Vehicle is a 2005 X3, M54, 183,000 miles, owned and serviced by me since 58,000 miles, new Bosch O2 sensors, rebuilt VANOS unit, new Bosch coils and plugs and no codes. Vehicle has sluggish low rpm acceleration that has gradually gotten worse over the last 10,000 miles, mpg is poor. Rebuilding the VANOS made no difference. Starts good, idles smooth. I know the engine has lots of miles, but there's something not right. I have a Schwaben professional scan tool, and some of the readings I am unable to interpret. Here's a VANOS readout that concerns me and I would think displays a problem with the exhaust adaptation, but I don't know how to translate the reading to a problem that I can resolve:
http://s1232.photobucket.com/user/91...kfrkp.jpg.html
I don't see how the exhaust adaptation could possible be right, but I can't find any information on what the correct readings should be. Any VANOS experts that can advise?
Many thanks in advance.
Edit: One symptom I would like to add is that the engine has what I consider to be excessive induction sound during acceleration, almost like it's running with an unmuffled air filter, but the filter housing is tight and the main air intake into the housing is tight and sealed to the front of the radiator support.
Last edited by 91e34M5; 12-14-2017 at 09:17 PM.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
Only suggestion I have is to replace the intake and exhaust cam sensors. They can and do become less accurate without throwing codes. Night and day difference in low-midrange power.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
Have you pulled the DISA valve out of the intake? They can fail without causing a massive air leak. No check engine light the car just wont run very well.
What I find strange is that you noticed no difference after rebuilding the vanos. Changing out those old dried up o-rings which let the pistons flap about inside the unit should absolutely make a difference, giving a smoother idle and a bit more torque at low rpm. Did the job go smoothly? Did you run into any issues? Did you use teflon o-rings?
I have not yet seen a bad VANOS seal. I did rebuild the double VANOS in my old M52TU. Close to 200k miles. Was trying to solve a problem that turned out to be a bad coil. Those o-rings came out looking quite good.
My wife drives a 2004 X3 3.0 with 176k miles, no problems. I also have an 03 325i with 195k miles, original VANOS, runs great.
Vanos seals go bad by virtue of losing their ability to hold their shape after under specific pressures after becoming brittle by constant heat cycles. The factory Buna-N o-ring material has a limited shelf life in petroleum/hot conditions and eventually they're unable to keep even pressure on the outer teflon seals. This is why the replacement kits have viton o-rings which are by far superior. You usually won't feel an immediate difference in power unless the seals were terrible. It takes about 500-1000 miles for the new seals to break in.
Wow OK. I did mine and they were dry and brittle and the pistons had a lot of room to flop around. After replacing them I noticed an immediate difference, on an engine with less miles than OP. I figured most engines would be affected the same way at this mileage which is why I was suprised that OP's rebuild had no affect.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
Last edited by 91e34M5; 12-15-2017 at 05:44 PM.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
The weird noise might be the oil separator giving up.
I had sluggish acceleration and nothing seemed to improve it (although new VANOS seals made it a bit better). I tried changing out all the usual suspects as you are doing with little effect. Then I started getting t-stat problems every 6 months. This tipped me off that there must be an underlying problem. OEM t-stats don't fail that fast. Finally hooked up INPA and discovered errors in the DME. After re-flashing the DME, the car is like new again. Plenty of low-end power. Fast take-off, the works. OP, if you have a spare laptop, I would rig up INPA and see. Big bang for the bucks.
Johnny Murray
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
The entire CCV system was replaced around 15,000 miles ago with BMW cold weather parts. This was done as preventative maintenance while I had the intake removed to replace the starter. Re-sealed the intake and replaced some coolant pipes and hoses while I had it off.
Replaced the DISA valve yesterday and there was no change in performance. I reset the adaptations later on and the engine seems to be improving as it re-learns after the adaptations.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
OK, I'm good at taking things off-topic - this is the second time in this thread. (Massive apologies. I'm easily distracted/amused.) I'm also an owner of a '91 E34 M5. Out of curiosity, what are the last seven of your VIN? There's a guy in Denver on the forum whose car rolled off the assembly line immediately before mine (sequential serial numbers). Just would like to know where you are in the sequence.
Yeah I've read all about it. The thing is that the buna o-rings are just a filler. They can harden but they still support the teflon ring. Unless they were to dissolve somehow they will continue to support the teflon rings. The gap between the VANOS piston and the VANOS body is also very small. VANOS operates on a continuous supply of high pressure oil which compensates for any leakage automatically.
I am firmly of the belief that the VANOS will set a fault if its not able to hit its targets. They do fail on occasion but its not subtle. You get driveability problems and a check engine light.
A sluggish vanos almost never trips a CEL even with driveability issues unless its accompanied by a cam sensor or solenoid failure. The margin for error in timing is too great for the DME to pinpoint it.
Yeah, I've read that too. The DME monitors lobe centers down to a tenth of a degree at all times. If it can't hit its mark it will set a fault for a mechanical VANOS failure.
Yeah, the bad part is that both cam sensors have a tendency to become dull post-100k miles so the DME thinks everything is A-OK and within measurement but its really not. I've replaced the cam sensors on 3 vehicles that didn't have sensor codes and it made an unreal difference in midrange power and smoothness of shifts.
Tried to install a new exhaust cam sensor yesterday. Used a quality 5mm hex and I rounded the hex insert. I've replaced multiple cam sensors on M5x engines and N52's and never had this to happen. I was really, really tight..I guess rounding it off is better than breaking it off. What makes it so bad is that on an X3, the exhaust cam sensor is very easily accessed without removing anything.
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
Current Garage:
91 e34 M5 - spoiled & demanding 27 y/o -glanzshwarz
91 850i/6 -another spoiled & demanding 27 y/o- schwarz-gone but never forgotten
06 325i - undeserving, spoiled & demanding 27 y/o daughter's DD-hellrot
03 MINI Cooper S JCW -spoiled & demanding, yet deserving wife's DD - Chili/Panther
05 X3 3.0i -family workhorse - diamond schwarz
12 X5 3.5d - torque monster - space gray metallic
86 GMC Cabellero - Old Faithful 32 y/o DD BMW Support Vehicle
08 Cub Cadet 19HP 46" hydrostatic- yard vehicle
88 Schwinn Sierra - 1WD Off Road Vehicle
e31 & OHC BMW CCA #385540
That is another thing I don't like about servicing them. There is a possibility of damaging the teflon rings during assembly. Would suck to screw one up fixing something that isn't broken.
Take a pair of vice grips and grip the outside of the bolt and try to remove it that way. That bolt has thread locker on it and can be a pain in the ass to remove sometimes.
Sometimes with an allen type fastener you can get a second chance at it even after it seems stripped. If you tap the allen bit in with a hammer and get it fully seated in the bolt head you might have enough bite to break it loose. Those fasteners are very difficult to completely strip, more often the bit is just out of alignment and not fully seated into the head of the bolt. Just make sure the second time that you are lined up and applying torque perfectly perpendicular to the axis of rotation.
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