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P0171 The Worlds most annoying code

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P0171 The Worlds most annoying code

  #1  
Old 01-08-2019, 08:02 PM
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Default P0171 The Worlds most annoying code

HI all...

I got a 2006 Volvo S40 2.4i with little over 132K miles. I am not the original owner and purchased the car a few weeks ago for my work commute. However last week my check engine lite came on with the P0171 System running Lean on Bank 1. So I started to look into possible issues.. Looked at the Air Intake manifold and the seal around it, sprayed some carb cleaner around it while the car was running in idle and did not notice any improvement on idle. Also sprayed all around the throttle body with no luck. Checked and made sure that all hoses are in good condition as well as cleaned the throttle body.

This is probably worth mentioning. When the car cranks on cold startup it runs ok on idle until it worms up. After it has wormed up if I turn it off and tun it back on it runs rough on idle. It almost wants to stall at times. It also runs little below 850 rpm.. could it be a problem with the MAF sensor? How can I go about cleaning the MAF area? The freaking car computer is attached to the Air intake. also worth mentioning is that a few hours before the check engone light came on I had to jack up the car and re-position the O2 sensor that is plugged into the CAT converter. I screwed it back on and tucked the cables so they dont hang like they did. (this is a brand new O2 Sensor that I have replaced 2 weeks ago after I got the car... I may have a tiny exaust leak above the CAT converter but I am not sure.. That has been there since I got the car..

Why would the car run somewhat ok when it's completely cold until it warms up.. and when I turn it off and turn it back on is starts to idle rough...
Any help is greatly appreciated.
 
  #2  
Old 01-09-2019, 01:38 PM
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two ideas - 1) measure the resistance of the coolant temp sensor (the one under the thermostat housing) at both cold and warm temps - charts are easily found online. 2) consider that the air leak may be all the way back by the evap cannister - google "Volvo J Tube" for vids and descriptions. Next step would be to do a smoke test for the hard to find air leaks. You may also want to clean the intake with some CRC MAF cleaner (including the throttle body and MAF itself).
 
  #3  
Old 01-09-2019, 02:12 PM
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Originally Posted by mt6127 View Post
two ideas - 1) measure the resistance of the coolant temp sensor (the one under the thermostat housing) at both cold and warm temps - charts are easily found online. 2) consider that the air leak may be all the way back by the evap cannister - google "Volvo J Tube" for vids and descriptions. Next step would be to do a smoke test for the hard to find air leaks. You may also want to clean the intake with some CRC MAF cleaner (including the throttle body and MAF itself).
Thank you.. I will try that as well as changing out the MAF sensor. I will also look at the fuel pressure as well just in case. I will post results later on today.
 
  #4  
Old 01-09-2019, 08:47 PM
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Originally Posted by Zippy83 View Post
Thank you.. I will try that as well as changing out the MAF sensor. I will also look at the fuel pressure as well just in case. I will post results later on today.
Update...
replaced the MAF sensor, cleaned the MAF area with MAF cleaner, cleaned the throttle body with throttle body cleaner, put everything back together and now I have an extra code now. P0300 Random Multiple missfires.

So what is left to check is the fuel pressure, (does anyone know what it should be when the car is off and when its on?) perhaps fuel filter? I want to test everything I can before I take it to the shop and pay for a smoke test. I am really suspecting the fuel injectors but I am not sure how tontest that.

Any ides?
Thanks
 
  #5  
Old 01-10-2019, 09:20 AM
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FP should be around 55psi (double-check the manual for the exact value). Your misfires could be from contaminating the plugs with cleaner (or the gunk the cleaner liberated).
 
  #6  
Old 01-10-2019, 10:57 AM
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Originally Posted by habbyguy View Post
FP should be around 55psi (double-check the manual for the exact value). Your misfires could be from contaminating the plugs with cleaner (or the gunk the cleaner liberated).
well I am not the original owner so I dont have the manual. I will try to look online if there is any info on the FP.
 
  #7  
Old 01-13-2019, 07:28 AM
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I would suggest repairing the exhaust leak before doing any other troubleshooting. I had something similar going on and it turned out that the exhaust leak was close to the downstream o2 sensor which prevented the o2 sensor from doing its job properly. Was getting fluctuating idle and misfires.
 
  #8  
Old 01-13-2019, 09:34 AM
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Agreed - if there is exhaust gas getting out, there's probably oxygen getting in (and as pierremcalpine said, messing up the sensor's output). This assumes a leak that's upstream of the catalytic converter (a leak below that might affect the downstream O2 sensor, but that won't affect the way the engine runs at all - just the reporting of the cat's efficiency).
 
  #9  
Old 01-13-2019, 03:20 PM
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Default Why a new O2 sensor

Why did you replace the O2 sensor?
By replacing the O2 sensor you increased the accuracy of the information going to the computer. The computer had adapted to the information. You will either have to drive that way until it adapts or have the adaptations reset through VIDA.
That what I would do first.
 
  #10  
Old 01-13-2019, 05:46 PM
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Originally Posted by pierremcalpine View Post
I would suggest repairing the exhaust leak before doing any other troubleshooting. I had something similar going on and it turned out that the exhaust leak was close to the downstream o2 sensor which prevented the o2 sensor from doing its job properly. Was getting fluctuating idle and misfires.
I agree but troubleshooting the exhaust leak I have come across another possible issue. When the engine warms up and I take off the oil cap I can feel and hear some pressure being released. I have header of this problem with volvo's so two problems that need to be fixed.. Exhaust leak and pcv/oil trap issue
 
  #11  
Old 01-13-2019, 07:41 PM
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Originally Posted by Anthony Arzani View Post
Why did you replace the O2 sensor?
By replacing the O2 sensor you increased the accuracy of the information going to the computer. The computer had adapted to the information. You will either have to drive that way until it adapts or have the adaptations reset through VIDA.
That what I would do first.
I replaced the sensor because the first time (two weeks ago) the CEL came on it was calling for it. Later I found out that the vacuum pump was bad and was tripping the same fuse that controls the O2 Sensor. A week later the Lean condition appeared. Now here is where i stand. Looking to replace the pcv/oil trap and all lines that lead from it to the engine..
 
  #12  
Old 01-14-2019, 11:02 AM
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Oooh this happened to me.
Same exact codes.
Here's the bad part.
It was the Catalytic Converter...
 
  #13  
Old 01-14-2019, 11:05 AM
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Originally Posted by Corey Conklin View Post
Oooh this happened to me.
Same exact codes.
Here's the bad part.
It was the Catalytic Converter...
Already changed... It was bad and making noise when I got it. Changed it, and shortly after that the O2 sensor..
 
  #14  
Old 01-27-2019, 03:16 PM
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Originally Posted by Zippy83 View Post
Already changed... It was bad and making noise when I got it. Changed it, and shortly after that the O2 sensor..
Last week I got around and changed the PCV Oil Trap and the hoses that came with it. I also dropped the oil pan and cleaned it as well. Sadly it did not do anything. Car behaves the same way a it did before. ON cold startup it seems to be fine in idle... Once the engine warms up and I turn it off and back on it starts to idle rough for about 30 sec. After 30 sec the RPM go up a bit but still runs little rough. However the Random Multiple misfires are gone from the OBD2.

I found out that this engine type doe not have a fuel filter, the last thing I could do is check the fuel pressure..
 
  #15  
Old 02-02-2019, 08:29 PM
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Originally Posted by Zippy83 View Post
Last week I got around and changed the PCV Oil Trap and the hoses that came with it. I also dropped the oil pan and cleaned it as well. Sadly it did not do anything. Car behaves the same way a it did before. ON cold startup it seems to be fine in idle... Once the engine warms up and I turn it off and back on it starts to idle rough for about 30 sec. After 30 sec the RPM go up a bit but still runs little rough. However the Random Multiple misfires are gone from the OBD2.

I found out that this engine type doe not have a fuel filter, the last thing I could do is check the fuel pressure..
So I took some carb cleaner again and went to town. From different angles spraying around the intake manifold I noticed that the engine wants to stall during the heavy spray. Please see video below.

https://www.youtube.com/watch?v=ZJ-i...ature=youtu.be

So my question would be shouldn't the RPM go up when I spray the carb cleaner if there is a vacuum leak?

Once I took off the intake manifold I was able to identify which gaskets are bad..




You can see where the carb cleaner got in behind the gasket. Locally I cant get these gaskets anywhere so I took the one that didn't leak and replaced it, but got the same result. I did torque the bolts to 120 inch-pounds. There are a couple of bolts that slip so I torqued them all the same for the test. Will have to re-thread a couple...

Any clues?
Thanls
 
  #16  
Old 02-05-2019, 08:31 AM
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Originally Posted by Zippy83 View Post
So I took some carb cleaner again and went to town. From different angles spraying around the intake manifold I noticed that the engine wants to stall during the heavy spray. Please see video below.

https://www.youtube.com/watch?v=ZJ-i...ature=youtu.be

So my question would be shouldn't the RPM go up when I spray the carb cleaner if there is a vacuum leak?

Once I took off the intake manifold I was able to identify which gaskets are bad..




You can see where the carb cleaner got in behind the gasket. Locally I cant get these gaskets anywhere so I took the one that didn't leak and replaced it, but got the same result. I did torque the bolts to 120 inch-pounds. There are a couple of bolts that slip so I torqued them all the same for the test. Will have to re-thread a couple...

Any clues?
Thanls
Issue resolved... Found out that there was a bad gasket on the Lower intake manifold facing the cylinder head.
 
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