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rough idle especially in reverse with wheel turned to the right

Help, Advice, Owners' Discussion and DIY Tutorials on the Volvo S80 model. Sometimes called an "executive car", the S80 was and continues to be Volvo's top-of-the-line passenger car.
hu5ker555
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Year and Model: 2008 S60, 2005 S80
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hu5ker555

rough idle especially in reverse with wheel turned to the right

Post by hu5ker555 » Sat Nov 09, 2019 3:47 pm

2005 S80 2.5T

My S80 has a rough idle and will sometimes stall out, especially if it's in reverse and the wheel is turned all the way to the right. I've pulled codes and there is a P0101 and P2188...probably a small vacuum leak somewhere but haven't been able to pinpoint it. Not sure why the reverse and wheel turning would make things worse, and even stall the vehicle. Any suggestions appreciated.



jimmy57
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Re: rough idle especially in reverse with wheel turned to the right

Post by jimmy57 » Sat Nov 09, 2019 4:15 pm

Check motor mounts and the orque mount and look at the hose that comes from MAF sensor to turbo inlet. The motor moves a different way fore-aft for reverse and the engine moves left -right due to steering rack being on the subframe and subframe mounting the car body with rubber bushed mounts. You may be opening a crack in the MAF to turbo hose and the MAF signal goes low and fuel quantity is cut. If you unplug the MAF and then start engine and the probllem is gone that confirms it but will set a fault code. WHen the MAF is unplugged the ECM runs a default program not needing the MAF input.
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hu5ker555



hu5ker555
Posts: 96
Joined: Wed Nov 30, 2011 6:33 am
Year and Model: 2008 S60, 2005 S80
Location: Kansas
Has thanked: 16 times
Been thanked: 1 time
United States of America
hu5ker555

Re: rough idle especially in reverse with wheel turned to the right

Post by hu5ker555 » Mon Nov 11, 2019 8:22 am

Thanks for the good ideas there. I'll look more closely at the MAF to turbo hose, especially with the car in reverse and wheel turned fully. Maybe I'll detect some hissing sound or could spray some carb cleaner around there and see if it changes the idle.

If that doesn't help, I think my next step might be to smoke test with a cigar. Was thinking I would put a rubber glove on the intake hose just downstream from the MAF, stick a rubber hose in one of the fingers, and puff cigar smoke down the hose.

Also...just curious...you mentioned that if I unplug the MAF the problem might be gone but it will set a fault code. If this happens, is there harm in driving the car with the MAF always unplugged?



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