XPost: alt.home.repair   
   From: xenolith@optusnet.com.au   
      
   On 3/4/21 5:19 pm, Steve W. wrote:   
   > micky wrote:   
   >> Are my business assumptions correct?   
   >> I'm trying to get rid of some engine trouble codes, and I need to   
   >> install 2 or 4 oxygen sensors.   I know I can install one of them, and   
   >> if I find a place where I can jack up the car and work underneath, I can   
   >> probably do the remaining 2 or 3. I'd prefer to do it myself mostly for   
   >> the satisfaction and bragging rights, but also to save money.   
   >>   
   >> However if I fail with 2 or 3 of them, I would take them to a shop to be   
   >> installed.   
   >> For no special reason except that I think I know how the world works,   
   >> I've always felt that if I buy parts and bring them to a shop to be   
   >> installed, the owner will make up the loss in profits on selling the   
   >> parts with an increased charge for labor, or something, on the theory   
   >> that the job takes the same amount of time minus 10 minutes to order the   
   >> parts, and he shouldn't be deprived of the normal income.   
   >> Is this true?   
   >> Is there a difference if the shop's owner has a reputation for being   
   >> honest?   
   >> Or do honest shops just charge the flat rate for the job and skip the   
   >> profit they would have made on the parts?   
   >> If I were in their shoes and I felt obliged to do that, I would be irked   
   >> by a customer like I might turn out to be, and I might even, I would be   
   >> tempted to rush the job, potentially making a mistake.  Or to skip   
   >> almost optional things like cleaning up great afterwards, or putting the   
   >> paper floor mat in front of the driver's seat.   
   >   
   >   
   > Well you can piss money away by changing the sensors but it's not going   
   > to clear those codes. You have a different problem.   
   >   
   > As to what the shop does, it depends on the shop. In mine if a customer   
   > brings their own parts, they are installed with no testing or warranty   
   > given because those are the parts YOU want installed. It is also noted   
   > on the paperwork that "Customer supplied parts installed per their   
   > direction" That way if the parts are wrong or don't fix the issue it's   
   > not my problem.   
   > No difference in the labor rate.   
   >   
   > Now a good shop would bring in the car, do an actual diagnostic on it,   
   > then repair the real issue, which in this case could be nothing more   
   > than a broken vacuum fitting or bad intake boot that is letting excess   
   > air in past the MAF. Or a skewed MAF that is reading a low GPS number   
   > and the PCM thinks it's getting less air than it really is. Fuel trims   
   > and O2 live data would show that and changing the sensors will do nothing.   
   > Also you may wish to know that the only sensors involved with those   
   > codes are the two upstream sensors, the downstream units are for testing   
   > the cat efficiency and as back-ups to the upstreams if they fail.   
   >   
   It always amazes me how people think that a *code reader* is the be all   
   and end all of engine diagnostics. They seem to think an understanding   
   of what's going on under the hood is no longer necessary. Unfortunately   
   the diagnostician needs a very good understanding of system operation   
   else they will be continually replacing bits which are showing   
   *symptoms* of the real fault. This current case is the perfect example   
   of a little knowledge being a dangerous thing.   
      
   --   
      
   Xeno   
      
      
   Nothing astonishes Noddy so much as common sense and plain dealing.   
          (with apologies to Ralph Waldo Emerson)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)