Hello NG,

Something else in the long shot category I wanted to mention since the P2190 is so mysterious in your situation.

Earlier we discussed the PCV system and PCV related leaks. If both lines on both banks check out OK, no cracks and sealed well on the intake manifold, one other often missed source of air leak is the oil dipstick. If the oil dipstick is cracked at the head, or the O-ring seal is bad, it can cause a fault.

In this engine design, all the crankcase air generated by blowby in the W12 is accounted for at all RPMs. As in any "emissions compliant" engines today, that air must make it into the intake manifold and included with the air charge. If a leak occurs anywhere in the PCV system that amount of air is missing from the expected charge. This crankcase air generated by piston blowby and returned to the intake manifold is already past the MAF, but included in the fueling tables. So if the dipstick is not sealed, blowby will escape at the oil dipstick.

In conclusion, it would be yet another possible point of failure to eliminate by checking the dipstick for a good seal. On my car, to ensure I have a good seal I use a tie wrap to clamp down the dipstick onto the tube. This way I am assured the PCV has integrity at this point of possible failure.

 

@ all...
I swap the Coil pack from bank 2 to bank 1 and now I have a straight issue.
Bank1 running rich now So I guess my Coil Pack is bad ??
Bank 2 start to 0 fuel trim but when first start I have missfire code on Cylinder 12 and 7... that weirg..
Can it is the coil issue because the plug was New..
miss fire only happen on First Start....











I have a question so where is cylinder 7 and 12?

 

Hi NG,

Here is cylinder numbering. Lots of good information in your post. Let me examine pics and I'll reply more later. Yes, you might have arrived at the problem if coils were swapped and problem followed. If coils one or more are weak or don't fire, will cause a rich condition. Coils can fail intermittently.

One side note - you no longer need anti-seize on spark plug threads. NGK now treats the threads in production. Also concerned by what I see in the pics with condition of old spark plugs. It looks like water damage/water ingress in the spark plug wells at some point, but coils normally seal the wells. Hmmm.

 

@BWings I saw in Rockauto they has 2 version of Ignition Coil
one is NGK one Is Bosch.. the Bosch look like the OEM one...
Should I go with NGK coil because the Spark Plug is NGK also..

 

I think Bosch is OEM. Both coils should be good. It is your choice. Will make no difference if coils are Bosch and plugs are NGK. I would probably prefer Bosch, but would not reject NGK either.

 

@BWings maybe this times I will go NGK coil.. it is the first times I use NGK Coil...
because Rockauto doesn't has enough Bosch coil in stock.. only 9 left...

 

I wanted to publish this here for NG, and, in general about spark plugs. Besides item # 1, item # 4 is extremely important.

When I grew up. none of the alley mechanics I knew ever used a torque wrench. They would laugh at the notion of torquing spark plugs or most other fasteners for that matter. In those days most components were made of steel or cast iron. Today, most materials are mixed composite and alloy materials in assemblies. Mixed materials mean there are different coefficients of thermal expansion in the same assembly. Add to that, the fastener itself has its own expansion/contraction rates.

Today, I torque almost everything that uses a threaded fastener.

Now regarding item # 1 and adding the torque warning. Torque specifications usually are given for dry threads. If a thread is lubricated with anything and in this case anti-seize is a lubricant, the clamping force between mating threaded parts is increased significantly given the same torque number. The increase in clamping force is as much 20% to 25% higher at the same torque value. Torquing a spark plug which is essentially a threaded tube to 25% over its maximum clamping force can snap the tube or distort it severely, much like a torque to yield condition.

Hopefully this is a good DIY tip as many of us are changing plugs.

The following 5 things....is an excerpt taken from the NGK WS:

5 Things You Should Know About Spark Plugs

1. Anti-seize

NGK spark plugs feature what is known as trivalent plating. This silver- or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without the use of anti-seize. NGK tech support has received a number of tech calls from installers who have over-tightened spark plugs because of the use of anti-seize. Anti-seize compound can act as a lubricant altering torque values up to 20 percent, increasing the risk of spark plug thread breakage.

2. Corona stain

Corona stain is observed as a light brown or tan discoloration above the hex (located on the ceramic body of the spark plug). Corona stain is created by oil or dirt particles surrounding the spark plug. Spark plugs create a high amount of static electricity as they fire, attracting these particles to the exposed ceramic between the plug boot and the hex. Corona stain is completely normal and should not be mistaken for exhaust gas blow-by or broken seals inside the spark plug.

3. Gapping fine-wire spark plugs

In the late 1980s, when fine-wire spark plugs first appeared, installers used incorrect gap tools and procedures resulting in bent or broken-off firing electrodes. As a result, many people assumed that one cannot adjust the gap on a precious metal plug. While most NGK spark plugs are pre-gapped, there are instances where the gap requires modification. NGK recommends a wire-style or feeler gage gap tool, which can adjust the gap without prying against the center electrode. NGK also recommends adjusting the gap no more than +/- 0.008” from the preset gap.

4. Torque

Torque is critical in the plug’s ability to dissipate heat and perform properly. Always follow the manufacturer’s recommended torque specification. An under-torqued spark plug can lead to excessive vibration and improper heat dissipation, causing spark plug and/or engine damage. An over-torqued spark plug may cause thread damage or breakage, or compromise internal seals within the spark plug, leading to improper heat dissipation or exhaust gas blow-by.

5.“Copper spark plugs”

“Copper spark plugs” is a term mistakenly used for a standard material spark plug. A standard material spark plug traditionally uses a nickel-alloy outer material fused to a copper core. Almost all spark plugs use a copper core center to conduct the electricity, jump the gap, and promote heat dissipation. However, as an outer electrode material, copper would not be a good choice, as it is soft and has a low melting point (resulting in a plug that would last minutes, not miles). Nearly all NGK spark plugs, including precious metals iridium and platinum, have a copper core. When one talks in terms of nickel alloys, platinum and iridium, one is referring to its durability, or how long a spark plug will last before it needs to be replaced. However, when one talks about copper, he or she is referring to its ability to conduct electricity that is needed to fire across the gap and ignite the air-fuel mixture.

 

Mr BWings Sir ... you should wright a book on How to maintain a Bentley GT from 2004/16 ... the amount of info you provide is priceless & I know for a fact a lot of the technictions who work at Bentley follow a lot of these threads on the forum ...

 

Thank you sir. I wanted to point out the the excerpt "5 things you should know about spark plugs" is a cut/paste that came directly from the NGK site. I don't want anyone mistakenly thinking I wrote that part.

 

Just do a test drive about 50 miles at mid night
so I'm SURE my coil still fine... swap coil does'nt change anything
the fuel trim on bank 1 back to perfect now
only BANK 2 has issue when I go to the bump
SO maybe I will run a new WIRE FOR MAF and see what will happen


@BWings I torque my Plug at 30NM by Snap On electric torque wrench.. I alway torque everything in specification because I'm carefully...

 

Well NG, I have to say this - everything you are doing is a process of elimination and good that you now are sure of the integrity of each of these systems. Since you have already tried switching ECUs very early in the search for this problem at least you know one of the more expensive possibilities is not the issue.

One thing I want to restate - the old plugs show evidence of water ingress where water should never go. That makes me question where water might have done damage in other places like major harness connections. So hopefully you can look at all harnesses and connection points for evidence water might have damaged. I think you are going to the next logical place looking at the MAF wiring.

 

There's a lot in this scan. Aside from everything there is the p0234, overboost. I'll defer expert analysis to Mr.. BWings

 

Ugh....I just opened this text file.

I don't know what to say anymore. I thought you had found the problem with the coil swap.

If I were looking at this for the first time I'd say run to the MAF. It is bad. The only thing saving me from doing that is the word "intermittent" after every one of these faults. You have failures for all of the functions of the MAF on bank 2 including the IAT. Also, don't respond to every fault. Most like the misfires are secondary to the air flow issues and caused by the MAF.

Yes, NG, start with the MAF wiring.

30nm torque on spark plugs is maximum torque on a 14mm thread with crush washer and dry threads (NO ANTI_SEIZE)

 

Today I take the wiring of to inspect one by one wire
it seem ok I clean up everything.. hope it is ok..
maybe it is 5v wiring issue?
I checked all the wiring from MAF to Ecu all is 0.8 ohm
only 1 wire I cant check is 5v supply
I ll check then let you guy know

 

Hi NG,

A couple of things:

In the first pic, the replacement MAF connector does not look like the new replacement connector that was issued to fix the MAF connector problem. The replacement looks like this with blue/yellow leads.


The failure of the old type connector was fatigue in the spring pins. They would create a high resistance condition when plugged into the MAF. Here is a pic. It is of the 4 pin bank 1 side, but these are the pins that caused the MAF connector problem. You can pry off the red connector guard to see the pins. This was very hard to diagnose.


Also remember, there is one other possibility no one wants to talk about much - the front O2 sensor - bad wiring or bad sensor.