O2 sensors

I need to replace an O2 sensor, on a '97 Astro. Would you believe that there's 4 of them?
Since the after market ones are so much cheaper, I was wondering if they're as good as originals
Bosh is on a sale now, so any comments on them would be appreciated.
Thanks

I don't think I've ever bought an OEM O2 sensor.
In my opinion, Bosch makes pretty good parts. If they're on sale I'd be on that like a duck on a june bug.

Last time I bought a new "AC-Delco" sensor, at least that's what the bag said.... The sensor itself was stampted BOSCH.

Thanks Guys
Kings, just an FYI; years ago a bought the recommended Bosh Platinum plug for an old car of mine, figuring that by the time the plugs were shot, the car would be too. Less than a year later, the car started smoking bad. I pulled the plugs to find that 2 plugs had dropped their insulators into the engine. I put the old plugs in, and had to add that "no-smoke" syrup to the oil until the car went to the wreckers.

Thanks Guys
Kings, just an FYI; years ago a bought the recommended Bosh Platinum plug for an old car of mine, figuring that by the time the plugs were shot, the car would be too. Less than a year later, the car started smoking bad. I pulled the plugs to find that 2 plugs had dropped their insulators into the engine. I put the old plugs in, and had to add that "no-smoke" syrup to the oil until the car went to the wreckers.

Big 10-4 on the bosch plugs

On Bosch 02 sensors The aftermarket OEM type usually work ok.
And bosch makes a lot of factory OEM sensors.
Just do not use the universal fit all splice on wire in jobs.

But are you sure you need 1 or all 4 o2 sensors or any o2 sensors.
Just like cats 02 sensors last a long time and very seldom go bad unless someting is causing them to.
Are you getting any codes or bad 02 sensor readings?
And remember even if you have a code it does not say to replace the sensor it says check it out.
MT

Thanks for the advice.
I forget the code, but it translated to "no response, sensor 1, bank 1", if I remember correctly. There are no other codes.
I haven't checked the connector yet, (too cold), but I interpret this as the one in the drivers side "Y" of the cross-over pipe. It's got 4 wires on it, which I assume means it's a preheated one.
Since it's on sale at 20% off, I thought I'd pick it up and fix it later.
Any more thoughts are welcome

Well one other thought is to check the wiring to make sure none of the insulation is chafed or burned. O2 sensors will last a long time. My jeep still has the OEM after 160K miles.
The sensor itself typically doesn't fail, but they can get clogged up with carbon, and from what I've read they can't really be cleaned. Of course, this could be dealer service propaganda though. If I recall, you have a digital multimeter, you might read up on testing the O2 sensor and see what output you are getting.

I can't speak to the bosch plugs, never bought one. Discussions about plugs are like discussions about oil filters and and synthetic versus hydrocarbon oil. I've bought "higher performance" plugs before and never could tell any difference. I typically buy an OEM equivilant champion, AC Delco, etc. etc.
But since you mentioned your not so good experience with Bosch, I think I'll not be buying any of those.
O2 sensors aren't real cheap parts even on sale. You might just pull it and take a look at it before you drop the change.
happy wrenching.

I did check for anything odd, but no luck. I cleared the code, and it came back.
I warmed the engine, and took a gas-line wrench to it, and broke the wrench. While driving for a new wrench, I passed the place where I bought the van. I asked if they could change the sensor, and they said bring it in. They used a torch, and just an open end wrench. I went to pay, and they said they'll get me next time. And then I found out my broken wrench has a lifetime warrantee.
And the van passed its emission test.

Sometimes the planets just line up right.
Ya should'a bought a lotto ticket, sounds like your good luck was running deep.

That O2 sensor must've really been corroded.

Just for anyone interested.
You can revive an O2 sensor sometimes. You will need to heat up the sensor tip with a torch. You will need a MAP tourch as a Propane one will not get hot enough. Using the tourch you heat the end up enough to burn the carbon off. As already stated they usually last a long time and just get carbon in them. O2 sensors work using a crystal that conducts electricity when in an oxygen atmoshpere. If the crystal gets coated in carbon and soot then it is not exposed to oxygen (or not as much in the case of one not quite dead one).

Just for anyone interested.
You can revive an O2 sensor sometimes. You will need to heat up the sensor tip with a torch. You will need a MAP tourch as a Propane one will not get hot enough. Using the tourch you heat the end up enough to burn the carbon off. As already stated they usually last a long time and just get carbon in them. O2 sensors work using a crystal that conducts electricity when in an oxygen atmoshpere. If the crystal gets coated in carbon and soot then it is not exposed to oxygen (or not as much in the case of one not quite dead one).

They also have a vent hole in them that stops up and will kill the sensor to.
MT

In my '89 astro, I have replaced one AC Delco, Bad since installation, a second AC Delco, Good!!, lowered gas consuption, but, after 23,000 miles I had to replace it 'cause gas consuption increased, I Installed a BOSCH PREMIUM, 'till now It has 18,000 with no problems an excellent (the best) gas consuption and power.

I am getting a trouble code of P0420 - "Catalyst system under threshold bank 1" or something like that. Its a '97 with 112,000 miles. Is it the catalytic converter or just the sensor downstream of the catalytic converter or mabye both?

Any help would be appreciated!

Jim

:banghead:

"Bank 1" is the bank with cylinder #1 in it. (drivers side)
you've got 4- O2 sensors: 1 in each bank, 1 ahead of the cat, 1 behind the cat.
I'd say it's the 1 in the exhaust pipe on the drivers side.
That's the 1 that quit in my van.
You've got a reader? Why not unplug them 1 at a time to check?

I am getting a trouble code of P0420 - "Catalyst system under threshold bank 1" or something like that. Its a '97 with 112,000 miles. Is it the catalytic converter or just the sensor downstream of the catalytic converter or mabye both?

Any help would be appreciated!

Jim

:banghead:

You really need to start a new post on it but here is some info.
At this link.
http://www.troublecodes.net/articles/catfailure/

Also more info.

DTC P0420, P0421, P0430 & P0431: Check Possible Cause Of Misfire DTC P0420 and P0421 indicates bank one catalyst system efficiency is minimum requirement. DTC P0430 and P0430 indicates bank 2 catalyst system efficiency is minimum requirement. Possible causes are as follows: Use of leaded fuel. Oil contamination. Cylinder misfire. Fuel pressure too high. HO2S sensor improperly connected. Damaged exhaust system component. Faulty ECT sensor. Faulty HO2S. Ensure ignition timing is correct. Retrieve all Continuous Memory DTCs. If misfire code(s) is not present, go to next step. If misfire code(s) is present, isolate cylinder and repair as necessary. Check HO2S Monitor DTCs If DTCs P0136, P0138, P0140, P0141, P0156, P0158, P0160, or P0161 were present in step 1), service as necessary before continuing. If none of these codes are present in step 1), go to next step. Check ECT Sensor DTCs If DTCs P0117, P0118, P0125 or P1117 were present in step 1), service as necessary before continuing. If none of these codes are present in step 1), go to next step. If any codes except P0420, P0421, P0430 and/or P0430 were present in step 1), service as necessary before continuing. If no codes except P0420 and/or P0430 were present in step 1), go to next step. Check Rear HO2S Wiring Harness Turn ignition off. Ensure HO2S wiring harness is correctly routed and connectors are tight. Repair or replace as necessary. If wiring harness and connectors are okay, go to next step. Check Fuel Pressure Turn ignition off. Release fuel pressure. Install fuel pressure gauge. Start engine and allow to idle. Note fuel pressure gauge reading. Increase engine speed to 2500 RPM and maintain for one minute. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to CIRCUIT TEST HC . Check For Exhaust System Leaks If exhaust system leaks, it may cause catalyst monitor efficiency test to fail. Inspect exhaust system for cracks, loose connections or punctures. Repair or replace as necessary. If exhaust system is okay, go to next step. Check For Exhaust System Restrictions Inspect exhaust system for collapsed areas, dents or excessive bending. Repair or replace as necessary. If exhaust system is okay, go to next step. Ć Check Manifold Vacuum Install tachometer. Connect vacuum gauge to intake manifold vacuum source. Start engine and raise engine speed to 2000 RPM. Manifold vacuum should rise to more than 16 in. Hg. If manifold vacuum is okay, go to next step. If manifold vacuum is low, go to step 11). Leave tachometer and vacuum gauge connected. Start engine and raise engine speed to 2000 RPM. On a non- restricted system, manifold vacuum should quickly rise to normal range as increased RPM is maintained. On a restricted system, manifold vacuum will slowly rise to normal range as increased RPM is maintained. If manifold vacuum is okay, no indication of exhaust leak or restriction has been detected and testing is complete. If manifold vacuum is low or slow to respond, go to next step. Leave tachometer and vacuum gauge connected. Remove exhaust pipe from exhaust manifold. Start engineand raise engine speed to 2000 RPM. If manifold vacuum is now okay, fault is downstream from exhaust manifold. Reconnect exhaust pipe to exhaust manifold and go to next step. If manifold vacuum is still low or slow to respond, fault is in exhaust manifold or intake manifold gasket. Repair or replace as necessary and repeat QUICK TEST. Leave tachometer and vacuum gauge connected. Disconnect muffler/tailpipe assembly from rear of catalytic converter. Start engine and raise engine speed to 2000 RPM. If manifold vacuum is now okay, fault is in muffler/tailpipe assembly. Repair or replace as necessary and test drive vehicle to verify elimination of symptom. If manifold vacuum is still not okay, fault is in catalytic converter. Repair or replace as necessary. Check tailpipe/muffler assembly for debris from catalytic converter. Test drive vehicle to verify elimination of symptom.

Start a new post and let us know how it goes.
MT

I am getting a trouble code of P0420 - "Catalyst system under threshold bank 1" or something like that. Its a '97 with 112,000 miles. Is it the catalytic converter or just the sensor downstream of the catalytic converter or mabye both?

Any help would be appreciated!

Jim

:banghead:

Also any time you get a cat code always make sure the tune up is up to par.
How is your tune up end? Plugs filter and soo on?
MT