Mechanics

P0300, P0301, P0302, P0303, P0304

2002 Honda Civic

Electrical problem
2002 Honda Civic 4 cyl Two Wheel Drive Automatic 106000 miles

I am getting these 4 errors. I've checked the coil pack, and wires going to the coil packs. Everything looks ok. I got 12.4V with the key on, at the connectors going to the coil packs. I got 48.5-50.2 Ohms off the coils packs.

Now I would like to check the Camshaft Sensor, and Crankshaft Sensor. Where can I probe these sensors and what volatage, or resistance should I expect to see from these sensors.

FYI, I have an ODBC program I used to scan the car's PC, and I am only getting the 4 DTC's I listed in the Subject line.

***Edit***
I found a wiring diagram. This diagram said the CKP Sensor should be: Signal Wire-Blue, Ground-Brwn/Ylw, and Power (12V)-Ylw/Blck

I found a Blue wire with a single gray (paint) dot every inch or so. I probed it. It read: 1.36Kohm key off and.26V key on.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The diagram said the TDC Sensor should be: Signal Wire-Green, Ground-Brwn/Ylw, and Power (12V)-Ylw/Blck

I found a light colored solid green wire. I probed it. It read: 3.6Kohm key off and.325V key on.


I found a darker colored green wire with a single gray (paint) dot every inch or so. I probed it. It read: 0.5ohm key off and.01V key on.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The diagram said the IAC Valve should be: Signal Wire-Black/Red, Ground-Black, and Power (12V)-Ylw/Blck

I found a black/red wire. I probed it. It read: 1.17Kohm key off and.5V key on.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Almost all of the power wires in this harness are Yellow/Black. I found one of these and probed it. It read: 12V Key On.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Also I went back to basics and took out and read all 4 spark plugs. I'm assuming #1 is the right-most cylinder when facing the engine. Plug #1 had a tan strap otherwise was mostly black. Plug #2 was 100% black. Plug #3 had a tan strap otherwise was mostly black. Plug #4 had a tan strap otherwise was mostly black. Most of the plugs were darker than I would expect, but it's all relative to the way the car has been running, I'm sure.
Avatar
Suzbandit987
March 13, 2010.




Anyone, please. Help needed.

Tiny
Suzbandit987
Mar 13, 2010.
Hi suzbandit987,

Thank you for the donation and sorry for the delay in replying.

From the symptom and condition description of the spark plugs, I believe they are bad.

The spark plugs are shorted causing the misfiring. Get them replaced and retest.

Even if the spark plugs are new, I would not discount the possibility of them going bad.

Was any repairs done prior to this occurring?

KHLow2008
Mar 14, 2010.
The 100K maintenance was complete about 3 months ago. Timing belt, Water Pump, Tensioner. I changed the spark plugs about 8 months ago, or so. At this point I was assuming the plugs looked the way they did because my wife ran the car in this misfiring condition for several miles. I will of course take your advice and we'll see what happens.

Tiny
Suzbandit987
Mar 14, 2010.
Why do you say that you believe the plugs are shorting?

*Edit*
So I assume you do not see anything wrong with the electrical measurements I took. Right?

Tiny
Suzbandit987
Mar 14, 2010.
No, the readings do look ok. When a problem occurs, we need to start with the basics to avoid unnecessary and expensive parts and time to be wasted.

If problem had started after the timing belt replacment, then you could have a timing belt synchronisation problem. Recheck the timing belt markings to ensure they are correct.

KHLow2008
Mar 14, 2010.
Ok, I changed the spark plugs. When I started the car it acted the same. Very rough idle, and acted like a car that is running a cylinder or two short. Also the car will not rev above 3K RPM. What's next? The only thing I haven't checked is the fuel injectors.

Tiny
Suzbandit987
Mar 14, 2010.
The trouble codes you posted on the title had been truncated due to space. Can you please list them all out for me so I know I jhave not missed anything.

When was the last time you retrieved the trouble codes?
Are they still the same? If yes, I would suggest getting a compression test done first.

As the spark plugs are sooty, the injectors should be working.

It definitelty seems like you have a cylinder that is not firing well.

Try to identify which cylinder is acting weird by disconnecting the injector connector one at a time to test.

Get a compression test done to see if the readings are within specs.

KHLow2008
Mar 14, 2010.
The codes are P0300, P0301, P0302, P0303, and P0304.

Tiny
Suzbandit987
Mar 14, 2010.
I ran a compression check. #1 was 235psi, #2 was 235psi, #3 was 230psi, and #4 was 235psi.

What are the odds of having good compression on all cylinders if the timing belt skipped a tooth or two?

The new spark plugs I put in this morning already look terrible, with #3 still looking the worst. Doesn't that make sense with the timing belt theory?

Tiny
Suzbandit987
Mar 14, 2010.
I went to scan for codes again, but my laptop died. I'll re-run a new scan tomorrow and post up what I find.
AD

Tiny
Suzbandit987
Mar 14, 2010.

AD