Thread: 525i Head
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Old 01-31-2011, 12:16 PM
robertobaggio20 robertobaggio20 is offline
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Join Date: Oct 2009
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Quote:
Originally Posted by ricks5series View Post
Thanks injunmort,
I do plan on doing everything you've mention especially purchasing a new wp and T-stat but others have also recommended replacing the cps. Since I'm limited in funds at the moment and the cps is working can I hold off and replace it at a later time?

Nope.

Sorry mate but this is mission critical. Its a real bitch to replace the cps.

Remember, there are 3 reasons why you're being asked to fix this now :

1. CPS failure is a common cause of no-start situations in the E34, and such no start situations are not infrequent, as we've all seen in the past couple of months. In order to avoid the extreme inconvenience of an unexpected and unpredictable failure, we should switch out to a new one at the earliest opportunity. [ The same goes for the fuel pump, and fuel, dme and o2 sensor relays. ]

2. The CPS connector is located under the m50 engine's intake manifold. The cps's head itself is easy to get to and unscrew on the car. You don't need to remove the engine fan to do this and you don't need to have dainty fingers. The problem is the other end of the cps...the one that connects to the wire harness. Its damn difficult to get to unless you're plastic man or you have dainty fingers...you'll find yourself removing the throttle body and the air hoses to get to it. Now that your engine has been opened up for the HG's job, you can easily change it out without any additional work.

3. A new CPS is not expensive, relative to all the things you'll ultimately be spending money on in terms of expected repairs and replacements and mid/long term maintenance. In fact, its $42 shipped, and there are 8 available, sale ends within 11 hours :

http://cgi.ebay.com/ebaymotors/Crank...Q5fAccessories


If you're not yet convinced, or you're considering sacrificing other more important things like that hot cam (more important only in your case as you've got that head out) in order to do this, well I have a temporary workaround for you even though i hate to put it out there as it might tempt you to not change it out. I did this for myself to make my life easier in future even though I got myself a new cps :

a. Remove the wire harness cps connector end of the cps from its holder (there's a stupid holder thingy under the intake manifold that keeps it in place).

b. Use a cable tie to tie the cps wire harness connector to one of the hoses that connects to the throttle body, or something in that area. I've cable tied mine to the dipstick. There is sufficient length in both the cps cable and its wire harness cable for you to drag it outwards to this point. You'll have to reroute the cable from its current "route" near the vanos head area where it is now.

There's absolutely no harm created by this to either the car or the cps as well.

c. In future, it will be way way way easier for you to both ohm out and check the cps resistances if necessary, and to change it out as well.

d. Curse the bmw engineers for making things more difficult than they have to be. Idiots.



rgds,
Roberto

Last edited by robertobaggio20; 01-31-2011 at 12:28 PM.
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