Engine Problems "Missfire Cylinder 2"

[nonickatall]

Hello

I have a problem, maybe someone has an idea.

In the course of rust protection on my car, I removed the battery, air filter box, cooling reservoir, mass air flow sensor and cleaned the engine compartment with the high-pressure cleaner.

However, the car has been parked for at least a week since cleaning so everything should be dryed.

I also changed the spark plugs in the course of the maintenance work.

Now I have started the engine, but it runs audibly only on 7 cylinders. I thought: Maybe I didn't plug in a sparkplug plug properly and checked that. But everything was fine. In my software I could see that the cylinder 2 shows Missfire.

After I found out that General Motors probably counts differently than is usual in Europe, cylinder 2 seems to be the cylinder on the passenger side in front.

I then swapped the spark plug wires from cylinder 2 and cylinder 4, no change.
So I swapped the ignition coils, no change.
So I unplugged the injector from cylinder 2, because I thought maybe there was water in there.
Then I thought to myself: It can't be the new spark plug that's defective, so I unscrewed the spark plug.

The top part fell off when I unscrewed it. The spark plug just broke off at the top.

That of course explains why cylinder 2 isn't running. I then screwed in one of the old spark plugs, but the engine still runs only 7 cylinders, cylinder 2 still shows missfire.

Then I thought to myself: That can't be true : Maybe it's so flooded that it takes a while. I then unscrewed the spark plug, which was also damp, and let the engine run briefly, so that the cylinder could blow itself free. I then hooked the spark plug to the spark plug connector. There is perfect spark. Then I cleaned the spark plug and let the engine run again, it still runs on 7 cylinders.

Same game, then I measured the compression, the compression is a little over 10 bar which should be ok. If the spark plug is wet, then the injector should be running and if the spark plug has spark then it should run.

I also didn't mix up the ignition cables and I'm at the end of my wits right now.

Does anyone have an idea where I can continue looking?

Excuse my English i am from Germany

 

[nonickatall]

I have also a P0200 and P0300. I think I have somewhere water in the wire harness.....

But funny that as well the sparkplug of the cylinder was broken, which still makes the missfire...

 

[rockola1971]

Lesson learned here. Dont ever use a high pressure washer on your engine or around your engine. The wiring harness plugs are made to be water resistant to moisture, not high pressure washing.

First have alook at coil harness plug for moisture, then spark plug wire for moisture and make sure it is seated on coil and plug properly. It should click when seated.

Have a look at misfire counts and what cylinder on scanner.

 

[nonickatall]

Lesson learned here. Dont ever use a high pressure washer on your engine or around your engine. The wiring harness plugs are made to be water resistant to moisture, not high pressure washing.

First have alook at coil harness plug for moisture, then spark plug wire for moisture and make sure it is seated on coil and plug properly. It should click when seated.

Have a look at misfire counts and what cylinder on scanner.

Propably not wash an american car with pressure washer.

I washed all my cars i had and countless cars from friends with a pressure washer and it never made problems. I had once a chrysler lebaron who refused work after an engine wash, but run the next day, when he was dry.

My car wash of the Escalade is 10 days back in time.

But probably it has to do with my LPG Gas System which is not original.

I drove today carefully the engine warm and hope that this warm drys out the humidity.

Hopefully tomorrow he is back in service...

 

[OR VietVet]

When you initially said pressure wash, I had an idea of the problem, like @rockola1971 has said. Breaking spark plugs means bad install habits. watch that. What is "10 bars" compression?

 

[nonickatall]

When you initially said pressure wash, I had an idea of the problem, like @rockola1971 has said. Breaking spark plugs means bad install habits. watch that. What is "10 bars" compression?

I guess this broken spark black came from the point, that one spark plug fall to the ground, when I install them. I didn't see any damage but that was probably the problem.

10,5 Bar is european unit, it's about 152 psi. I hope that is correct...

 

[OR VietVet]

IMO, I never do a compression test on one cylinder, I always do a test on the next cylinder over, #4 in you case and would do compression tests on 3 cylinders if one of the middle cylinders is the concern. Say, if #4 was the offending cylinder, I would do #2 and #6 as well. I like to compare and see if there is a drop off. But, I am detail oriented.

I would normally say "A*N*A*L" but with some of these guys, that is an open invitation to comments of the "rude/filthy" nature. But hell, I would do it too.

 

[nonickatall]

That was also my first time I did a compression test only on one cylinder.

For a compression test it does not make any sense to do it on one cylinder, but I was looking for the the cause of the misfiring on cylinder 2 and a fundamental idea is always to look for compression.

I mean this are the holy 3: compression, injection and spark...

I didn't understand the connection with a.n.a.l...

Probably that has to do with the fact, that we in Germany strictly divide, searching problems on cars and play with, whatever part, of our bodies.

 

[rockola1971]

Propably not wash an american car with pressure washer.

I washed all my cars i had and countless cars from friends with a pressure washer and it never made problems. I had once a chrysler lebaron who refused work after an engine wash, but run the next day, when he was dry.

My car wash of the Escalade is 10 days back in time.

But probably it has to do with my LPG Gas System which is not original.

I drove today carefully the engine warm and hope that this warm drys out the humidity.

Hopefully tomorrow he is back in service...

You can lead a horse to water but you cant make him drink. You go ahead and blast your engine bay with 1000psi water.

 

[nonickatall]

I found the error after a long back and forth.

The problem is that I have an LPG gas system that interferes extremely with the engine control and has additional cables and wiring harnesses and connectors everywhere.

I have now disassembled everything, checked every plug to see if there was water in it.

But it wasn't. The starting point was that a cylinder did not run and I got displayed in the software "Misfire cylinder 2".

When I checked everything again, I found that the injector plug of cylinder 7 was not plugged in.

It wasn't my turn and the high-pressure cleaner can't really loose it, because you have to pull a pin to unlock the plug. Maybe it has never sat properly and has now jumped down, due to the high-pressure cleaner?

Anyway, I plugged it in and the engine runs again, on all cylinders and also clean.

What confused me, of course, was that in addition the spark plug on cylinder 2 was broken and this message "Missfire cylinder 2".

Now I still have this message, which means, that when I look in the software under misfire and the car is idling, it shows one misfire after another.

As soon as I'm out of idle, it doesn't show any more misfire.

However, the car does not jerk when idling and drives normally.

Does anyone have an idea about this? How does it measure missfire? With the knock sensors?