Running rich (both banks) 3.2

Holcombehas6 · Post by **Holcombehas6** » 12 Feb 2022, 06:10

Good morning from Georgia everyone. I currently have 3 Volvo’s all of them have the 3.2. My wife has a 2012. We have rich codes across both banks. Not just one. As far as I can tell, I’ve replaced every sensor known to man short of the O2 sensors. They both work fine except one (bank 2) is slow to warm up, then shows fine. It will be smoke tested on Monday. Anyone have any suggestions as to what I could be missing???? It runs fine short of a random thing that happens when it is started. It feels as if it doesn’t get enough fuel, then after 3-5 seconds it’s fine. It does have some oil consumption like some of these engines do. Would that play into the rich conditions??? About a month ago, the CEL randomly went off, and my wife took it to get emissions done and it passed. Two hours later it was back on. Everyone is at a loss here. Thanks

Turbo_Boss · Post by **Turbo_Boss** » 28 Feb 2022, 11:00

Hi Holcombehas6

What are the codes you have?

What year and mileage is your 3.2

Rgds

chitownV · Post by **chitownV** » 01 Mar 2022, 19:45

Agree with Turbo_Boss' questions.

Interested to hear about the smoke test as a vacuum or intake leak could affect both banks.

Cheers

Post by **pgill** » 01 Mar 2022, 20:52

Here is what I would do in your situation.

1. Check the pressure at the fuel rail. You can measure it independently with a pressure gauge (which is a bit challenging) or swap the sensor between two of your 3.2s. I own two 3.2s and I would swap the sensor or replace it. Why? if the sensor is measuring the wrong pressure then it might convince the ECU to run the fuel pump too much which will give you a rich running condition.

2. Verify that the Voltage drop with the engine running is about 0.050 Volts between the cylinder head and Battery negative. Confirm this on your other 3.2 to make sure that you are measuring correctly. (A bad ground can cause significant problems like the one that you are suffering from)

3. Check the fuel trim what is the LTFT?

4. The Vapor recovery purge valve can fail and that would let large amounts of fuel into the intake manifold. A LR2 owner with the Volvo 3.2 recently had a purge valve failure (but the check engine light was for a evaporative emissions leak not fuel in the intake) The purge valve has a small hose connected to it, I would pinch that hose or remove it and temporarily plug it.

5. The MAF could be broken. Disconnect the MAF and run the engine without it. Does this help with the Fuel trim?

6. This last suggestion is only for the brave of heart. To confirm that the ECU can't control the mixture correctly add extra fuel to the intake air (Propane will work) if you do this the ECU should reduce the PWM (Duty Cycle) of the injectors and the Fuel Trim will be negative.

7. I lied I have one more. Remove the electrical connection to an injector and watch the misfire counts. If the purge valve is allowing fuel into the intake then the cylinder will likely continue to fire.

Note: the ECU will only allow the Fuel Trim to be adjusted by a certain amount and then it will stop adjusting.

Good luck

Paul

2010 S80 3.2
2008 LR2 3.2

Post by **pgill** » 01 Mar 2022, 21:02

One last thought

I did this recently for a LR2 owner with the 3.2

You should confirm that your 3.2 does this (if you don't have a code reader that can give you this information then you should get one)

I am going to quote myself

I did a cold start today.

0 PSI before I engaged the starter motor

On initial startup the fuel pressure spiked to 69 PSI

Then it dropped almost instantly 61 PSI

The interesting thing to note is that the RPM dropped to ~800 RPM before the fuel pressure dropped.

It took a few seconds for the pressure to drop to 55 PSI

The RPM drop seems to be attributed to the Throttle position

14.1% --> high idle

3.5% --> low idle

High Idle

here is the link

https://www.freel2.com/forum/topic37689-15.html

good luck

Paul

chitownV · Post by **chitownV** » 01 Mar 2022, 23:11

The OP hasn't responded after more than 2 weeks. Wonder what his CEL was.

Holcombehas6 · Post by **Holcombehas6** » 02 Mar 2022, 05:10

Sorry for the delayed response everyone. So smoke test, nothing. Completely clear. Mileage is 142k. Replaced MAF, PCV, fuel pressure sensor on the rail (no way to check pressure on the rail), and that’s it. Lean conditions bank one and two.

Holcombehas6 · Post by **Holcombehas6** » 02 Mar 2022, 05:12

Codes were 0172 and 0175. I also had a 0420 code for bank 2 only. I’m going to attempt to put a picture of the O2 sensors on here. They said the bank 2 rear was “slow to respond” but was running correctly once it warmed up.

Holcombehas6 · Post by **Holcombehas6** » 02 Mar 2022, 05:14

And fuel pressure seemed to be too high at startup. Like 72 psi.

Holcombehas6 · Post by **Holcombehas6** » 02 Mar 2022, 05:16

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