750il Crank sensor replacement?

[bavdrifter21]

Hey everyone I have been reading some of the threads in this part of the forum to find out more about the 750 with the v12 cause I am looking for one that is for sale that a 750 owner wants to get rid of cause he can't care for it anymore. But this car needs a crank sensor and a new brake line for the rear.
How bad is a crank sensor replacement, Being a v12 I imagine its probably something very difficult.
oh and the car is being sold for $1200, which from reading some other threads. I guess buying a BMW V12 for under $6000 is a very bad idea.

Any thoughts comments? Am I a fool to consider buying a 750il

[shogun]

the questions are:
which M70 engine, prefacelift or facelift?
which CPS, the one for cylinder row 1-6 or 7-12?

Here you see http://s71.photobucket.com/albums/i1...urrent=6-3.jpg
the big toothed wheel on the crankshaft, at 2 o' click on the left besides the belt damper piston you see one. That is the 'easier' one to change , and at 5 o' clock you see the second one. For that you have to remove the surrounding parts, and you have to loosen the bolts of the power steering pump, push it backbards towards the firewall and THEN, you can pull it out.
Side view from the power steering pump side, you cannot see it behind:
http://bmwe32.masscom.net/sean750/en...M70/Image9.jpg
power steering pump removed and you see the big hole on the left, that was where it was fitted, tha actual sensor you see hanging at the bottom of the pic

http://bmwe32.masscom.net/sean750/en...ldM70/Dsc01377[1].jpg

Here you see the brackets for 2 and 5 o'clock sensors behind the crankshaft
http://bmwe32.masscom.net/sean750/en...ldM70/Dsc01378[1].jpg
http://bmwe32.masscom.net/sean750/en...ldM70/Dsc01373[1].jpg
both installed
http://bmwe32.masscom.net/sean750/en...0/Dsc01750.jpg
http://bmwe32.masscom.net/sean750/en...0/Dsc01751.jpg


So, you can imagine what has to come out of the engine room before you can lay your hands on the sensors.
For a beginner I would say, 1 day job.

[bavdrifter21]

Well there are no good pictures of the car, But here is the ad which has a few good pictures. so to get to the crank sensor you have to pull the engine basically? or am I just talking stupid.lol. link to the ad http://maine.craigslist.org/cto/1367131794.html

[shogun]

No, you do not have to pull the engine, the pics I just showed are that you can see where these sensors are, because with the installed engine you cannot see them.
Airbox has to come out, water radiator, fan clutch, belts etc.
but the engine stays in the car, you just need enough space to get there, and probably from below, so you have to remove the plastic mud guard under the engine too.
Well, when you have the car you will see and understand.

But the question is why?
2] needs a crank sencer


if the crank sensor does not work, the engine will only run on 6 cylinders. Does he assume that is the cause? If so, why does he not repair it? I would not pay for a car such money if it runs only in limpmode. There are some people on this board which are trying to get the cars running, since quite some time.
You can sink a lot of more money in such a project, that is not a simple 318 engine.

[bavdrifter21]

Yeah I understand that I could sink alot of money into this car as a project. I was mainly looking for a lower mileage BMW and a 4dr basically and the chance to own a top of line model BMW. My 318 has been having tons of issues and has some rust out as well So I was thinking about looking at this to see if it was any better. I like that the engine can run on 6cyl's thats nice. I am definetly going to find out more about this car and maybe take a look at it. But I do apperciate your help shogun. I would like this car and I will seek more information about it and its repair history and ownership.

[todor]

Old thread, I know. But I just wanted to mention that I tried replacing the top CPS without removing the fan... big mistake. Wasted many hours trying. I'm sure it's doable (someone had posted that they did it that way), but it's a ridiculously difficult job. Just remove the fan and the shroud and you get a much, much larger amount of space to work in. I removed the fan and the shroud in a few minutes (using a Chinese fan clutch tool for about $20).

[shogun]

Some additional info: on E31 850 https://www.bimmerforums.com/forum/s...or-Replacement videos on E31
https://www.youtube.com/watch?v=axdCIQS8gJw part 1 https://www.youtube.com/watch?v=-9IJECLwmKc part 2
Replacement is shown in detail in the Bentley repair manual from page 120 section Ignition System https://www.bimmer-service.com/bmw-7-e32/ excerpt:
Crankshaft position/rpm sensors on M70 engine (arrows) mounted on front timing chain cover. Upper sensor is for DME 1, lower sensor is for DME 2.
Disconnect crankshaft position/rpm sensor harness connectors on M70 engine for right bank (1) and left bank (2) of cylinders.
On M70 engine: When replacing DME 2 sensor (cyl. 7-12), components listed below must be unbolted to gain access to lower sensor. Once all components have been unbolted and carefully set aside, rotate crank pulley/vibration damper so that gap in toothed wheel aligns with sensor mounting bolt.
• Remove bolt and sensor.
• Remove alternator cooling duct.
• Remove power steering pump pulley.
Remove power steering pump mounting bracket and pump. My comment: PS pump no need to completely remove, just loosen the bolts that you can move it a bit for sensor 2. Remove PS pulley, belt, PS pump holding bolts. Push PS pump towards driver side and remove/replace sensor at same time.
Tightening Torque: Crankshaft position/rpm sensor to mounting bracket......................7 ± 1 Nm (62 ± 9 in-lb)
• Air gap (sensor distance from toothed wheel).............1.0 ± 0.3 mm (0.04 ± 0.01 in.)

Measure the new CPS ones from Standard after installation, Bentley page 120-10 shows:
Crankshaft Position/rpm Sensor Specifications
• Coil resistance (approx.) @20°C
M30/M70 engine....................................... 540 ± 10%
M60 engine ........................................ 1280 ± 10% Important: THIS is WRONG!!!! also the M60 CPS has 540 +- 10%, Bentley revised that later
• Air gap (sensor distance from toothed wheel).............1.0 ± 0.3 mm (0.04 ± 0.01 in.)