light off but .02 volts will set the light. I continue to learn something new everyday. It certainly explains the weird fuel mileage I have seen lately, 40 bucks one week and then 20 the next?

Now if only I had purchased this tool back in 84 when I needed it to diagnose my 84 BroncoII, I hate throwing parts at a problem not knowing if I am going to fix it just going by the KOEO codes.
 
#11 ·
I know that if the O2 sensors are bad than you get horible gas milage. cruising 70 on a flat highway(rarely happens in Oklahoma) I get about 17 MPG (based on the electronic dealie in the dash) Anyone think that they are bad at 150,000 miles?If they were bad would it cause the motor to act odd?The O2 sensors are in the back of both exhaust manifolds so they SHOULD be easy to change, anyone have any idea how easy they are???? Steve
 
#13 ·
Hey Kultulz.

You know what I mean when I said that the O2 sensors are on the back of the exhaust manifold, right? How hard are they to change out? Get it a little warm and get a socket and a wrench and just start cranking with a cheater bar or do it cold with some WD40?The plug on the passenger side is easilly acessable but the driver side is a little harder to even see, I hope it isn't a pain to do. Steve
 
#14 ·
Yeah I know I'm a little late chiming in here but Steve they make a crowfoot style socket just for O2 sensors that I always use. It's way stronger than any wrench or standard crowfoot socket. I also would never use any O2 sensor that wasn't OE replacement part. Something about using a "willfit" part on something operating on less than 1 volt. You've already seen that just a tenth or two difference in the voltage the PCM sees could greatly affect your gas mileage but not neccessarily turn on your check engine light if she's within the accepted voltage range for the sensor. Most guys I work with feel the same way. Alternators, starters, etc., different story. Just my opinion. ;)
 
#15 ·
Well Autozone has Bosch, I checked and they are the same sensors that we had put on my wifes 94 eagle Vision, and they seemed to help, no more engine light. So should I get 'em at a Ford dealership? Or would they be more expensive?Also, I know about the socket, tried it on my wifes car and they didn't work, had to take them to a guy to put them on. Steve

[ March 18, 2003: Message edited by: 5.0Towncar ]</p>
 
#16 ·
The main thing is that it's not what I call a "willfit" part, meaning no wire cutting, crimping, etc. You want it to be a direct replacement. Unfortunately all tool makers are not the same. My Snap-On socket has been taking out O2 sensors for years for me no trouble (although I have had to heat a few for help). But I'm the guy who gets the car when the owner can't do it and I only own one Snap-On O2 sensor socket and it's all I've ever needed. But back to the original question, I would try and get Motorcraft O2 sensors Steve.
 
#18 ·
Unfortunately the Motorcraft sensors will no doubt be more (rough guess $80.00) but like I said I'm just a stickler with these things. If you try the Bosch just make sure it is direct fit not a universal fit. You probably just needed a little torch help with your other car. ;)
 
#19 ·
Ford has several manufacturers for thier O2 sensors. Bosch is one of Fords main suppliers of O2 sensors. Never had an problem with Bosch o2 sensors. Ive put in lots of 02 from boxes that had Bosch stampings on them.
Hey morris havent seen you on here for a while. Good to see you back.
 
#20 ·
Hey Duke, I have the Mitchell Manual CD set so I am good to go as far as documentation goes. I've found enough info on the specialty SHO sites that I feel like I have already taken it apart.

The starter died on Saturday so I spent Sunday rebuilding it, brushes were worn out but otherwise everything was kosher as far as wear goes. A new solenoid, bendix, and brush set plus a custom paint job by Chucky along with a complete lube of MolyKote should put her good for another 100K.

Hey DM! Good to hear your voice, I have heard in the racing fraternity "wifes tales" of how factory sensors respond quicker and hold a tighter voltage spectrum during operation. Of course this is a bunch of guys bench racing but after seeing them side by side they are slightly different. Who knows? I do like to keep the car as original as possible and a factory fit connector sure makes things easy. that Ford direct website gives basically the same price as what I can get here when you consider duty and shipping. $100 CDN.

Aftermarket Bosch are about $40-60 CDN here so it seems we are getting decent pricing. I'm going to look for data on the web to support this theory and post it on a couple engineering forums I'm on also.
I wonder if it really matters because when I watch the fuel trim for each bank during closed loop operation and during the period when the sensor goes out, it takes a few seconds for the mixture to change with fuel trim numbers going up 5% at a time. Obviously it's not instant reaction by the computer to adjust for the apparent lean condition so even if the sensors were slow to react the computer may even be slower. It might not matter?

We have our best men on the case... ;)
 
#21 ·
Looky...looky!

Should have known to ask the number one builder of O2 sensors in the world. The Heated Wide-Band O2 Sensors (LSU) seem to be what I want, looks like all I need to do is adapt the threaded portion if it is different.

This type appears to be backwards compatible! Perhaps a planar type?

[ March 19, 2003: Message edited by: 4 Jaw Chuck ]</p>
 
#22 ·
But I'm the guy who gets the car when the owner can't do it and I only own one Snap-On O2 sensor socket and it's all I've ever needed.<hr></blockquote>

A man is only as good as his tool... :D

BOSCH is the main supplier of O2 sensors. I would use it on an early TOWNCAR but would have to compare the two really carefully as far as a SHO goes. While the SHO sensor is made by BOSCH, it may be of such a design that they (BOSCH) don't or can't offer it directly to the public.

<a href="http://www.boschusa.com/AutoParts/OxygenSensors/" target="_blank">-BOSCH Oxygen Sensors-</a>

5.0 Towncar... Did you read 2-manytoyz post on how to check the sensor without a scan tool?
 
#23 ·
A new solenoid, bendix, and brush set...<hr></blockquote>

:eek:

BENDIX!? Did you say bendix? ...tsk...tsk...

If you are going to be the owner and driver of a fine FOMOCO automobile, you are going to have to get over those archaic stovebolt terminologies...

Proper FORD etiquette dictates the term Starter Drive for that particular part. :D

Have you done a search on CANADIAN FORD dealers that sale over the net? I keep forgetting you are one of those MOOSEHEAD drinkers... :D
 
#24 ·
Funny how the Bosch site lists the service interval on this part as 100K miles and this car has exactly 165 Kms, now thats engineering for ya!

I hear you there Duke, we wouldn't want anyone to inadvertantly confuse the inferior Chevy/Chrysler "bendix" to a high performance/quality Ford "starter drive". :p

I stand corrected. :D

One thing is for sure the car has so much more power now that I fixed the starter :rolleyes: . It must have been the yellow "High Voltage" sticker I put on with Japanese lettering after the rebuild...... <img src="graemlins/mwink.gif" border="0" alt="[mwink]" />

Just think if this is the kind of power increase I can get just rebuilding the starter just think what a wing would do...ummm...a bigger wing. :p <img src="graemlins/mwink.gif" border="0" alt="[mwink]" />
 
#25 ·
Thanks for the info, 2Manytoyz! Question, though, the manual for my heated snesors (??Did I just say "snesors??) says don't try to cut and splice wires as they are part of the sensor and it screws them up. Are GM sensors different from Ford? Also, I have 2 on each side...one just above the collector and one just behind the cat. Are these different? They have the same number of wires but different plugs.

Finally...what causes the sensors to foul? Is it oil or carbon or what?
 
#26 ·
Hey 4Jaw...if you're running the DCL into a laptop there must be a way to capture the data stream in a file so you can replay it later. Check your software and see what it says. That's probably safer than getting crosseyed trying to drive and watch the screen while you're calling your girlfriend on your cellfone! <img src="graemlins/nono.gif" border="0" alt="[nono]" />
 
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