Hi all,
Recently I have problem that I can't pinpoint to specific thing.
During normal driving, car would suddenly go to "safe mode" and it lasts for few seconds then everything goes to normal.
Codes that I get are related to Bank 2 misfire, usually P0300, P0302, P0304, P0306 and P1314. sometimes all together, other times maybe only two cylinders, then only random misfire code...
During this few seconds there is no noticeable misfire, car drives fine and pulls normal till 3000rpm due to safe mode.
Till now i have swapped coils to bank 1, put new coils to bank 2, new sparks, checked wiring, checked and cleaned grounds, new orings on intake, trims are +-5% on both banks, compression on all 6 cylinders is almost equal around 160psi. I have not done leakdown test, but there is no reason to suspect mechanical issue.
What triggers misfire codes? coils?
Could something else trigger those codes? cam sensors?

 

Swapped coils ... and have same codes?

 

Are you somehow getting any liquid into the front bank plug wells that could be shorting out plugs occasionally then evaporating off for a while?
What plugs did you fit and did you check gaps?

Have you tried swapping injectors from bank 1 to bank 2 to see if intermittent error shifts to bank 1? (Unlikely all 3 injectors are faulty, but you have ruled out so much so far).

 

Yes swapped coil and problem stays on bank 2.
Spark plugs wells are dry, no oil or any liquid, and the fault appears on rainy days same as on sunny days.
I use autolite APP103 not 100% about model. I'm using them for few years with no problem so far.
Car is converted to LPG, that means that it starts on gas injectors and after certain temp switches to LPG injectors, and fault appeared on both systems so i think that that rules out injectors.
I can se what LPG injectors are doing, and have looked at them during the issue, they are working normally.
I also checked wiring installation as LPG installation is connected inline to all injectors and crank sensor. and all looks fine, i can se live data from all sensors during the issue.

 

also, I forget to mention that I have possibility to unplug LPG installation, and I have done so and still got the same problem.

 

With swapped coils like that it's likely not the coils. It's hard to see how plugs could cause all those codes at once, too, so probably not them.

You're looking for something specific to that bank - unless looking at trims you can see both are out but bank 1 not by as much (unlikely, but easy to check).

 

Just a thought JagV8....could Luka have a Cat converter that is deteriorating and restricting flow out of that bank, which could skew HO2 sensor readings and upset fueling possibly causing potential misfires?

 

Could be, yes.

 

Cats are long gone
As I'm running on LPG, it's legal to remove cats. And car has custom headers so I think that there is no blockage in exhaust.
Both fuel trims for bank 1 & 2 are in -+ 5% range
And in that few seconds that car is in limp mode it drives perfectly fine, there is definitely no misfires. I think that I would notice misfires on three cylinders.

 

OK....a bit of a mystery to solve indeed...I will have to resort to tapping into my inner Mr Spock for some logic inspiration here.

There is a common supply to all 6 coils and what looks like a common signal ground as well........... so not likely either of those unless the earth for 2, 4 & 6 were on a separate grounding wire and lug from 1, 3 & 5. Even then you would be feeling a physical misfire.
Ignition capacitor would not be able to create noise that would reliably single out any particular coil(s).
If you are not feeling a loss of spark (dropping a cylinder or three), than that leaves one other possibility......shared coil sensor line.
On the 2002 the ECM plug EN16 has a Yellow/Green stripe wire at pin 132 which comes from the ignition coils sensor feedback on coils 2, 4 & 6.
If that common wire were damaged, high resistance(internally fractured) or shorting, then you may get intermittent feedback from those specific coils to the ECM and it would likely throw codes and go into protection mode.
If the EN16 connector or receiving pin of the ECM were corroded or tainted....same thing.
If one coil had a feedback short, it could pull down the feedback from the other two sharing the same feedback line. If you have moved those three coils to the other bank or replaced already then that is ruled out.
If not wiring or plug, then I'm guessing that you might be looking at the ECM .........but that is probably the last resort.

 

that could be it, now that I look at electrical diagram it's the only common wire to bank 2 coils.
As soon as the rain stops pouring down, I will check this wire.
thank you for your help.