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.

 

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.

 

 

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).

 

 

 

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).

 

 

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

 

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..

 

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..

 

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

 

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

 

Thanks for the Post.
I have a 2009 Volvo S40 2.4L/i

VIN: YV1MS382692459404
WMI/VDS/VIS:
Manufacturer: Volvo Geely Sweden Volvo Geely Sweden
Brand: Volvo
Model: S40
Year: 2009
Engine: 2.4L In-Line B5244S4
Trim 718-2.4i
Engine 1617-5 Cyl 2.4 L GAS

I only just bought this car, but since there's quite a few things that can cause the P0171 code and others; it's nice to have some References on things that were tried and what resolved the problem.
Just wondering if you might have a link for the Gaskets and/or Part Number.
Oxygen Sensor Part Number?
I tend to see parts for the B5244S7 Engine... and some of the O2 Sensors say Upstream or Downstream...
So is there a Difference or are they both the same?

I know it's been a while since this has been posted; but maybe we could "Resurrect" it and Add to the Info for a More Complete Guide.
Anyone else that may be able to provide a link for a car parts website - preferably one that I can put in a VIN and Narrow the Search. eBay Fitment Charts are Very Poor- and it's a Hit or Miss in Most Cases I find.

Just a Theory to your previous Inquiry, as to why the car would run better COLD and then Poorly when Warm...
Cold makes the Parts Contract- thus Fit Tighter.
Warmer was causing them to Expand and Allowing More Air to Pass Through?

And also wondering if you have a Link for the Video that you mention - the link is not working anymore?

 

Upstream and downstream sensors are very different, and can't be mixed.

The downstream (post-catalyst) are there ONLY to monitor the performance of your catalytic converter, and don't do anything to affect how the engine actually runs.

The UPstream (pre-catalyst) sensors are there to monitor the air/fuel mixture, and can cause lots of issues like the one you're seeing (the P0171 error code, which means the engine is running lean - aka "not enough fuel / too much air".

Here's a link to the (excellent) rockauto.com website (I've pre-configured it for your engine, assuming US spec of course). You can see a lot of options for both up and downstream sensors. I tend to always choose the "brand name" sensors (Bosch, NTK, Denso for example). There are a whole lotta junk (mainly Chinese) parts out there that might cause more problems than they solve.

The reason your car runs OK when it's cold is because the care's engine management computer is programmed to run a safe, slightly rich air-fuel mixture while the catalytic converters and O2 sensors come up to full operating temperature. Once the O2 sensors show full temperature, the car starts adding fuel based on what the upstream sensor is telling the engine management computer. I consider any O2 sensor over 100.000 miles into its life to be suspect. With a P0171 code, and (assuming) around or over 100,000 miles on the car, I'd just suggest ordering a quality upstream sensor and replacing it. You may have to reset the error message via an OBD reader (something anyone who does any DIY on their car should have, or you can take it to most auto parts store for a free reading, though not all will do a reset on an existing code).

 

I have the Exact Same Car and Code.
I had an exhaust leak and Fixed that
I have an O2 Sensor I got today.... Just a Cheap one because the Mechanic thinks that is the Problem.. I hope so!
however; I am going to ask the mechanic to spray some carb Cleaner around the Intake Manifold Gasket - which is what you say was the problem for your car.

Was it the Rings or Plate that you replaced. You mentioned in your test, you had Torqued the bolts to 120 inch /pds..
There were a couple of Stripped Bolts on your car's Intake Manifold, so you torqued them all the same, for the test - is that to say, they were under torqued for the test with Carb Cleaner? - Couldn't that have given a Leak in itself?

However, was it the Round "O Ring Gaskets ---and/-or- the Flat Metal Plate that you replaced, and the Head has to come completely off?
Just trying to get the Scope of the Full Job?/ Time/ Labor- and Procedure/ Parts/

Thanks