Check engine light on and code P2191

Good afternoon,

This code usually indicates that the system is running lean.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

If you have a scan tool, can you tell me the long-term trim percentage? This will tell me if you have a vacuum leak.

Roy

Engine Control
P2191 System too Lean at Higher Load (Multiple) (Bank 1) - General Information

General Description

In order to provide the best possible combination of drivability, fuel economy and emission control, the PCM uses a closed loop air/fuel metering system. The PCM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The PCM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The PCM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the amount reaches excessive levels because of a lean or rich condition.

DTC Description

If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The PCM sets DTC P2191 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its maximum threshold at part load.

Engine Control
P2191 System too Lean at Higher Load (Multiple) (Bank 1) - Inspection/Repair:_:W/Harness Inspection

Check intake/exhaust system for leakage

1. Visually/physically inspect the air leakage in intake/exhaust system for the following areas:
- Vacuum hoses for splits, kinks and improper connections.
- Throttle body gasket.
- Gasket between intake manifold and cylinder head.
- Seals between intake manifold and fuel injectors.
- Exhaust system between HO2S and Three way catalyst for air leakage.
2. Was a problem found in any of the above areas?


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3. Inspect the leakage in EVAP. system for the following conditions:
(1)Remove the manifold side vacuum hose from the EVAP canister purge valve.
(2)Using a hand vacuum pump apply specified vacuum(Approx. 15 in, Hg) to the manifold side of the valve.
(3)Does the valve hold vacuum?


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Sensor Inspection

NOTE:
Refer to "Signal Waveform & Data" in the "General Information" procedure.

1. Visually/physically inspect the front HO2S for the following conditions:
- Ensure that the HO2S is securely installed.
- Silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false(high) voltage signal.
- Fuel, engine coolant or oil contamination.
- Use of improper sealant.
- If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "Verification of Vehicle Repair" procedure.
2. Visually/physically inspect the MAFS for the following conditions:
- Contamination or deterioration.
- Poor connection or damaged harness.
3. Check for an intermittent TPS1 false signal. TPS1 signal displayed on a GDS should increase steadily when depressing accelerator pedal after starting.
4. Verify that the PCM ground connections are clean and properly tightened.
5. If test result is NG, repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
If OK, go to next step as below.

NOTE:
If the contamination is evident on the HO2S or MAFS. Fix the source of the sensor contamination before replacing the sensor to prevent future contamination.

Positive Crankcase Ventilation System Inspection

1. Check the engine oil level. The oil level should be between the min. and max. marking. Fill to the correct oil level.
2. Check crankcase ventilation valve for improper installation, damaged o-rings and malfunctioning.
3. Warm up the engine to normal operating temperature.
4. Connect GDS and note the "SHORT TERM FUEL-B1" parameter on the GDS data list.
5. Disconnect and plug the positive crankcase ventilation at the intake manifold side.
6. Monitor the "SHORT TERM FUEL-B1" parameter on the GDS data list once again.

Specification :The value should remain more or less unchanged

7. Is the displayed value within the specified value?


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Fuel System Inspection

1. Fuel Line Pressure Inspection
(1)Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
(2)Install a fuel pressure gage.
(3)Inspect fuel pressure with normal idle status.

Specification :338 - 348kPa(3.45 - 3.55kg/cm2)

(4)Is fuel pressure within the specified value?


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2. Fuel Pressure Hold Inspection
(1)Stop the engine and check for a change in the fuel pressure gauge reading.

Specification :After engine stops, the gauge reading should hold for minimum 5 minutes

(2)Is fuel pressure within the specified value?

Thanks for the quick response. Unfortunately, my scan tool only provides short term trim values. I think it's time I invest in a better scan tool. It does show some live data but no long term trim.

You know after reading your notes something does come to mind that could be causing this code. Recently, Kia replaced the engine due to recall. When I got the car back I revised all fluids and belt etc... I noticed that the oil level was high and I questioned them about it. They looked at me like I was crazy, checked it, and told me that's how its supposed to be. Well I've never gotten an oil change from them and gotten an above max reading on dipstick before. This might be the reason for the code. Do you think it's possible that my PCV is getting oil in it and causing this vacuum issue? But that would cause less air and a rich code wouldn't it cause oil would clog or restrict air passage. Your notes above mention checking that and got me thinking. What do you think?

No to the high oil level.

The reason I asked for the long term is to see if it is running lean. That would lead me to believe there is a fuel delivery issue.

Roy

I will buy a better scan tool check long term trim values and let you know what i get.

Okay, keep us updated.

Roy

Yes thank you for your prompt attention.

We are always glad to help.

Roy

So I purchased a better scan tool and I ran a check on long term fuel trim and it fluctuates between 26 and 28 at idle. Is that at or around normal?

No, not at all. It should close to 0 and maybe about -3 to about +4.

You have a vacuum leak somewhere causing this. Get some carburetor cleaner spray and with the scan tool hooked up and the engine running, spray it were the intake manifold meets the head. If the readings change, the intake manifold gasket is leaking.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

https://www.2carpros.com/articles/replace-intake-manifold-gasket

Roy

In November Kia replaced the motor due to engine seize and was under a factory recall. (Thank you Kia) however when they returned the car to me it had this code. (P2191) I returned it the next day and they replaced the intake manifold gasket thinking that was the cause for code. I'll take your advice and do carburetor cleaner procedure. See what happens. Will my turbo be okay with carburetor cleaner spray?

Yes, it will.

Roy

Okay, thank you for the assistance.

You are welcome.

Always glad to help.

Roy

Is it a possibility that my evap system could be causing this lean code?

No, it would cause a rich code if fuel vapors leaked into the intake system.

Roy

Okay, thanks.

Okay, so smoke test done on evap system and no leak detected. All air intake checked for leaks and none found. Fuel pump is putting out good pressure but quickly drops after turning engine off. Going to replace fuel pressure regulator in the fuel pump assembly and see if this is good fix for P2191. Thoughts?

I would replace the entire pump assembly, not just the regulator. The regulator is part of the pump assembly. If you have it out, I would just replace it.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

With the pressure bleeding back as it is, there is a good chance it is the check valve in the pump itself, not the regulator.

Roy

Okay, and I have a new pump in the box. There are only two differences in the part in box as compared to existing assembly. The sending unit looks a little different but I am sure the functionality will be good on it. Then on top there are two electrical connectors which they both have. There is a three prong connector and a four prong pyramid shaped connector. The difference is in the pyramid connector. My existing pump assembly pyramid connector has four prongs in it and new pump assembly pyramid connector has five prongs on it. Do you think that will make it not function properly? My parts source has been very consistent in the past 10 plus years in providing parts that fit and work good. What are your thoughts please? Thank you in advance.

I guess the real question is, could this loss of pressure be causing the P2191 code in your experience?

No, it does not sound right.

Do you have the part number from the old pump?

If there are 5 prongs, then you need the correct connector. I attached possibiles for you below and the OEM number is there as well. It has to be the exact part number.

Roy

I do use RockAuto.com for my parts source. The pump I purchased is a TYC model no.150368. Which is what RockAuto lists for my particular year, make and model.For a 2.0l turbo engine. When I visit the www.tycusa website they show same pump as fitment for my particular vehicle.

Can you post a picture of the new pump and the old pump side by side?

Roy

So I just finished installing new pump and drove it for 15 miles. I don't notice a difference and to be quite honest I have tried so many things. I have lost all hope in that getting that code removed. Six months of research,hundreds of dollars on dealership, mechanic and my adding parts in hopes that the new parts will remove this stubborn P219. And it keeps coming back. And the dealership suggests that the remedy is buying a new one. Lol!! They wanted to throw a new pump on there for $680.00 but could not guarantee that would remove the code. Now my registration will expire on 5/31/21 and I use my car to work. Work will not allow me to use my vehicle with expired tags. I'm bumming. I loaded some pictures anyway.

Okay, it looks like the fuel pump is correct as in the diagram I attached, the connector only uses 4 wires in the connector. The fifth cavity is empty.

You need a scan tool to measure the long-term trim percentage. That will tell me how lean this is running. It is also possible the injectors are partially clogged. Additives have no effect on cleaning. The only way to clean them is to disable the pump, use a system that connects to the pressure port, and injects cleaner directly into the system. The engine will run on this fluid and does a great job cleaning the injectors.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

I also attached the flow chart for the code to follow. The only catch is you need a scan tool for the testing. A code reader will not help at all.

Roy

So I put in new pump assembly and ran it for almost 3 hours straight last night. After that time and 91 miles check engine light came back on just as I was getting my hopes up. That was the longest time elapsed and mileage covered after clearing the code and it coming back on. Same code P2191. still idles a little rough. Still not getting optimal gas mileage but not off by much. No other performance issues other than that. Hooked up scanner and long term fuel trims fluctuate from 15 to 18 at idle. This is an improvement from the last time I checked them when they were at 25 to 28 at idle. I put pictures for you to see below. What do you think? I really appreciate your attention and help on this as I am really struggling to correct this issue.

I think you need to have the injectors cleaned. They sound like they are not delivering enough fuel.

Roy

Can you recommend a business that does that well and affordable? Or do you know of a system that I can use that is easy to use, effective and affordable?

BWD or Borg Warner makes the tool for the cleaning. You can check with the parts stores for availability in your area. The cleaner is extra but only a few dollars.

Roy