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 **** 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.

--
Steve W.