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Maintenance Time | Camshaft Position Sensors & While You're In There Stuff...

4K views 47 replies 13 participants last post by  umichchris 
#1 · (Edited)
Not too long ago I noticed I was down on power and experiencing an intermittent CEL. Pulled the codes and found out it was time to replace my camshaft position sensors. I'm doing all four. But this was a good opportunity to address a couple other items while I was in there. My passenger side VCG wasn't in the best condition so I will do that too. Also, this is a great time to treat the old girl to fresh coilpacks and spart plugs. After pulling them, I noticed they are the originals with a production date of Nov 27, 1999! I'm also doing an oil change, new air filters and transmission fluid.


The next big maintenance project will be the rear end. The differential has a small leak and I'll address a few other items 'while I'm in there' as well.


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#5 ·
Did this same job last summer. None of it is difficult, just takes time. The cam position sensors made a huge difference for me.

great looking car and garage.
 
#13 ·
Ok ok let me start by saying ____ this job as a DIY. It truly sucks lol

thank you for the suggestion to remove the heater hoses going into the firewall for a bit more clearance…that helped a lot. However, the amount of space available is just damn near impossible. I highly recommend you find a good indy for this one lol

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#8 ·
If you pull the cap and look at the thumb locks for turning you will see one has a small hole in it, that is a bleeder to allow pressure out. Even if everything is perfect some mist will come out it. Yours could be normal if never wiped off. Clean it all and see how fast it comes back. Practically every BMW, with this bottle, I have seen has some wetness.
There is something common to M5s that amplifies this weeping. The hose are poor and sweat after a few years of service. When they start sweating or leaking air gets sucked in when running and return more pressure to the bottle which makes more oil come out the bleeder hole. If you pull the belly pan and look up around the lines you will see oil coating the hoses which means it might be time to replace. Another indicator is turn the wheel to either lock and if the pump starts squealing that means air is in the system which will likely be coming from the lines being past do for replacement.
This is the Coles notes version, there are plenty of threads you could read on the topic. Some have installed a catch can for the bleeder hole. If lines need to be replaced there are better options than stock as stock will likely start sweating again soon after replacement.
 
#9 ·
IMO, wipe it clean, remove the cap and you will barely be able to notice the large O ring that's essentially mashed down so hard it almost looks like it is part of the threads near the top of the cap. Order a new one and replace. This is 99% of the reason PS reservoirs leak fluid and most people assume it's coming out of the weep hole. But in general if that does not clean up the fluid near the lines, it's likely you should replace both of those lines AND the reservoir due to the mesh screen inside that's sealed in there. Not a bad job if you have a lift like you do, I just did this. There are small O rings on the other side where they go into the aluminum holder block, order new O rings for the additional line there as that one does not need replacement usually as often as the other 2 lines coming from the reservoir. Much of this fluid will manifest itself down on the connection to the power steering pump. So If you want to replace all of it, forget about just doing the O ring. But if you want to clean and check and see if that's it, it's an extremely cheap fix.


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#10 ·
Very helpful!

I will start by cleaning everything up and trying to find where it's coming from. I normally pride myself on how immaculate i keep my engine bays so peeling back a few components and seeing this gunk...I knew i needed to address it properly.

I will more than likely just order all new parts and replace them all when its time for me to do the rear end maintenance work.
 
#15 ·
Hmmm i didnt think of that because the sensors are at the top of the engine at the back…figured the reach would be even worse from below.

Well, all four sensors are out now…doing the valve cover gaskets now then getting it all buttoned back up..
 
#21 ·
I don't know guys.. I read a couple posts on it, got the right tools and it really wasn't that bad from the top. It's probably easier from the bottom having stared at them quite a bit on my header install. A head lamp and a hex driver helped me the most.
 
#22 ·
Just had an intake CPS replaced on my 02 M5 With 199,000 miles. Was throwing a P0340 code. Date stamped on the old CPS 10/2001. Stealer wanted $475. My great mechanic in Allston, MA $257.
Not sure I understand the question. Do you have a hoist?
I guess it depends if you took the bracket off as part of the valve cover job. If you did then the answer is the same, remove the bracket on the hoist.
Admittedly I was hyper focused on getting the valve cover gasket job done and other vacuum items replaced under the plenum, so checking my CPS was an afterthought, but in hindsight I should have at least checked to see if they were the old versions. So I am unfamiliar with this bracket you are all referring to, but I do know that I could see the CPS inserted into the valve train near the cam sprocket from some pictures I took. Seemed like it was RIGHT THERE for me to do. Maybe that's not the case, but having the valve covers off seemed like it would free up a ton of room to get into that tight spot.

I have a Harbor Freight engine brace that rests on the interior fender seams and can hold and lift the engine a little, do you think something like this would make this easier?

Edit: I also have a 2 post lift.
 
#23 ·
I did mine when the valve covers were off. You're right that you can see them right there (and they mock you). On the back side of the head, there is a black metal bracket that has two bolts in it. The bracket is a metal mount that goes up into the wire harness box (long thin black plastic box). That bracket blocks access to the CPS bolts and has to be removed. Once that's out of the way, the CPS sensors are a breeze. It's just a huge pain (apparently only from the top I've now learned) to access the bracket's bolts and a pain keeping the bracket out of your way. Then it's a pain getting it back in place to put the bolts back in when finishing the job.

I still consider it a DIY job, just one that sucks and hope to never have to do again in the future. In my case, I found my car did have the old style sensors. They are significantly smaller in diameter than the new revised versions. And if I remember correctly, the old style had light gray barrels while the new ones are all black.
 
#25 ·
Yes, I ignored the Sailor's advice and left my CPS in there while I had both valve covers off. I have no codes, car drives fine, sure it may drive better with new CPS, but I wasn't about to toss that chunk of money at that time due to the other costs incurred from all the work I was doing (cooling system, power steering reservoir and lines, valve cover gaskets and vac stuff under the plenum, etc).

I appreciate your sound advice here and regret not doing them or at LEAST checking them while I was in there. I'm the one who sent you the picture with my valve covers off to see if you could identify if it was the old or new style, and you said you couldn't really tell but to ask Peter, which I did, but never got a response.

Unfortunately for me I have large *** hands too.
 
#26 ·
Yes, I ignored the Sailor's advice and left my CPS in there while I had both valve covers off.
It is not any advantage to have the valve covers off. Jobs are not related although some time can be saved maybe. I use a hoist to do valve covers. Lift the car and make sure the back is aligned correctly. Especially on 6s, those 1/2 moons never want to line up correctly and stay.
 
#27 ·
Ok then good to know and I don't regret anything in that case! Man I had a ***** of a time getting the driver's side valve cover back on, clearing the cam sprocket, every time I wiggled myself in there (was using zip ties to hold the gasket in place) the cam sprocket would just lightly grab the gasket and yank it out of place by the time I got the cover where it could be situated. I must have done this process like 20 times before I was finally able to get it on, then checked it 20 times with mirrors, etc to make sure it was seated properly. So yeah, I was hoping to not do that job again for another 10 years or so, ha.

When you say you used a hoist, you mean an engine hoist and you lifted the engine a bit after disconnecting it from the mounts?
 
#28 ·
When you say you used a hoist, you mean an engine hoist and you lifted the engine a bit after disconnecting it from the mounts?
Car hoist. I use gasket maker or glue, sometimes light silicone to stick things, depends on the job and gasket material. Sounds like you put the gasket on the cover then tried to place it? I would place the gasket on the most solid thing let my gasket maker which does not make gaskets just sticks them, let it set for 10 15 mins then place the cover loose hoist the car again check everything. Start all the bolts, lift the car again to check, tighten all the bolts finger tight with a socket. Lift the car again and check, then tighten everything. I would likely use a step ladder now and again to avoid lowering the car. A hoist is the most powerful tool you have, so I always use it. I am short so even if I am doing engine work I lift the car take the wheels off and lower the car. Those 6" down makes my life easier but sometimes I raise it 6" or more, to not kill my back. You do better work when you are comfortable.
 
#29 ·
^^ Haha yup fully agree, was confusing your term "hoist" with an engine lift or something as normally people just call it a lift. In my case, I'm tall, so I find that I often lift the car just a bit and it also helps my back from not being leaned over the engine bay for hours... made a huge difference in doing this job. I only used drei-bond in the corners where the vanos mates with the engine and the half moon areas in the back. I then used the technique promoted by Sreten (M539 Restorations) to zip tie the valve cover gasket to the cover, once you get it seated, you clip them off and slowly pull them out and fiddle with the cover a bit to make sure everything's sitting even. I did go up and down a bit also doing this job with the lift, hands down the best tool in my garage!
 
#34 ·
All buttoned back up. Cleared codes, but now i have a fresh CEL after 40 miles of highway driving (doing the SMOG road protocol for Cali).

Now i have these new codes:
42 EWS - I’m having intermittent starting issues so i know this is a problem
90 Fuel Control Bank 1
91 Fuel Control Bank 2

what the hell? Car is running and driving smoother than ever before (esp after fresh plugs, coils and CPS all around).

any suggestions?
 
#35 ·
42 EWS - I’m having intermittent starting issues so i know this is a problem
90 Fuel Control Bank 1
91 Fuel Control Bank 2
The EWS is a separate issue, and if it continues post back, but lets deal with the 90 91first. You replaced the VCGs and said at least one was bad. Was there oil leaking at any spots? Was there oil in around the spark plugs? If yes to one or both then the 90 and 91 might be called expected codes. If there was oil leaking out then you had air leaking in, but even if you did not have oil leaking out you could have a ton of air leaking in. Nature of this engine with the constant vacuum in the crankcase. What that does is add fuel to the trims and makes them approach the max allowed but since you did not have codes then you could have been just under the max threshold.
So you fix all that and guess what happens the fuel trims make a fast correction to where they should be. That also is a way fuel trim codes get thrown, either hitting the max or making a large fast change. Probably what happened but maybe something got messed up.
The fix is to just clear the codes and see if they come back, if they do then something got messed up, my bet is they will not and if you inspect your fuel trims they will be normal after a 100 miles total.
EWS is a little harder to deal with but the simple and best first step is to use your other diamond key if you have one. If the problem goes then it is a key issue. In any event we need more info to help figure that one out. You will need to describe exactly what is happening on one of your failed starts. Does it not turn over, turns over but does not fire, or cranks starts and runs, but then turns off?
 
#40 ·
this time only the fault code 90 came back
There is something amiss. Just one of them makes it a tad harder but rules out some stuff that would affect both banks. You are going to have some test like fuel pressure and some other stuff, if you think that might be above your level start looking for a shop. Fuel control codes are difficult and we have had little success helping people well with them.
 
#41 ·
i am going to try driving a few more cycles and see if it sorts itself out.

i also bungled my VCG install on the driver's side bank and had a massive oil leak on the back end of the head. i pulled everything back apart and got it properly situated now.

still very odd to have a fuel control error though.
 
#44 ·
ok sounds good.

i will get through a couple more driving cycles. so far its running really strong - best its ever run. so if there's an issue with the fuel system, i cant tell performance wise so far. but i have to get it addressed so i can remove that CEL properly.
 
#45 ·
coming back around with a fresh update:

after quite a few more driving cycles, all the engine codes and errors have subsided. i think the system needed to readapt itself as you guys mentioned earlier. so i can finally put that behind me. car is running stronger than ever!


now I have a 'Check Brake Linings' error message on ever start up so I've gotta research what the possible culprits are for that...
 
#46 ·
I have a 'Check Brake Linings' error message on ever start up so I've gotta research what the possible culprits are for that...
Brake pad sensor. front left or rear right. Could be broken, but on the M5 they introduced a resistance value for the check so can be a poor connection at the plug. You can't just cut the end off and twist the wires together.
 
#48 ·
Side note: took the long weekend to do some much needed maintenance on the Wife's daily - 2010 RR Full Size Supercharged.

Upper & lower control arm bushings
Ball Joints
End Links
New pads and rotors on the front & rear axel
Cabin filters
Tire rotation
Oil change

At the dealer, this would have been thousands of dollars, good fortune being able to turn your own wrench.
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