Random Misfire with Too rich bank 2

mandi3 · Post by **mandi3** » 22 Sep 2020, 14:20

Hello All,
Please i need help to resolve these issue on My XC90 2008 3.2.

Few months backward I filled up my tank, after a few miles away from the gas station i notice the car was jerking but not that noticable after few drive Check Engine came on with these codes:

P0300
P0304
P0306
P0306.
P0175 system too rich Bank 2

I try to clear the code but it kept popping up every time I start the Car after the engine might had cooled down. But once the code is cleared i don’t get it until next start.

2.Coupled with this, I notice high fuel consumption on the car, then i check the catalytic converters, the two catalytic converter at the Exhaust Manifold were so bad. So I changed the two, leaving the two on the exhaust pipe.

Now am getting these issues:
A. The Misfire continues, but the P0175 system too rich Bank2 had not pop up after the catalytic converter change.

(Steps taken on the Misfire issue: Spark plug and Coil from cylinder 4,5,6 had been moved to cylinder 1,2,3. while cylinder 1,2,3 plugs
and coils were moved to 4,5,6. the misfire stays on cylinder 4,5,6)

B.The Engine do not respond to a quick acceleration call on motion. But respond to slow and steady pickup.

C.The engine drive rough and with a deep sound while acceleration on high way.

Please I need help to resolving these issue. :

Post by **RickHaleParker** » 22 Sep 2020, 21:23

Things you can try.

1. Do a compression test and post the numbers.
2. On the Coil packs. Make sure the surface under the mounting bolt is clean.
(The pads around the bolt are on the Coil packs are electrical grounds.
3. Swap injectors 1,2,3 with injectors 4,5,6.
4. Clean the ECM electrical connector. The pins for 4,5,6 are A:56, A:57 & A58.
5. Check for Intake manifold leaks.
6. Check the rear Variable Intake Actuator. There are two on the front of the Intake manifold. The rear one is for 4,5,6.

mandi3 · Post by **mandi3** » 23 Sep 2020, 02:34

Thanks Rick,
I will do this above and update everyone.

chitownV · Post by **chitownV** » 28 Sep 2020, 14:22

If the engine was running well before this started to happen, then the issues came up right after visiting the gas station and filling-up, I would first suspect bad gas. I am not sure of the quality control or detergent packages with the gas & gas stations in Nigeria where you indicate you are located, but if you can run a tank of fuel system cleaner, it could be possible something got passed the fuel filter and accumulated in one or more of the fuel injectors. That is a cheap and easy first step.

A brand new catalytic can be more effective/efficient in trying to help convert the exhaust gases of even a rich condition (could be caused by poor injector spray, stuck injector(s), etc.), but it doesn't fix the engine problem.

mandi3 · Post by **mandi3** » 01 Oct 2020, 00:20

Hello ChitownV,

Thanks for the suggestion.

This had been done several times, but no effect

chitownV · Post by **chitownV** » 01 Oct 2020, 00:54

How many miles/km do you have on the vehicle? What other maintenance has been done to it?

RickHaleParker has made some good suggestions for checks and going along with the intake seems like a good area because you mention the deeper noise on acceleration, which the 3.2 can have with the variable intake system (VIS). The injectors could still be bad, even after using fuel system cleaner.

Just to check, if you remove the either the dipstick or the oil filler cap while the engine is running (parked), do you hear any air suction noise? This is checking the PCV.

mandi3 · Post by **mandi3** » 05 Oct 2020, 02:00

RickHaleParker wrote: ↑22 Sep 2020, 21:23 Things you can try.

1. Do a compression test and post the numbers.
2. On the Coil packs. Make sure the surface under the mounting bolt is clean.
(The pads around the bolt are on the Coil packs are electrical grounds.
3. Swap injectors 1,2,3 with injectors 4,5,6.
4. Clean the ECM electrical connector. The pins for 4,5,6 are A:56, A:57 & A58.
5. Check for Intake manifold leaks.
6. Check the rear Variable Intake Actuator. There are two on the front of the Intake manifold. The rear one is for 4,5,6.

Hello RickHale,

Thanks for this, I had carried out step 2 - 6. but the misfire still comes up.

Then, we noticed one of the Exhaust catalytic converted had been blocked, (Bank 2 precisely ), this was replaced.
Belt Tension Adjuster and the roller got damage (Burnt), so while replacing this things, battery and the ECM was disconnected to reset the system.

I had driving the car for few days with no check engine coming on.

I will still drive for more few days and I will update everyone here.

mandi3 · Post by **mandi3** » 05 Oct 2020, 02:06

chitownV wrote: ↑01 Oct 2020, 00:54 How many miles/km do you have on the vehicle? What other maintenance has been done to it?

RickHaleParker has made some good suggestions for checks and going along with the intake seems like a good area because you mention the deeper noise on acceleration, which the 3.2 can have with the variable intake system (VIS). The injectors could still be bad, even after using fuel system cleaner.

Just to check, if you remove the either the dipstick or the oil filler cap while the engine is running (parked), do you hear any air suction noise? This is checking the PCV.

Thanks,
For now based on the steps and changes carried out, the car had not shown any check engine error. But am Still testing.