2001 s40 1.9t p0171
#1
2001 s40 1.9t p0171
Hi Everyone,
I'm new here and am in need of help for a P0171 lean code on a 2001 Volvo S40 1.9T with 158k. The car came to me with this issue, and the previous owner said that the CEL has been on for 2 years now for that code. I replaced the breather box (it was clogged pretty bad at the drain), and I cleaned and inspected the breather hoses. I thought that would've fixed it however, no. The timing belt, and VVT gear were pretty bad and dumping oil everywhere, I replaced all that just out of the fact it needed to be done after 158k (I know, right?), along with all the seals. I did an oil change, OEM spark plugs, coils, wires, pre-cat O2 sensor (hasn't ever been done before) as well as the OE fuel filter which was pretty dirty. I reset the codes as well as disconnected the battery and put the leads together. I've smoke checked it many times for any and all vacuum leaks, did a compression check and cylinder leak down check, and no issues that I could see. I think the MAF is ok because when I disconnect it while running, the idle surges. I also vacuum checked the fuel pressure regulator with a mightyvac and it held pressure. It also does not give off a smell of fuel, so I think that it is alright. Last time I checked fuel pressure it was somewhere around 40psi, but that was before I did the fuel filter. The car runs awesome and idles very smooth, just eats gas because the ECU is trying to compensate for a lean condition. Any help is greatly appreciated. I don't think it's ever been to the dealer, I read somewhere that there was a fix for this lean condition by putting "extenders" in between the firewall connectors and O2 sensor connectors, as well as a firmware update.
I'm new here and am in need of help for a P0171 lean code on a 2001 Volvo S40 1.9T with 158k. The car came to me with this issue, and the previous owner said that the CEL has been on for 2 years now for that code. I replaced the breather box (it was clogged pretty bad at the drain), and I cleaned and inspected the breather hoses. I thought that would've fixed it however, no. The timing belt, and VVT gear were pretty bad and dumping oil everywhere, I replaced all that just out of the fact it needed to be done after 158k (I know, right?), along with all the seals. I did an oil change, OEM spark plugs, coils, wires, pre-cat O2 sensor (hasn't ever been done before) as well as the OE fuel filter which was pretty dirty. I reset the codes as well as disconnected the battery and put the leads together. I've smoke checked it many times for any and all vacuum leaks, did a compression check and cylinder leak down check, and no issues that I could see. I think the MAF is ok because when I disconnect it while running, the idle surges. I also vacuum checked the fuel pressure regulator with a mightyvac and it held pressure. It also does not give off a smell of fuel, so I think that it is alright. Last time I checked fuel pressure it was somewhere around 40psi, but that was before I did the fuel filter. The car runs awesome and idles very smooth, just eats gas because the ECU is trying to compensate for a lean condition. Any help is greatly appreciated. I don't think it's ever been to the dealer, I read somewhere that there was a fix for this lean condition by putting "extenders" in between the firewall connectors and O2 sensor connectors, as well as a firmware update.
#2
Is the engine coming up to full normal operating temperature? A bad (open) thermostat could keep the ECU in the over-rich "warm up mode".
Normally a new pre-cat O2 (aka "air/fuel") sensor will clear up a host of issues if the old one was suspect (which isn't unusual over 100,000 miles). I suppose it's always possible that your new sensor isn't working correctly.
I would clean the MAF sensor thoroughly (no easier thing to try!).
I don't remember what my 2005 V50's fuel pressure was, but 40psi doesn't sound like it could be too far off (not familiar with your particular engine, of course).
Normally a new pre-cat O2 (aka "air/fuel") sensor will clear up a host of issues if the old one was suspect (which isn't unusual over 100,000 miles). I suppose it's always possible that your new sensor isn't working correctly.
I would clean the MAF sensor thoroughly (no easier thing to try!).
I don't remember what my 2005 V50's fuel pressure was, but 40psi doesn't sound like it could be too far off (not familiar with your particular engine, of course).
#3
Hi habbyguy, thanks for the input. I did clean the MAF sensor before, but it didn't change anything. I used a Bosch oxygen sensor (never had an issue with one of them). The outside air temp reading on the dash is --- (dashed out). Would you think the ECU looks at ambient air temp and changes engine parameters based on it?
#4
Thread
Thread Starter
Forum
Replies
Last Post
850stephen
Volvo 850
28
05-25-2011 10:09 PM