I have a 1998 Hyundai Accent, Its giving me a P0300,p0301,p0302,p0303, and p0304. Random multiple misfires. Ive changed the plugs and wires, and don't want to just start throwing parts at it. I was thinking maybe I should check the distributor coil next? Any suggestions or common issues with this year and model would be helpful. Thanks
That particular vehicle has a distributor-less ignition system. completely stand alone and electronic. change around the known good coils and see if the misfires on the computer change. see, what the trouble codes say is your numbers 1 thru 4 cylinders are misfiring inadvertently. if you move the coils around, which there are 4..one to 2 cylinders and if its 4 bad coils giving problems then the codes will move around. it could be the crankshaft tone wheel or the PCM as well. take it to a good diagnostic facility like a hyundai facility if you want it fixed right the first time. the hyundai parts are a little more expensive but they are the BEST part for your car, OEM parts are the way to go and the mechanic has probably seen this before and can tell you whats wrong before you leave easily.
that particular vehicle has a distributor-less ignition system. completely stand alone and electronic. change around the known good coils and see if the misfires on the computer change. see, what the trouble codes say is your numbers 1 thru 4 cylinders are misfiring inadvertently. if you move the coils around, which there are 4..one to 2 cylinders and if its 4 bad coils giving problems then the codes will move around. it could be the crankshaft tone wheel or the PCM as well. take it to a good diagnostic facility like a hyundai facility if you want it fixed right the first time. the hyundai parts are a little more expensive but they are the BEST part for your car, OEM parts are the way to go and the mechanic has probably seen this before and can tell you whats wrong before you leave easily.
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SOURCE: 2005 Hyundai Tucson 2.0L During start-up
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit
is a number other than zero, it corresponds to the cylinder number that is misfiring.
A P0302 code, for example, would tell you cylinder number two is misfiring.
Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are
mis-firing, nor why.
For example, a P0302 code means that the the car's computer has detected
that one of the engine's cylinders is not firing properly. In this case it's
cylinder
#2; same condition in P0301 - cyl #1, P0303 - cyl #3 and P0304 - cyl #4.
A code P0300 (or 301, 302, 303 or 304) may mean that one or more of the following has happened:
Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer
About your possible solutions, if there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
So, your code P0170 is one that surfaces with certain makes of automobiles more
than others. In writing this article I've added Mercedes-Benz-specific
info since it seems that M-B (and VW) are most prone to having this
P0170 surface along with misfire codes or other fuel trim codes. P0170
means there was a malfunction in the computer's control of the air:fuel
ratio.
It also indicates that the fuel trims reached their limit of adding
fuel while trying to compensate for a actual or perceived rich
condition. When the fuel trims reach their rich correction limit, the
PCM (Powertrain Control Module) sets a P0170, indicating a problem or
malfunction in the fuel trims. It may also have a P0173 referring to the same malfunction but on bank two.
Potential causes include a vacuum leak, unmetered air leaks Fuel
saturated engine oil Leak in turbo air charge hoses (if equipped)
Possibly bad O2 sensor (If Mercedes, may require adaptation with M-Benz
compatible scan tool.) Oil contamination in MAF connector or O2 sensor
connectors. Also check ignition coils, cam and crank sensors, and oil
sensor for leakage contributing to oil intrusion in wiring harness.
Defective MAF (Mass Air Flow) sensor (especially on Mercedez-Benz and
other European autos. There are a lot of problems with aftermarket MAF
sensors).
If you have this code and access to a scan tool, observe the MAF sensor
reading in grams/sec. The reading will be different for different
automobiles, so get a good spec. I'm going to stick with what would be
normal for a Mercedes (1.8L), since they have the bulk of the trouble.
Expect to see at idle 3.5-5 g/s (ideally). At 2500 RPMs with no load it
should be between 9 and 12 g/s. On road test, at WOT (wide open
throttle) it should be 90 g/s or well above. If it's not in specs,
replace it. Be careful of Ebay MAFs. Often they don't work according to
OE specifications. If the MAF checks out and there is no oil intrusion
at the connector, check fuel pressure and ensure that there are no leaks
at the regulator internally or externally. Check all vacuum hoses and
confirm none are cracked, disconnected or missing. Make sure there are
no vacuum leaks at the intake manifold gaskets or tears in the air
supply hose. If the engine is turbo charged, be sure the hoses are in
good condition and have no leaks. Leaking turbo pressure hoses could
cause a rich condition. Inspect the condition of crankcase vent hose
under intake manifold and operation of check valve in the hose. (In the
"What are the causes?" section) If there doesn't appear to be any
problems with the fuel pressure, MAF or vacuum hoses, then inspect the
O2 sensor connectors for oil intrusion. A bad O2 sensor could cause a
P0170, or P0173. Repair cause of oil leak and replace oil-fouled O2 sensor.
This is location diagram...
Bank 1 is always the side of the engine with cylinder #1.
Bank 2 is always the side of the engine with cylinder #2.
Bank 1 is the bank of cylinders on the firewall side.
Bank 2 is the bank of cylinders on the radiator side.
Sensor 1 is the O2 sensor before the cat.
Sensor 2 is the O2 sensor after the cat.
So the one you want is the sensor AFTER the cat on the FIREWALL side of the engine.
Hope this helps.
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