Misfires

Hello,

Was two of them wet with oil or fuel?
Also what codes are you getting ?

https://youtu.be/vMwTzURWXmk

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

Please let me know little more info.

Thanks.

Fuel no oil. Cylinders 3/4 not firing. Cylinder 1/2 fouled out black with smut.

Good morning,

The first thing I would do is a compression test to be sure the engine internals are good. You should have 140-160 pounds in each cylinder.

https://www.2carpros.com/articles/how-to-test-engine-compression

Then I would check the fuel pressure as that is a common cause for the engine misfire codes.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Are there any codes that are set?

Roy

Okay, thanks. The compression test is done already 150 per cylinder.
Fuel pressure has not been checked. Can you provide a guide for checking the fuel pressure I'm not sure where to hook the gauges. And do you know where the fuel pressure regulator is located? Thanks, JC

You will need to T into the line at the fuel rail. I attached a picture for you to view. You can rent a tester kit at a parts store for this procedure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The regulator is part of the fuel pump assembly. It must be replaced with a pump.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

There were no codes for fuel just the P2311 code for coil4. This number 4 cylinder misfire has been ongoing for a long time. But the car has always ran fine just hard on gas. Last week when I started it. It made a popping noise thru the throttle body and a sound like air leak. I replaced intake manifold and throttle body. But the motor shakes and won't accelerate at all. I have a cheap diagnostics OBD11 scanner.
Yesterday I did get a code I could not identify I think something to do with the transmission 7E9:A/T /7E8 Engine.

Replaced with pump? Not sure what that means.. can you elaborate a little more on that please?

Okay, I would remove the valve cover and inspect it under the cover. If it is backfiring, you have had a rocker arm issue. The fact that it backfires indicates that.

https://www.2carpros.com/articles/replace-valve-cover-gasket

Roy

The fuel pump contains the fuel pressure regulator. The part is not available by itself. You replace the entire fuel pump.

Roy

Oh no, you mean inside the gas tank. No way I'm not going there. I'm not a certified mechanic. I'm 70 years old I can't deal with that job. I'll have to let the dealership scan it I guess. This is a guessing game at this point and is getting more expensive by the day.

Okay, thanks.

You are welcome.

Let us know if you have any other questions.

Roy

What exactly am I looking for inside the valve cover?

Roy, what does the backfire indicate? This is my problem I've thought that all along. Do I need a valve job or what??
Thanks, JC

You are looking for anything broken. The backfiring indicates something in the valve train.

It usually shows up with a compression test.

Roy

Okay, I'll do another compression test and then pull the cover. I know where I can buy a motor for $350.00 complete.

Okay, keep me updated.

Roy

Will do. I think I'm heading in the right direction now. $250.00 later. I should have figured out the missing and the air sound not to mention the backfire.
But the compression test was good. That I don't understand. If something is collapsed. Oh well, at least it's never full around here. Thank you again I'll be in touch when I find out something. JC

You are welcome.

Roy

I see nothing unusual Roy... Help

All the valve springs are working and the lifter's are all working.

When you get it together, remove 1 plug. Start the engine with the compression gauge in the cylinder and tell me the running compression.

Roy

Okay, that won't be today but I think I found the problem. I'm sure it's the PCM the middle pin on the coil connector should be the ground right?
So connecting a test light to positive battery terminal and test light to middle pin of connector and spinning over the engine my test light should blink on off. But it doesn't. I tried it on every one of my coil connectors not just number four and it doesn't blink on any of them. I'm trying to figure out how to test the wire itself from the coil to the PCM pins but I'm not sure how that's done exactly. I have to put the cover back on before I can start it up.
I guess.

Roy, I started it up and number one cylinder is 150 and bounced around a little over 150.

My wiring diagram shows 2 wires on the coils.

Roy

Can you verify the 2 coils and the 3 wires?

Roy

That's correct the brown being the hot and the blue striped wire which is the middle pin on the coil connector when a test light is applied with power from positive side of battery with engine turning over is supposed to cause the test light to blink. But it shows no power at all. Was the running compression test okay?

Put the test light on the negative side and probe the blue stripped wire.

Roy

Ignition on or off??

Ignition on.

Roy

Thanks Roy there's nothing at all. Only the brown wire is active.

Okay, is the connector on the coil? Make sure it is then check the blue wire for power. Then start it up and see if the light flashes.

Roy

The blue wire is connected yes I tried the test on each one of the connectors.

Okay Roy, with engine running testing to blue wire and positive battery terminal light comes on steady and does not blink. That's on all cylinders. Then hooked light to ground side of battery and no light at all.

Just found something odd. Number one coil does not light up at all so the brown wire will light up but not the blue green wire.

Then the coil is bad. It is not passing current.

Roy

I tested unhooked in and hooked to the coil if the plug is not connected to the coil it shouldn't matter should it. No current is getting to the coil it s the way I'm looking at it. If I'm wrong I'll try another coil but why are none of the other connection blinking like they should be?

It must be hooked up to the coil for this test. Is the brown wire hot with battery voltage?

Roy

Yes it was . But I pulled the plug from the cylinder left it plugged to the coil and the plug was firing. I changed the coil to a coil I know to be good and installed the plug it's firing and the brown wire is hot but nothing on the blue wire.

That is because it is grounded by the ECM.

Roy