Results 1 to 10 of 10
  1. #1
    Join Date
    Jun 2019
    Location
    BC Canada
    Posts
    5

    Default 2006 XC70 MAF code, new sensor, no change

    I'm working on a friends '06 XC70, it's got rough idle, sometimes stalls after startup, stumbles on acceleration. Seems less when it's warmed up. It started on a trip out of town, threw MAF code and fuel trim, missfire codes. A shop replaced the MAF with a Delphi one. Didn't fix anything. When she got back to town, I checked it, changed plugs (Bosch irridium) since it's due for a major tune up/service. Replaced fuel filter, No change. Threw multiple cyl missfire, MAF and cam timing codes. It'll need PVC service and timing belt (235K), but right now, I'm just trying to get it to run right.
    I've pulled the TB and cleaned, checked all charge air pipes, no leaks, checked gears and contacts in TB, look good, gears are worn, but no teeth missing. Unplug the MAF sensor and it idles and accelerates fine. I'm getting a good used OEM MAF next week, will swap out and try that first. Next I'm thinking I'll smoke it and go after the PVC system. If the MAF doesn't do it, I may change fuel press sensor, anyone have any thoughts?

  2. #2
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    521

    Default

    A cylinder misfire can sometimes be due to a faulty ignition coil. You can swap the coil of the misfiring cylinder to another cylinder and see if the misfire moves with the coil.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  3. #3
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    3,869

    Default

    If it runs fine with the MAF unplugged, then that’s likely the problem.

    Delphi isn’t a good choice.

    Used isn’t a good choice.

    A new Bosch is about $100 on Amazon.

    Start with that.
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (100K, Michelin AS3+, M1 0W40)
    2002 V70-XC (238K, Castrol Edge 0W40)
    2002 V70-T5 (195K, IPD bars, Bilsteins)
    2001 V70-T5 (76K)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  4. #4
    Join Date
    Aug 2017
    Location
    Pleasanton CA USA
    Posts
    412

    Default

    Is the fuel trim running lean? Is the idle choppy, but the engine smooth at higher RPMs? If so, it's likely getting unmetered air. Smoking the EVAP system is good, but you also want to check the 3 control valves...turbo boost valve, EVAP Purge valve, and EVAP Vent Valve. VIDA has a way to test these valves individually, which is very helpful if there is a problem with more than one valve.

  5. #5
    Join Date
    Jun 2019
    Location
    BC Canada
    Posts
    5

    Default

    Quote Originally Posted by pbierre View Post
    Is the fuel trim running lean? Is the idle choppy, but the engine smooth at higher RPMs? If so, it's likely getting unmetered air. Smoking the EVAP system is good, but you also want to check the 3 control valves...turbo boost valve, EVAP Purge valve, and EVAP Vent Valve. VIDA has a way to test these valves individually, which is very helpful if there is a problem with more than one valve.
    I'm going after the evap system next. Since it's due for a service anyway. Is there a way to check these valves without VIDA? I've got an OTC scanner.
    It's got the symptoms your explaining. It really stumbles on acceleration. But once warm idles good, fine at higher RPM's
    Looks like you can clean up the valves in the evap system, canister and just replace a couple hoses that get brittle?

  6. #6
    Join Date
    Jun 2019
    Location
    BC Canada
    Posts
    5

    Default

    Turned out that it was the PCV system. Banjo bolt was plugged. We did the timing belt, water pump, tensioner/idler at the same time. No MAF codes now, but it's throwing "Exhaust cam reset valve" 616D and 614B "Exhaust cam control" This thing threw these codes a while back and I got them to go away by cleaning the valve. I'm wondering if it's the from changing the timing belt this time though. I'll check the solenoid again, but since the code came back right after we did the belt, I wonder if we didn't reset the VVT hub when we did the belt? We just changed the belt, didn't remove or mess with the VVT hub. Does anyone know how to reset it if the timing is off a bit? I don't have a locking tool, but from what I've read, should be able to change the belt without a lock tool

  7. #7
    Join Date
    Mar 2005
    Location
    Pacific Northwest
    Posts
    1,921

    Default

    lock tool not required. I've never had to reset VVT hub on the 5+ TB job I've done (no hub or valve were ever removed). I've had to move the exhaust gear ever so slightly when putting on the new belt. Nsure why but happened multiple times. The one time using cam locker, had to remove it just to rotate gear tiny bit to get the belt on. Cam tooth marks always seems about 1/2 off. Very hard to align. top cover tilted and rides an inch above the gear mark.

    Perhaps count the number of tooth btw the 2 CAM gear marks on a known good engine pic and compare.
    Last edited by howardc64; 02-19-2020 at 12:28 PM.
    Past Volvos : 01 V70 T5, 01/02 V70XC, 02 V70 NA, 00 V70XC
    Current EV/Hybrid : 13 Tesla S85, 11 Gen3 Prius
    Friends cars under my care 17 Audi A4 Quattro DSG (B9) 05 Audi A4 Manual 6sp Quattro (B7) 04 e320 V6 Auto, 05 Accord 2.4, 08 Element 2.4, 08 Camry Hybrid
    Past Others : 01/03 VW MK4 Turbo/NA/01M. Gen1 Prius, Gen1 CRV, Gen2 Rav4, 02 Town&Country, 06 Corolla, 12 Audi A4 Quattro (B8), 07 Civic 1.6
    http://www.freewebs.com/howardsvolvos/

  8. #8
    Join Date
    Jun 2019
    Location
    BC Canada
    Posts
    5

    Default

    I didn't remove the VVT hub on this thing either. Only thing I can think of that causing the cam reset valve code is maybe the exhaust cam turned a bit when I put the new belt on. I took it apart again on Friday night and all marks were lined up. I took the belt off and made sure the cams were turned cw so the phasers were reset, put belt back on, turned over by hand, all lined up fine, code still present. Of all the timing belts I've done on different vehicles, this ones the biggest PITA. Easy to get at, sure, but the VVCT sucks @$$
    It's also got stiff spots in the steering, the column plastic cowls are binding, I'm guessing this means the notorious steering column bearing is failing, I really hate this car!
    When she gets back, I'm thinking I'll get a cam lock tool and time the belt again, other than that, the only thing I can think of is the VVT harness is broken somewhere since the valve tests good

  9. #9
    Join Date
    Jun 2019
    Location
    BC Canada
    Posts
    5

    Default

    I got a text last night and the code has went away. Re-timing the exhaust cam resolved it. The phasers can be finiky, I'm just glad I'm finally done with chasing codes on this jalopy

  10. #10
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    3,869

    Default

    If you find yourself having to re-do your work (like an improperly installed timing belt) then, yeah, they’re high maintenance.

    The cars in question are between 13 and 19 years old.

    Everything at that age has had considerable use, and quite a few miles.

    They’re gonna’ need maintenance.

    But in comparison with other new cars, this Volvo chassis is neither complex nor unreliable.
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (100K, Michelin AS3+, M1 0W40)
    2002 V70-XC (238K, Castrol Edge 0W40)
    2002 V70-T5 (195K, IPD bars, Bilsteins)
    2001 V70-T5 (76K)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •