kevin98208

I have a 2002 Honda Civic EX (SOHC 1.7L) with 200,000 miles on it. The MIL light went on and I received the following codes:

P0300*Random Cylinder Misfire.
P0301*Cylinder #1 Misfire.
P0302*Cylinder #2 Misfire.
P0303*Cylinder #3 Misfire.
P0304*Cylinder #4 Misfire.

The vehicle runs fine without any shuddering at idle. There are no issues with accelration. It runs the same as it did before the light came on. However, my wife did try to start the car once and it cranked over without starting. She let it set for a minute and it started up fine. It hasn't done that again.

I changed all the spark plugs with new NGK plugs. The old plugs weren't fouled. The light went off for a day, then returned. With the engine running, I removed each plug harness one at a time, and the engine idle shuddered. When I reconnected each one, the car returned to normal. So I don't have a dead cylinder.

I performed a compression test (engine warm, throttle body open) and the pressure was from left to right 195, 190, 170, 190. According to the specs in Chilton's, that is within tolerance.

I tested the fuel injectors and all showed the same resistance. I put a NOID light on the fuel wiring harnesses and each checked good.
I am out of ideas on what to do next.

ezone

Can you post the freeze frame data that was stored, along with noting which of the codes triggered the FF data record?

kevin98208

I don't have the freeze frame data. I used the scan tool from an auto parts store. However, I did just order a scan tool from amazon as I am tired of running to the store to use theirs. When I get it, I'll post the details it gives me.

ezone

Had a thought:
I've seen various engines come in with misfire codes set in several cylinders, but they were caused by a single cylinder misfiring. (Many of Hondas engines can do this if one keeps driving around ignoring a misfire problem.)

I've had to erase all the codes then run/drive it long enough to set the flashing CEL and read it with the scanner immediately while driving. Maaaybe this idea can help you?


Freeze Frame data can be a big help in diagnosing it though. The FF data can tell us the engine temperature, fuel trims, road speed, load, RPM, and more (sometimes dependent on the scanner and model year of the car) when a fault code set.


Edit: The 170 reading is a little low IMO.
Valve clearances ever checked and adjusted?

NDNV

Other ideas to check would be head gasket leak, EGR valve or ports clogged and fuel injectors.


But you are in good hands with ezone replying to your thread.

ezone

Or EGR valve stuck open. And more.

Knowing the conditions the code occurred under could help narrow down or eliminate some of the (many) possibilities. A misfire that only happens at idle would probably have a different cause than a misfire that only happens at high RPM.

kevin98208

Ok, I have the freeze frame data and code data.

7 Confirmed Trouble Codes:
• P0113: Intake Air Temperature Sensor 1 Circuit High Bank 1
• P0301: Cylinder 1 Misfire Detected
• P0302: Cylinder 2 Misfire Detected
• P0303: Cylinder 3 Misfire Detected
• P0304: Cylinder 4 Misfire Detected
• P0300: Random/Multiple Cylinder Misfire Detected
• P1456: EVAP CONTROL SYSTEM LEAKAGE ( FUEL TANK SYSTEM)

4 Pending Trouble Codes:
• P1456: EVAP CONTROL SYSTEM LEAKAGE ( FUEL TANK SYSTEM)
• P0302: Cylinder 2 Misfire Detected
• P0303: Cylinder 3 Misfire Detected
• P0300: Random/Multiple Cylinder Misfire Detected

Freeze Frame Data:

Trouble Code Triggering Freeze Frame:
P0301: Cylinder 1 Misfire Detected
Freeze Frame Data:
• PID : Description : Value
• 03 : Fuel System Status : Closed loop - using all oxygen sensor(s) as feedback
for fuel control
• 04 : Calculated Engine Load Value : 28.6 %
• 05 : Engine Coolant Temperature : 86 °C, 187 °F
• 06 : Short Term Fuel Trim Bank 1 : 6.2 %
• 07 : Long Term Fuel Trim Bank 1 : 7.0 %
• 0B : Intake Manifold Absolute Pressure : 29.0 kPa, 8.6 inHg
• 0C : Engine RPM : 1785 rpm
• 0D : Vehicle Speed : 37 km/h, 23 MPH
• 0F : Intake Air Temperature : 20 °C, 68 °F
• 11 : Absolute Throttle Position : 12.5 %

kevin98208

The repair report (used Blue Driver scan reader) states to clean the EGR valve. That seems like an easy thing to do. I'll get on that this weekend (maybe. It's snowing that skiing is calling) and see what happens.

ezone

Unplug the connector from the EGR valve and drive it around, drive it long enough to to see if the misfire issue is no longer present. Drive it under the same conditions shown in the freeze frame data if you can..


If misfire issue is no longer present with the valve unplugged, this will confirm the miss is related to the EGR system. (Unplugging the valve will set EGR codes, don't worry about it for now. We are only concerned with the misfire right now.)


It probably won't be the valve that needs cleaned, it's the EGR distribution passages in the intake--injector manifold that clog up with soot. The cylinder that misses will probably be the only passage still open.

P0113 IAT is new, check-- the sensor is in the air filter housing. Is it plugged in?
P1456, is new, is the gas cap on tight?

kevin98208

P0113--I unconnected and re-connnected all the plugs, and the code went away
P1456--I tightened the gas cap and the code went away.

I cleaned the EGR valve. It wasn't too dirty. I put it back in and drove around a while. Misfire from 2 and 3 reappeared, along with Random Misfire.

The valve cover gasket is leaking oil. I had wiped it all off and now oil is slowly drippign back down from the front of the gasket. My next step is to remove the valve cover, check all the valves and replace the gasket. Anything else I should do while I have the cover off?

Thank for all the help. With two small kids, and skiing season, I only get to work on the car a couple hours a week.

kevin98208

I did not unplug the EGR and drive around, nor did I clean the EGR ports. That is on my list to do.

ezone

I'd figure this out before taking apart the valve cover. Maybe later on you can take care of it all in one shot.

kevin98208

I unplugged the EGR valve and drove it around. I recieved only the following code:

P1491 EGR Valve Lift Insufficient Detected.


Trouble Code Triggering Freeze Frame:

P1491: EGR VALVE LIFT INSUFFICIENT DETECTED

Freeze Frame Data:

• PID : Description : Value
• 03 : Fuel System Status : Closed loop - using all oxygen sensor(s) as feedback
for fuel control
• 04 : Calculated Engine Load Value : 58.8 %
• 05 : Engine Coolant Temperature : 77 °C, 171 °F
• 06 : Short Term Fuel Trim Bank 1 : 10.9 %
• 07 : Long Term Fuel Trim Bank 1 : 1.6 %
• 0B : Intake Manifold Absolute Pressure : 60.0 kPa, 17.7 inHg
• 0C : Engine RPM : 2803 rpm
• 0D : Vehicle Speed : 95 km/h, 59 MPH
• 0F : Intake Air Temperature : 9 °C, 48 °
• 11 : Absolute Throttle Position : 22.0 %

ezone

EGR code is expected and we don't care about FF on this particular code because we already know the cause.

What we NEED to make sure of is that unplugging the EGR resolves the misfire issues. Drive around with the EGR unplugged ---- long enough, far enough, and under the same conditions that you are confident the misfire problem is no longer present.
(probably driving at a very steady speed around 20-40 mph---- your first ff data said it set p0301 at 23 mph)


That will confirm the intake and injector manifold needs pulled to clean out the egr distribution channels.

kevin98208

I unplugged it and had my wife drive around for three days (to work and back, 20 miles each way), driving kids to school and back, errands, etc. A lot of driving and it only triggered the one code.

I will reset the code, let her drive for another couple of days, and see if only that code comes back.

I appreciate all the assistance.

ezone

Right on. Just wanted to make sure you are confident the misfire is definitely not happening while the EGR is unplugged.

kevin98208

I cleared the code and had the wife drive for another day. No misfire codes, just the EGR one again.

Next step is to clear the EGR passages? Any tutuorials for that?

ezone

I don't know about a real tutorial but there have been a few threads that outline the work done. Search around, I know I've posted some pics of the EGR distribution plate in a few threads

It's a basic intake manifold remove and reinstall, plus clean all the carbon out of a bunch of passages once it's apart.

ezone

Here's a pic of the distribution plate that needs to be thoroughly cleaned of soot.... this was done during a head gasket job so the head was out of the way


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