Random Misfiring Engine S60 03

Walru5 · Post by **Walru5** » 22 Mar 2019, 20:16

Things I’m experiencing:
-Check engine light flashing
-Code P0300
-Very rough misfiring
-Engine will run idling but will stall out if I don’t rev it at 4000 for a minute before I let it idle.
-Have to jump car before starting it or it just dies after a couple cranks right before it starts.

Things I’ve tried:
-New genuine spark plugs
-New Duralast ignition coils
-Checked compression on every cylinder
-Fuel pressure is 55 at idle (Not sure this is good or bad)
-Timing belt is very tight
-Tested all the wiring for the ignition coils and all of them are good. Also tested the wiring for the fuel injectors and they all are good also.
-Cleaned out the fuel injectors and the rail with carb cleaner.

Nothing has changed after doing all of this so I’m lost now. The only other thing I can guess is a vacuum leak but I’m unsure that would cause such a rough mirfire.

Post by **RickHaleParker** » 22 Mar 2019, 22:26

Possible sources

1. Fuel stoppage.
2. Repeated cold starting where the engine coolant temperature (ECT) has not reached normal operating temperature between starts.
3. Water in spark plug wells.
4. Defective spark plugs, ignition cables, ignition coil or flywheel / pulse wheel.
5. Contaminated fuel or incorrect fuel type.
6. Blocked / leaking injector.
7. Intermittent open-circuit, intermittent short-circuit to ground, intermittent short-circuit to voltage supply, contact resistance or loose connection in the ignition system low-tension side, in the injector circuit or fuel pump (FP) circuit.
8. Blocked crankcase ventilation.
9. Damaged VVT-unit.
10. Moisture, flashover in the ignition system on HT side.
11. Leakage between cooling system and cylinder.
12. Uneven compression.
13. Restricted exhaust

Post by **oragex** » 22 Mar 2019, 22:48

How did you clean the injectors? I got a flashing light when one injector was kaput after I soaked it in acetone

Turbo, N/A? Miles ?

The fuel pressure is about good, not sure about the Duralast brand, maybe try a few used Bosch from the junkyard

Here's how to find which is cylinder misfiring www.youtube.com/watch?v=nDwtZCWU7u8

Walru5 · Post by **Walru5** » 22 Mar 2019, 23:12

oragex wrote: ↑22 Mar 2019, 22:48 How did you clean the injectors? I got a flashing light when one injector was kaput after I soaked it in acetone

Turbo, N/A? Miles ?

The fuel pressure is about good, not sure about the Duralast brand, maybe try a few used Bosch from the junkyard

Here's how to find which is cylinder misfiring www.youtube.com/watch?v=nDwtZCWU7u8

Non turbo just the 20cyl and 211,xxx miles. It was running great and this literally happened as I was driving.

I cleaned the injectors with sprays of carb cleaner, didn’t soak. I’ll check out that video and also while the car idles the lights in the car are flickering.

Walru5 · Post by **Walru5** » 22 Mar 2019, 23:19

oragex wrote: ↑22 Mar 2019, 22:48 How did you clean the injectors? I got a flashing light when one injector was kaput after I soaked it in acetone

Turbo, N/A? Miles ?

The fuel pressure is about good, not sure about the Duralast brand, maybe try a few used Bosch from the junkyard

Here's how to find which is cylinder misfiring www.youtube.com/watch?v=nDwtZCWU7u8

Checked out the video and when I unplugged cylinder 1 and cylinder 2’s ignition coils nothing happens with the car running but the other 3 change the idle.

Post by **abscate** » 23 Mar 2019, 03:04

Check that you didn’t reverse number 1 and 2 wiring harness to The coils, easy to do. I believe the colour coding is preserved across Volvo models.

Walru5 · Post by **Walru5** » 23 Mar 2019, 04:58

abscate wrote: ↑23 Mar 2019, 03:04 Check that you didn’t reverse number 1 and 2 wiring harness to The coils, easy to do. I believe the colour coding is preserved across Volvo models.

I’m not even sure I could switch them, I just looked and the wires are pretty stiff since the car is so old. The cyl 2 connector can’t reach cyl 1 because of the way it’s stiff.

Post by **oragex** » 23 Mar 2019, 07:51

Walru5 wrote: ↑22 Mar 2019, 23:19
oragex wrote: ↑22 Mar 2019, 22:48 How did you clean the injectors? I got a flashing light when one injector was kaput after I soaked it in acetone

Turbo, N/A? Miles ?

The fuel pressure is about good, not sure about the Duralast brand, maybe try a few used Bosch from the junkyard

Here's how to find which is cylinder misfiring www.youtube.com/watch?v=nDwtZCWU7u8
Checked out the video and when I unplugged cylinder 1 and cylinder 2’s ignition coils nothing happens with the car running but the other 3 change the idle.

So you have two cylinders with misfire. When you put the two coils from cyl 1,2 on the cyl 3,4, where the cyl 3,4 misfiring ? (no reaction when unplugged)

EngineeringBloke · Post by **EngineeringBloke** » 23 Mar 2019, 08:18

Did you replace the injector O-rings after the cleaning? Might be leaking fuel/air around aged rings.

Walru5 · Post by **Walru5** » 23 Mar 2019, 08:58

oragex wrote: ↑23 Mar 2019, 07:51
Walru5 wrote: ↑22 Mar 2019, 23:19
oragex wrote: ↑22 Mar 2019, 22:48 How did you clean the injectors? I got a flashing light when one injector was kaput after I soaked it in acetone

Turbo, N/A? Miles ?

The fuel pressure is about good, not sure about the Duralast brand, maybe try a few used Bosch from the junkyard

Here's how to find which is cylinder misfiring www.youtube.com/watch?v=nDwtZCWU7u8
Checked out the video and when I unplugged cylinder 1 and cylinder 2’s ignition coils nothing happens with the car running but the other 3 change the idle.

So you have two cylinders with misfire. When you put the two coils from cyl 1,2 on the cyl 3,4, where the cyl 3,4 misfiring ? (no reaction when unplugged)

When I swapped them to different slots the engine acted as when it did when I unplugged the working coils before swapping.