mk.kemkd@yahoo.com

are bad fuel give those fault code ?
P0422 and P1123

coze when I fill my tank (fuel 92) I hear knocking and pinging

and car give my those fault code

hyundai accent model 2000

hyundaitech

Bad fuel will not cause these codes. Also, using a higher octane than 87
in this vehicle will result in a lighter wallet with no benefit in most
cases.

P1123 indicates that the computer thinks the engine has a rich fuel
mixture and is leaning it out. The pinging could indicate a lean mixture.
I see from the previous thread that you've already replaced the leaking
components of the exhaust. Now, if you haven't yet verified the operation
of the oxygen sensor that was installed just before this code occurred, you
should go back to that step.

Otherwise, the potential causes of P1123 I mentioned earlier still apply:

http://talkaboutautos.com/group/alt....ges/37541.html

Also, I see that the P0422 code has returned as expected. You probably
need a catalytic converter. In fact, it's possible you should start with
the converter rather than the oxygen sensor. If it's clogged enough, it
could restrict the exhaust to the point of excessive combustion chamber
temperatures and confusing the fuel management system.

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mk.kemkd@yahoo.com

thanks for your replay but the (check lamp) was closed with it self,
after repair flex pipe and after put fuel i found this knocking and
pinging and when I asked the technic told me, here was cheated the
fuel, and this reason for this sound
and this fault code for this fuel


so I need just assure this is correct or no

hyundaitech

The best assurance is to run the car nearly to empty and refill from a
station with which you deal regularly and have had no issues.

Did you replace the flex pipe yourself, or did someone else do it? If
someone else did it, was the check engine lamp out when the car was
returned after servicing?

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mk.kemkd@yahoo.com

Did you replace the flex pipe yourself, or did someone else do it?

the technician was replaced this flex pipe.

and I was have those fault code ((P0422 - P1123))
after replaced this pipe and after many miles I was found the lamp for
check was closed

but when put the fuel I found the lamp return, and codes is ((P0422 -
P1123))

when I asked the another technician, told me the code was found in
many cars, coze have cheat fuel in my city was put mix between 80 and
90 octane


so i hope to know this code right coze this octane coze in the past
not have any knocking and pinging but have defect in the flex pipe and
replaced o2 sensor

hyundaitech

If the lamp turned out by itself and the codes were never cleared, that
would explain something I found curious.

P1123 and P0422 will normally not set together. This is because the
system cannot check the catalyst unless the oxygen sensors are functioning
normally, and P1123 would indicate a departure from normal function (not
necessarily caused by the sensor itself).

It's my hunch that replacing the flex pipe resolved the P1123 issue,
causing the lamp to go out. After some more driving, the P0422 returned
after the system was able to check the catalytic converter. Low octane
fuel *can not* cause a catalyst efficiency code. My guess is that you
need a catalytic converter, and it may be clogged to the point of
overheating the combustion chamber.

Disconnect your battery to clear the codes, and then see which codes
return. This way you'll be able to sort out whether I'm correct that the
P1123 issue has been repaired but that the code was still held in memory
after the check engine lamp went out.

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mk.kemkd@yahoo.com

I will trying, and will telling you, what done?

mk.kemkd@yahoo.com

how r u

I was read topics in the net for code ((P1123))

and this topics say test the fuel pressure and I found my pressure too
high and for resolve this

-check the return tube for fuel I found it ok
-and test the fuel pressure regulator

I don't know how I test it

in same topics one say can disconnect the fuel pressure regulator
and will the fault code was disappearing

1- I ignition of and disconnect this socket

http://img483.imageshack.us/img483/7622/dsc023106nt.jpg

2- (ignition on) found the check lamp is closed but the car not
normal, and when (ignition of) after while and return Ignition on
found the lamp return

3-
1st I was disconnect this socket and (ignition on) the lamp check
closed
2ed return socket but after many miles found lamp return

need to know if this the coze of this lamp on

and how i can test this fuel pressure regulator


or this normal when i disconnect any socket the lamp closed and return
with it self

thanks for ur cooperation

hyundaitech

What was the actual fuel pressure when you did the test? If it's too high,
you indeed need to check for blockage in the return-- this could either be
in the pressure regulator or in the return line. A quick way to test the
return line is to see if you can blow compressed air through it freely.
Also remove the fuel rail and look in it to be sure there is no blockage.
If these items are okay, then you can by process of elimination conclude
that the cause of excessive fuel pressure is the regulator itself.

1, 2, 3: The device you unplugged is the purge control solenoid. A stuck
open solenoid can indeed cause a P1123. With the solenoid connector
removed, you should not be able to blow through the valve. If you can,
replace it.

I'm surprised that unplugging the solenoid cause the lamp to go out.
Normally, this would set a code for an open circuit code for the purge
control solenoid.

Also, the ECM normally cycles this valve open and closed rapidly only at
certain times when the car is running. As an additional test for a
potential wiring or ECM problem, turn the key on but do not start the car.
Recheck to see if you can blow through the purge valve. If you can blow
through the valve with the key on (engine not running) but not with the
connector unplugged, then you should check to see if the wiring for the
valve is rubbed through on the body or engine somewhere, grounding the
signal wire. Again, I'd be surprised if this were the case, since that
should set a code for the purge valve circuit.

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