Code P0300 after replacing the timing chain

Hi,

The pin you removed is supposed to be removed. It is to hold the plunger from pushing on the guide until it's installed. It just makes things easier. So, if you removed it, you did the right thing.

Now, a p0300 is a random misfire. Recheck to make sure there are no disconnected engine vacuum hoses or sensors. Also, let me know if there are any other codes showing.

Here is a link you may find helpful. It explains how to locate a leak.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know what you find or if I can help in any way.

Note: I just looked again at the pic. Is it the rounded clip? That is a different thing. I'm surprised you got it off. If I recall, that prevents the plunger assembly from coming out. However, I still don't think that would cause the misfire unless it came apart and isn't keeping tension on the chain. Let me know.

Take care,

Joe

Hi,

Okay, now I better understand. My only concern with the part you removed is a bit further down the line. If excessive play is gained in the chain, it could allow that tensioner to come apart. Should it be replaced? In my mind, yes. I know you don't want to hear that, especially at this point.

Now, I don't feel that is the cause of the P0300. The idea that you have a flashing Check Engine Light when you accelerate or place the engine under a load indicates that is when you have the misfire. Do you have a live data scan tool that will show you the number of misfires by cylinder? If you do, that will help us narrow things down.

Although you purchased a great product (NGK plugs), anything is possible. Also, keep in mind that a weak fuel injector, fuel pressure, a weak coil that is arcing or has issues, compression, and so on can all be factors. I have dealt with random misfire issues that were the result of the boot that goes on the spark plug itself allowing spark within the spark plug tube because they were bad. See the pic below for what I'm referring to.

Let me know if you have a scan tool that can identify which cylinder or cylinders are misfiring. If you have such a scanner, which isn't uncommon, it will actually tell you how many misfires (per cylinder) occurred during a specific amount of time. If we can get that figured out, then we can focus on specifics.

Let me know what you find and hang in there. We'll get it figured out.

Take care,

Joe

See pic below.

Hi,

The scan tool should have a setting to show misfires per cylinder. As far as a cycle, it starts when the engine is started and stops when you turn it off. Actually, the vehicle's computer has a ceiling number that will allow it to reset, so that's why I suggest checking between starting and shutting off.

AS far as testing, I will do my best to explain. LOL

1) Disconnect the coil from the connector from the coil.

2) Next, look at pic 1 below. That is a portion of the wiring schematic to the coils. Note that each coil has a red wire, a black wire, and then one that is a different color. Red is power and should receive 12v with the key in the run position. That is our common wire.

3) Locate the red wire from the car and determine which one receives that pin at the coil.

4) We are checking the primary circuit of the coil, so set your multimeter to ohms (below see pic 2). The symbol looks like an upside-down horseshoe. LOL At that selection, we are checking how much resistance is occurring within the circuit.

5) On the ohms setting, you should have a selection based on expectations. Set it for 200 ohms. We are expecting to see approximately 1-ohm resistance, so if there is a number closer on your meter, select it. However, it needs to be above 1 ohm.

6) Place the red probe from the multimeter on the common pin. (The one that should receive power from the vehicle) and place the black terminal on one of the other two pins. I believe the common wire (red power wire) will be pin 3. Just confirm that by looking at the connector. (See pic 3 below)

7) Place the black probe from the multimeter to one of the other pins. Look at pic 4 below.
When testing, pin 3 to pin 1, you should see approximately 1-ohm resistance. Pin 3 to pin 2 should be the same. When checking between pins 2 and 3, there should be no resistance "0".

If you are right around 1 ohm between the aforementioned pins (1, 3 and 2, 3) the coil primary is good.

To check the secondary, follow this link:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Let me know if this helps or if you have other questions.

Take care,

Joe