Incorrect Valve Adjustment Fallout...

Incorrect Valve Adjustment Fallout...

I recently had my 90k service performed on my Honda Civic EX 2000 at a
Firestone Complete Auto Care. This included spark plug replacement,
ignition wires replacement, fuel system tune up, valve adjustment, etc.
As soon as I left with my car I noticed something was definitely wrong
with my Honda. The RPMs were sporadic and would go to just above
bottoming out at the first stop light I reached. I was concerned about
the vibrations but thought it would subside and the RPMs would return
to normal levels, but is only continued and became more frequent. After
a month I brought my car back to Firestone to explain the problems I
was experiencing and they said that the car checked out and there was
nothing they can do without an engine light coming on. The vibrations
only got worse and within a week a check engine light went on. I
brought the car back again and Firestone finally took my car to a Honda
dealership, which had to re-due the value adjustment because it was out
of spec. They also said the O2 sensor error was showing up and that is
why the check engine light came on. I have never had a problem with my
Honda before and none of these problems existed before the 90k service
was performed.

I need to know if the O2 error could be contributed to the incorrect
vale adjustment (excess vibrations) and if there is anything else I
should be looking out for because of the incorrect work.

I would greatly appreciate any help.

Ben Jones

 

wrote in

Sorry to say, but Sears and Firestone have an extremely bad reputation.
don't do that again.

They didn't use OEM, that's 100% certain.

What? What exactly what did they sell you and why? On the surface, this
sounds like a bumpf-type excuse to boost your bill.

Bad decision on two counts: 1) Leaving it for a month. 2) Bringing it to
Firestone. I would have brought it in as soon as I could have spared the
time, or less than a week.

That is correct. The MIL can illuminate with a number of O2 sensor
errors.

It is unlikely (but not impossible...) that the oxygen sensor error had
to do with the valve adjustment.

Do you know the EXACT alphanumeric numeric code that was recorded? This
is critical. Most O2 sensor failures these days have to do with the
heater circuit. If it does not say on your invoice/work order, call the
dealer and ASK. They OWE it to you if you ask.

 

I would think that a valve adjustment would be alien to shops like
Firestone. Unless you do it yourself (and you know what are you are doing),
really think you are better off with your local Honda dealer. In fact, I
recollect in my motorcycle days, tuning your bike yourself was preferable
even to dealing with your local Honda dealer.

 

I wonder why the O2 sensor needs a heater? It's already in the hot exhaust.
Perhaps to get the sensor up to operating temp quicker? (to shorten the
open loop time)

 

How long did they have the car when they did the valve adjustment?
The engine has to cool for hours before you can do the adjustment. If
they just drove it hot into the bay and did it, you know it was
botched for that reason alone.

 

The heater is intended not only to ensure fast warmup, but to make
certain the O2 sensor always remains above 750F.

The oxygen sensor needs to be at 750F to be fully operational. Even
though combustion chamber temperatures are about 2,100F, it is possible
under certain circumstances for the exhaust temperature to drop below
750F by the time it reaches the sensor. This would result in degraded
performance and increased emissions.

In addition, EPA regulations force the newest cars to use a variant of
the oxygen sensor called an "air-fuel ratio sensor". This particular
design requires to be at 1,500F before it is fully functional, and that
temperature is impossible to maintain without a heater.

 

Betcha somebody used a silicone lube or cleaner on the intake system
and it got on the end of the oxygen sensor and corrupted it. bob

 

The check engine light code was PO-131 which is 0-2 Bank 1 Senor 1...
does this help?

 

wrote in

That's P-zero, not P-oh.

The code is P0131, which according to Honda is:
Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Circuit Low
Voltage

The sensor between the exhaust manifold and the cat is returning voltage
lower than it should be sending. If the wiring or connector is not
damaged or corroded, it sounds like you need a new oxygen sensor.

You have not indicated 4-cylinder or V6. If a V6, this is the sensor
attached to the front bank.

 

Is there anyway that the O2 problem might be a result of my incorrect
valve adjustment b/c it happened soon afterwards? If not should I be
concerned with any other problems that might come after driving with
the incorrect valve adjustment for a month? My Honda is a 4-cylinder.

Thanks again for your help.

 

wrote in

Highly unlikely. BUT...

1) The correct procedure for any MIL illumination with a new code is to
turn the light off, then see if it later comes back on again with the
same code. Was that done? Many errors are transient and do not recur.
2) You may wish to check with your dealer and see if there are any TSBs
involving a P0131 code on your VIN number.

Does the car run fine now? If so, you're OK. The only real danger I can
see is the possibility of a burnt valve. If that were the case, a
compression test would identify that.

 

90,000 miles (original o2 i assume)? Yeah, it's time for an o2 to fail. I
don't run a Firestone, but I have employees who have worked there. They use
the same 3-step induction cleaning setup that nearly every major chain in
America uses (either Gumout of Run-Rite). No silicone involved.

J

 

What's a "fuel system tune up"? I hope you're not referring to an
injector flush, which is usually a waste of money and possibly a risk
(injector coil insulation can be dissolved). Many bad shops flush
injectors unnecessarily.

Doesn't 90K on a Honda mean a timing belt change is due? Sometimes
they're installed off by 1 tooth or with too much tension, and this can
cause rough running. Hondas can also be very particular about ignition
parts, so don't install magnetic supression wires (very low resistance)
in place of regular resistor wire or spark plugs that aren't NGK brand.
Hondas don't like plugs that aren't NGK, no matter what the
substitution books say. The oxygen sensor error code may be due to the
rough running.

Some Honda factory manuals can be viewed at no charge at Honda's
British web site:

www.honda.co.uk/car/owner/workshop.html

Valve adjustment is done cold, which is unusual for valve trains with
rocker arms (common for those that are adjusted with disks), and
perhaps the Firestone mechanic didn't know this. But since the car was
taken to a Honda dealer, I assume they checked the valves (ask about
this).

Use chain stores like Firestone, Sears, Pep Boys, etc., only for simple
maintenance and repairs, like oil changes, and maybe brakes and wheel
alignments. They tend to be bad for any diagnoses or service
procedures that aren't almost completely standard. I've had chains
insist that cars had no fuel or emissions systems problems because the
car's computer gave no error codes, so they'd change the fuel filter,
do a tune up, or flush the injectors without making any improvements,
but then more knowledgeable mechanics would quickly notice abnormal
readings of the computer's data stream.