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A Mechanic's Life - Tales From Under the Hood

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  • thecardoc3thecardoc3 Posts: 1,521
    What *IS* a reliable catalytic converter test?

    Check for any exhaust leaks upstream of the catalyst, and before the downstream O2 sensor. Check for any TSB's and confirm that the PCM has the most up to date software. Monitor vehicle operation while checking fuel trim corrections and engine load pids, and if nothing is found then you trust the PCM in the case of a P0420, P0430.
  • thecardoc3thecardoc3 Posts: 1,521
    A hacksaw, a straight piece of pipe, and a roll of "Tiger Paw (tm)" tape

    That's a lot of work and it could be all for naught. We pull an upstream O2 sensor and install a pressure gage when possible, or pull a spark plug and install the pressure transducer and do a snap throttle and read the exhaust backpressure that way.
  • thecardoc3thecardoc3 Posts: 1,521
    edited January 2013
    In a departure from what I usually talk about with my weekly radio show I'll be having a guest come in who is one of the directors for Pittsburgh's yearly auto show. Traditionally when involved in any of the local auto shows the last thing that they want to talk about is what it takes to (or is going to take to) service and repair the next generation of cars. Meanwhile, that's all I'm ever really focused on so I need some input on exactly what topics should be brought up. The hour long show that I do typically can have six phone calls, and they will take care of themselves, that can leave some twenty minutes for host conversation.

    If you were in my place, what are the questions that you would like to ask? Keep in mind that at this moment I'm not sure the guest will be aligned with any one manufacturer. That's something I need to check on this week, I'm inclined to expect that he is not going to be manufacturer specific. If there are some topics here in Edmunds that might make for good subject matter, how about a link?

    I will say one of the fun things about the auto show is how my listeners react to the ticket giveaways we did last weekend. Seems lots of people are excited about going to the auto show this year.
  • steverstever YooperlandPosts: 40,176
    edited January 2013
    When I went to the Detroit show a couple of years ago, I noticed that several manufacturers had "tech" displays of (mostly) engines and transmissions. Cut-aways or an assortment of shiny parts in a display case.

    My feeling was that these displays didn't get a lot of traffic and that besides looking the cars, people wanted to fool around with the video games and such. The "get your photo taken with a Fiat" exhibit was popular.

    Guess I'd be interested to learn if the demographics are getting any younger, and what displays really draw the people in.

    You may want to cross-post this over in 2013 Auto Show Season.

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  • andre1969andre1969 Posts: 21,906
    That's a lot of work and it could be all for naught.

    Oh, I just meant that as a joke. Plus, nowadays the emissions controls are so integral that if you pull something off, you probably make it run worse!

    Just out of curiosity, when did they start putting O2 sensors in cars? Would something as old as my '79 5th Ave, or '85 Silverado have one? Or did they go in as soon as they started using catalytic converters? I know my old '88 LeBaron had one, because when it failed (or rather, a wire running to it got burned), it triggered something and made the engine start over-revving, and even at idle, I think it was pulling about 2000 rpm.
  • texasestexases Posts: 5,536
    Wasn't Volvo's 'Lambda' sensor (1977) one of the first O2 sensor setups?
  • busirisbusiris Posts: 3,490
    In a departure from what I usually talk about with my weekly radio show I'll be having a guest come in who is one of the directors for Pittsburgh's yearly auto show. Traditionally when involved in any of the local auto shows the last thing that they want to talk about is what it takes to (or is going to take to) service and repair the next generation of cars. Meanwhile, that's all I'm ever really focused on so I need some input on exactly what topics should be brought up. The hour long show that I do typically can have six phone calls, and they will take care of themselves, that can leave some twenty minutes for host conversation.

    Here's my suggestion for a topic...

    While its related to the area you say your guests typically wish to avoid, how about asking where they see the repair techs coming from in the future (ie., what kind of educational backgrounds, training programs, etc.)? What places offer such an education? How do they feel the issue should be addressed? Are the manufacturers going to take over the training, or will they co-op with tech schools/universities to train new mechanics?

    Looks to me lie you could spend hours on the subject.
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,396
    I'm curious about what nanny technologies are likely to become more widespread in the next gen of cars, and how that might/will impact diagnostics and repair.

    For example, you have several makes with parallel parking programs that park the car for the driver. Subaru has its "eyesight" system that is supposed to warn the driver of lane departure, maintain following distances, etc. Traction control systems are getting more and more invasive and trying to compensate for the driver, etc.

    Of course all of this stuff is going to mean drivers in the future are even less competent at driving a vehicle than they are now, so keeping it functioning (or perhaps disabling it safely for those who still want to drive their own car) is going to be a big concern.
  • busirisbusiris Posts: 3,490
    BTW, is your show available over the Internet?

    Living in SC, I don't have much success picking up radio programs originating on-air in PA.

    I'd love to give your show a good "listening to"... I'm sure it is interesting!
  • thecardoc3thecardoc3 Posts: 1,521
    Oh, I just meant that as a joke.
    I figured that ;)

    Just out of curiosity, when did they start putting O2 sensors in cars?

    That's something that I haven't really thought about for a while. For the most part they got phased in over about a six year period. I will actually have to look it up to find out who was "first".

    http://en.wikipedia.org/wiki/Oxygen_sensor

    Well it looks like it was Saab and Volvo in '76. I remember the first one I saw was associated with the Ford Variable Venturi 7200 carburetor. GM had O2 sensors on a couple models in 79, and then in 80 1/2 they came out with the C4 system (computer controlled catalytic convertor).

    It was almost six years later that some of the last aisan cars finally had feedback controls, and it wasn't until 95 that they had scan tool communication. GM had that in 80 1/2.

    Now back to the wiki article. I scanned over it fast, it needs a re-write in number of places. The article states;

    The sensor does not actually measure oxygen concentration, but rather the difference between the amount of oxygen in the exhaust gas and the amount of oxygen in air.

    That is incorrect.

    Rich mixture causes an oxygen demand. This demand causes a voltage to build up, due to transportation of oxygen ions through the sensor layer. Lean mixture causes low voltage, since there is an oxygen excess.

    That part is correct.
  • thecardoc3thecardoc3 Posts: 1,521
    BTW, is your show available over the Internet

    No, but the subject has been discussed. It might be time to bring it up again.

    I'd love to give your show a good "listening to"... I'm sure it is interesting

    Wouldn't know, I've never heard it.. :) Seriously though the feedback is kinda funny, there are days where we don't get any calls and I just run through my list of topics that I pick in advance and they get really good feedback from people who just sit and listen to the show. Frankly I prefer when we get calls, then I can just be myself and talk to someone about cars.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,085
    >>BTW, is your show available over the Internet
    >No, but the subject has been discussed. It might be time to bring it up again.

    What station is the program aired on?
  • thecardoc3thecardoc3 Posts: 1,521
    OK, I posted over there.
  • thecardoc3thecardoc3 Posts: 1,521
    WBVP AM 1230 and WMBA AM 1460
  • kyfdxkyfdx Posts: 28,004
    7 am to 8 am, every Saturday morning?

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  • steverstever YooperlandPosts: 40,176
    edited January 2013
    They should be streaming their content on the net. I listen to net radio all day, even for my local stations.

    And if they streamed it, I could rip your show for listening at a reasonable hour. :shades:

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  • thecardoc3thecardoc3 Posts: 1,521
    Just about every one. If the teaching job has me out of town then they do a "best of" show.
  • thecardoc3thecardoc3 Posts: 1,521
    http://articles.ky3.com/2013-01-23/keyless-entry_36511769

    Any idea how to even start the diagnostics? :shades:
  • busirisbusiris Posts: 3,490
    Awwwww...

    Bummer, dude!
  • explorerx4explorerx4 Central CTPosts: 9,619
    Easy, secret government underground installation. :)
  • steverstever YooperlandPosts: 40,176
    Great, when I get a new car, I'll have to take some tinfoil off my hat and wrap it around the fob.

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  • srs_49srs_49 Posts: 1,394
    Any idea how to even start the diagnostics?

    1. Do the door locks work with the key FOB?
    2. Are these all factory installed remote start systems, or are some/all of them after market add ons?
  • steverstever YooperlandPosts: 40,176
    edited January 2013
    I'm wondering if the shopping carts or the aisles have some sort of built-in RFID tech to either track the carts when people steal them or to run digital ads in the cart as you push them down the aisle. Hm, maybe it's just the items in the cart that the store is trying to track with RFID transponders. Push button ignitions use RFID (really, a shorter range proximately card) to figure out that you are approaching your car.

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  • thecardoc3thecardoc3 Posts: 1,521
    Now that's funny.. :D
  • thecardoc3thecardoc3 Posts: 1,521
    1. Do the door locks work with the key FOB?

    No, in fact a lot of the people can't get into their cars at all.

    2. Are these all factory installed remote start systems, or are some/all of them after market add ons

    Factory systems.
  • thecardoc3thecardoc3 Posts: 1,521
    I'm wondering if the shopping carts or the aisles have some sort of built-in RFID tech to either track the carts when people steal them or to run digital ads in the cart as you push them down the aisle.

    Good thought, now how would you "prove it"? Then, how do you fix it if that is the case?
  • steverstever YooperlandPosts: 40,176
    If the frequencies are the same (or the store transponder is stepping on the one the cars use), you could dial back the power or move the transponder so the signal's not bleeding out into the parking lot.

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  • stickguystickguy Posts: 14,294
    it sounds like there is enough evidence now that the location is causing the problem. So you have 2 ways to go about diagnosing. 1 is try to get the car to tell you (though I would not be surprised if there was nothing to tell, since the car would think the fob was not there).

    so, like Steve said, you almost have to work from the other direction. When you have an active failure, systematically remove a possible source of interference, 1 at a time, until the fob works..

    if you can do that, maybe then you can reverse engineer a solution!

    2013 Acura RDX (wife's), 2007 Volvo S40 (when daughter lets me see it), 2000 Acura TL (formerly son's, now mine again), and new Jetta SE (son's first new car on his own dime!)

  • busirisbusiris Posts: 3,490
    edited January 2013
    About 10 years ago I was riding a Harley through the Alps. At the top of a pass we stopped in a small tavern (every pass in the Alps has a small eatery/tavern I think) that also had a large antenna array located behind it.

    Before we left, the waiter told us if we couldn't start our bikes, just roll them down the road a couple hundred meters and try again.

    Sure enough, he was right. We couldn't disarm the ignition lock via the key fob, but on a Harley, it can be done manually by entering a code through the blinker switches. One guy with us tried that and was able to start his bike before moving it. The rest of us just followed the waiter's suggestion.

    I have no idea what the antenna array was for or what it was transmitting.
  • srs_49srs_49 Posts: 1,394
    An antenna does not have to be transmitting on the same frequency as the key FOB to perhaps cause a problem. For example, assume the key FOB works at (say) 400 MHz, and a nearby cell tower works at 2.2 GHz, 5.5 times higher than the key FOB. Even if the receiver in the car has a filter at the front end that is only supposed to allow the key FOB's frequency in, those filters are not perfect. So some energy from the cell tower can make it's way to the receiver in the car. This could overload the receiver (saturate the front end) so that it does not "hear" the key FOB signal. This is sort of like trying to pick out one voice in a crowd.

    Another phenomenom that can occur is rectification. The cell tower's signal couples onto wiring or the key FOB receiver's antenna. It is then rectified (converted to direct current, DC) and the resultant DC bias can overwelm the front end of the receiver.

    Either case can be fixed simply by moving the vehicle out of range of the cell tower.
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