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thebesthonda
thebesthonda, ASE MasterTechnician
Category: Acura
Satisfied Customers: 3084
Experience:  26 years experience
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2001 acura TL: misfire..p300..Ive replaced the coils and plugs

Customer Question

I have a 2001 acura TL with a misfire and cod p01399 and p0300-p0306. I've replaced the coils and plugs with no change.
Submitted: 4 years ago.
Category: Acura
Expert:  Jim replied 4 years ago.

The following would need to be checked for this problem.

 

Verify that the correct factory spark plugs are installed in the vehicle.

Check the spark output of each ignition coil. If there is a weak coil, it can cause the Engine Control Module (ECM) to indicate multiple misfires. Pull one coil at a time to determine what cylinder may have the misfire.

Unplug the Exhaust Gas Recirculation (EGR) valve and verify that it is closed and that the EGR system is not causing the misfire.

Add fuel to the engine through the throttle body and see if the misfire goes away. If the misfire does not go away and spark is good then check for tight valves. If the misfire does go away, then check fuel quality and injectors

Customer: replied 4 years ago.
I already replaced plugs and coils and confirmed the EGR is closed. I was thinking fuel injection is there any easy way to confirm an injector issue? Is this a common problem on this model? I am an ASE L1 tech so I just need manufacture specific help
Expert:  Jim replied 4 years ago.
Add fuel to the engine through the throttle body and see if the misfire goes away. If the misfire does not go away and spark is good then check for tight valves. If the misfire does go away, then check fuel quality and injectors
Customer: replied 4 years ago.

Sorry Jim I was looking for more common problems on this modle if you are not an acrua tech please don't waist my time or yours.

Expert:  Jim replied 4 years ago.
These are the most common problems on this vehicle for this combination of codes you supplied, and I have not had any problems finding and fixing Acura's with these same codes following these exact procedures, which have been given to you. I will open your question up to the other technicians.
Jim, ASE Certified Technician
Category: Acura
Satisfied Customers: 1100
Experience: ASE Certified A6,A8,L1 and California Licensed Smog Technician
Jim and 2 other Acura Specialists are ready to help you
Expert:  thebesthonda replied 4 years ago.
Hello. Do you have a scanner that will read map sensor voltage at warm idle? If so, let me know the reading.
Customer: replied 4 years ago.

No onl;y can pull codes

Expert:  thebesthonda replied 4 years ago.
Ok, how many miles are on the car?
Customer: replied 4 years ago.
103,000 just bought from a used car lot.
Expert:  thebesthonda replied 4 years ago.

The most common cause for this is a clogged egr port. I see this all the time. The intake manifold needs to be removed to clean out the tube that runs from the bottom of the egr through the intake manifold. Over time, it gets clogged with carbon deposits and restricts the air flow...causing misfire codes. Normally these will clog between 100-150k miles.

 

The reason I asked about a scanner is to check for tight valves as Jim mentioned..this is very common after 80k. The map sensor should read around .95 volts when warm, idle. If it reads lower than .90, the valves are too tight. Checking it with a scanner avoids the fees of manually tearing into the valves to check them.

Customer: replied 4 years ago.
I considered an EGR problem but the misfire is at idle too and I tried blocking off the EGR ports with no change. I may try back probing the map sensor with my DVOM and checking the voltage. What is the fix for tight valves?
Expert:  thebesthonda replied 4 years ago.

If you will pull the top plenum off and turn it upside down, the port will most likely be clogged...it would take about 30 minutes to check it. Even if it's not, its a good idea to clean it out....its sure to be getting dirty with 103k.

 

The valves on these are adjustable just like all other Honda's so they will adjust out if necessary.

 

You may also want to check the fuel pressure. I have seen a few regulator problems with these.

 

Fuel Pressure regulator

Pressure with regulator vacuum hose disconnected

'99-'00 models: through engine number(NNN) NNN-NNNN/p>

280-330 kPa (2.9-3.4 kgf/cm2, 41-48 psi)

'00 model (engine number(NNN) NNN-NNNNand later), and '01-'03 models:

330-380 kPa (3.4-3.9 kgf/cm2, 48-55 psi)

 

You might also want to check the compression on the problem cylinders just to be sure. It needs to be around 120-130 psi

thebesthonda, ASE MasterTechnician
Category: Acura
Satisfied Customers: 3084
Experience: 26 years experience
thebesthonda and 2 other Acura Specialists are ready to help you
Customer: replied 4 years ago.

Ok thats the kind of info I was looking for Thank you

Expert:  thebesthonda replied 4 years ago.
My pleasure.

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