Help! From check engine light to fouled plugs back to check engine + plugs refouling

[larchamb]

So the new plugs they put in are fouling again. They are going to replace the ignition coil. Beyond this and original code I don't have much idea whats going on.


Any questions I should ask?

[Spartarus]

Originally Posted by larchamb

Original code was P219A
They also threw GHQ42 at me, not sure whether its related.
Will find out more on Tuesday!

P219A is air-fuel ratio imbalance. I am now thinking much less that the dealer is full of sh*t, and more that they may be on to the problem. GHQ-anything is the wrong format for an OBDII code, so I'm going to assume that's a mis-transcription and ignore it.

In your OP you told us the dealer said "something about an engine imbalance." I was initially skeptical, but seeing the code, I now see that it was a legitimate attempt to relay information, buried in a mis-transcription. However, given the nature of your post, I take it you are not well-informed. Let me fix that.

If the car is running very rich, it will do the following:
-throw that code,* and
-foul the plugs.

* In order for the code to trigger, and the plugs to foul, the engine must be running richer than commanded. (as opposed to leaner than commanded, which would have made different, albeit more exciting, issues for you)

The ECU commands a given air-fuel ratio at a given RPM and engine load; Load, defined as the mass of air entering the engine per rev. The ECU uses sensors to calculate the load, (one sensor for engine speed and a number of sensors to approximate airflow), and opens the fuel injectors by applying power to them for a calibrated amount of time (called the injector pulsewidth) to deliver a calibrated amount of fuel.

The ECU monitors how well it's doing it's job via an oxygen sensor in the exhaust, the readings from which can be used to calculate the air-fuel ratio of the burned gases coming out of the engine.

In fact, under stable conditions, your ECU uses the information from the O2 sensor to correct its fuel delivery schedule, and get closer to the target air-fuel ratio. This is called closed-loop correction.

Following me? good.

In order to throw the code, the input from the O2 sensor must be out of the acceptable range - either rich or lean. If the sensor is bad, it could throw the code when everything is otherwise just fine. BUT your plugs are fouled. That tells us three things.

1 - The engine is, in fact, running outside of the acceptable air-fuel ratio range.
2 - It is running unacceptably rich, not lean. Ergo, your plugs are fouled.
3 - The oxygen sensor is working correctly. This is im-por-tant because a faulty O2 sensor can cause a rich/lean problem by itself... But that's a closed-loop discussion for another time.

From the information I've already given you, there are 2 possible answers:

1 - Injector or other fuel delivery problem (You have 8 of them, 4 port, 4 direct, and 2 pumps. Each is what engineers like to call a single-point-of-failure for the entire system.)
2 - Air sensor problem (likely the Mass Air Flow sensor, [MAF] as that is the primary input to the ECU for air flow)

There are many ways to narrow down the problem from there. For example, your dealer said plugS were fouled... I'm assuming that means all of them. That fairly well rules out a single injector. P219A means imbalance in bank 1, but that's funny because despite having 2 banks of cylinders, this engine has only 1 oxygen sensor, and therefore, not "bank 2" code at all.. Yep, no P219B for you.

This points to a problem in all the cylinders, which points to an air metering problem.

This engine uses a hot-wire MAF, the operating concept of which I will not take the time to explain. Suffice it to say, any increase in electrical resistance in the MAF circuit (loose wire, fouled contact, chafing, damaged or broken housing, or just poor quality control) will cause the engine to think there's a whole bunch of extra air coming in.

Just theories... All of it.

[Spartarus]

Originally Posted by larchamb

So the new plugs they put in are fouling again. They are going to replace the ignition coil. Beyond this and original code I don't have much idea whats going on.


Any questions I should ask?

Read my previous post first....

NO NO NO NO NO NO NO NO NO. F*cking mechanics.

REPLACE THE COIL? Singular? There's 4 of them. 1 for each cylinder. Sounds like some missing information here. Also to answer your question YES. I would like to know which plugs are fouling. All of them or just 1? From your vague description, it's now hard to tell. And from reading my last post you should be able to tell the answer is important.

Replacing fouled plugs and coils and hoping the problem will go away is a bullshit band-aid fix that won't work for long, if it even works at all. That's just mechanics being lazy and not wanting to put in the work to diagnose the actual problem.

It's like putting a towel over a compound fracture and hoping it will go away if you don't look at it. The mechanics know that too, they're just being lazy... I know because I know many mechanics, and often have to beat them into getting off of their lazy asses and doing some real diagnosis.

If the coils were bad, the engine would throw a code to indicate the coils are bad.


The fact is, like many other people have already said, modern EFI engines DON'T FOUL PLUGS. If it's fouling plugs, there's a problem that needs to be fixed, not just replace the f*ckers and hope they don't foul again.

[larchamb]

Thanks for the info spartarus
I will be finding out more tomorrow and will ask for codes and which plugs are fouling etc.

[humfrz]

Originally Posted by larchamb

Thanks for the info spartarus
I will be finding out more tomorrow and will ask for codes and which plugs are fouling etc.

DANG, larchamb ....... either those folks you are taking your car to, don't know what they are talking about/doing or you are interpreting/relating what they say, mostly wrong.

I sure hope your car gets righted.

humfrz

[FRSBRZGT86FAN]

Originally Posted by mixtape

Shell V-Power is 93, if I am not mistaken.


Either way, I am sure your car will be fine. Pay attention to it when you get it back - just do not let that morph into paranoia.

Here in PA and NC are all the other US states it mostly is except in cali, in that area of canada it isn't.

[steve99]

Agree with what @Spartarus says.

another cause could be leaking,cracked header or leak near primary 02 sensor. The 02 sensor then sees fresh air, ie detects lean condition especially at lower rpm, the ecu then compensated by adding sh1t tones of fuel using the fuel trims and you end up actually running rearly rich (usually indicated by high positive long term fuel trims like 20% plus), but the 02 sensor still gets bursts of fresh air so ecu keeps adding fuel.

As we only have one 02 sensor for fueling all four cylinders will run rich.

seen this happen a lot with guys changing to aftermarket header but could still happen with stock header if crack leak developes and some 02 sensors have been cross threaded from factory

[larchamb]

Update:
Same code had popped: P219A
They replaced the #4 Ignition Coil and that spark plug.
Originally they replaced all 4 spark plugs.
It is an open case still, they didn't want to rack up km's testing it, so let me have it back and I will obviously take it back in if something else shows.


They updated ECM, said that downshifting kick should be solved with that.


All in all the car is running as I think it should be, much more fluid in speeds and no more drag.


If light comes on again, ill have them read this thread lol

[humfrz]

Glad your car is running better .......


humfrz

[larchamb]

check engine light back, and kick on deceleration at approx. 18 km/h
lol.....sigh

[Capt Spaulding]

I think I might start looking into the operation of your local lemon law.

[steve99]

Originally Posted by larchamb

check engine light back, and kick on deceleration at approx. 18 km/h
lol.....sigh

get the dealer to log the long term fuel trims LTFT if they are over 10% or so then something is wrong with the fueling likely stuffed or dirty sensors ( 02 or maf) or injectors or intake exhaust leaks.

[FRSBRZGT86FAN]

Originally Posted by steve99

get the dealer to log the long term fuel trims LTFT if they are over 10% or so then something is wrong with the fueling likely stuffed or dirty sensors ( 02 or maf) or injectors or intake exhaust leaks.

Originally Posted by larchamb

check engine light back, and kick on deceleration at approx. 18 km/h
lol.....sigh

Originally Posted by Spartarus

Read my previous post first....

NO NO NO NO NO NO NO NO NO. F*cking mechanics.

REPLACE THE COIL? Singular? There's 4 of them. 1 for each cylinder. Sounds like some missing information here. Also to answer your question YES. I would like to know which plugs are fouling. All of them or just 1? From your vague description, it's now hard to tell. And from reading my last post you should be able to tell the answer is important.

Replacing fouled plugs and coils and hoping the problem will go away is a bullshit band-aid fix that won't work for long, if it even works at all. That's just mechanics being lazy and not wanting to put in the work to diagnose the actual problem.

It's like putting a towel over a compound fracture and hoping it will go away if you don't look at it. The mechanics know that too, they're just being lazy... I know because I know many mechanics, and often have to beat them into getting off of their lazy asses and doing some real diagnosis.

If the coils were bad, the engine would throw a code to indicate the coils are bad.


The fact is, like many other people have already said, modern EFI engines DON'T FOUL PLUGS. If it's fouling plugs, there's a problem that needs to be fixed, not just replace the f*ckers and hope they don't foul again.

Has anyone thought of unusual valvetrain issues?

[steve99]

Originally Posted by FRSBRZGT86FAN

Has anyone thought of unusual valvetrain issues?

The cam actuator operation/position is monitored pretty well you would expect codes related to cam actuators ect if that were the case.