Stuck Crank Position Sensor (CPS) removal
10-23-2012, 04:39 PM
#1
Pro
Thread Starter
Stuck Crank Position Sensor (CPS) removal
This post includes a method for getting out a stuck CPS that worked for me.
Background:
I'm refreshing my intake and the original 25 year-old CPS was on my list of sensors to replace. I soaked the CPS with PB Blaster. The CPS wouldn't budge upward when I pulled with my arms. It turned in the housing back and forth a bit, but did not come up. I rigged an old lawnmower throttle wire around a scrap piece of lumber sitting across the firewall and looped the wire on the cable lead end of the CPS. Then I twisted the wire with a small lever (a wrench) and the CPS budged up slightly. I looped the wire the rest of the way around the CPS to get a more even pull and twisted. It came up maybe 1/4 inch total. In hindsight, maybe I should have let it soak some more and kept going with this method. Impatiently, thinking I was almost to victory, I began prying with a screwdriver at the new gap between the CPS and the housing. Of course, the top of the sensor proceeded to snap off leaving the rest of the sensor stuck in the hole.
Solutions:
On these boards, I read about folks going under the car to punch it up, or about going from the top using a dremel on the perimeter plastic to get the magnet out. Yes, I took a stab at drilling the magnet and quickly realized the futility of that.
My path:
I decided to try from the top. I couldn't figure out how to get a dremel in there without potentially damaging the walls of the aluminum housing. Instead I used a soldering iron with a small flat tip to melt and dig the plastic out around the magnet. I dug down maybe 1/4 inch. Eventually I was able to grip the magnet and twist/jiggle the magnet and some other metal cylinder that was in there up and out.
After some more PB blaster, I tried at first to tap the remaining sensor and pull with a bolt/washer/nut rig on a socket. The only thing I could pull up was wire and internal bits of the sensor. Then I sank a thicker wall hook into it and used the lumber and lawnmower wire to lever it up and out. It came out easily with the hook.
Anyway - wanted to share my experience for anyone else that might wind up with this challenge. There is hope and the soldering iron worked great for melting and digging out the plastic without damaging the crank housing.
Background:
I'm refreshing my intake and the original 25 year-old CPS was on my list of sensors to replace. I soaked the CPS with PB Blaster. The CPS wouldn't budge upward when I pulled with my arms. It turned in the housing back and forth a bit, but did not come up. I rigged an old lawnmower throttle wire around a scrap piece of lumber sitting across the firewall and looped the wire on the cable lead end of the CPS. Then I twisted the wire with a small lever (a wrench) and the CPS budged up slightly. I looped the wire the rest of the way around the CPS to get a more even pull and twisted. It came up maybe 1/4 inch total. In hindsight, maybe I should have let it soak some more and kept going with this method. Impatiently, thinking I was almost to victory, I began prying with a screwdriver at the new gap between the CPS and the housing. Of course, the top of the sensor proceeded to snap off leaving the rest of the sensor stuck in the hole.
Solutions:
On these boards, I read about folks going under the car to punch it up, or about going from the top using a dremel on the perimeter plastic to get the magnet out. Yes, I took a stab at drilling the magnet and quickly realized the futility of that.
My path:
I decided to try from the top. I couldn't figure out how to get a dremel in there without potentially damaging the walls of the aluminum housing. Instead I used a soldering iron with a small flat tip to melt and dig the plastic out around the magnet. I dug down maybe 1/4 inch. Eventually I was able to grip the magnet and twist/jiggle the magnet and some other metal cylinder that was in there up and out.
After some more PB blaster, I tried at first to tap the remaining sensor and pull with a bolt/washer/nut rig on a socket. The only thing I could pull up was wire and internal bits of the sensor. Then I sank a thicker wall hook into it and used the lumber and lawnmower wire to lever it up and out. It came out easily with the hook.
Anyway - wanted to share my experience for anyone else that might wind up with this challenge. There is hope and the soldering iron worked great for melting and digging out the plastic without damaging the crank housing.
The following users liked this post:
monkez (02-21-2023)
10-23-2012, 04:48 PM
#2
Rennlist Member
You did well ! The vital part is that you didn't damage the aluminium cylinder, by the look of it. The slightest dent or kink will ensure it is well jammed, and only very drastic measures with get it out...
Did your hook only thread into the upper plastic part ?
Did your hook only thread into the upper plastic part ?
10-23-2012, 05:33 PM
#3
Pro
Thread Starter
I initially drilled and tapped for the bolt a little deeper, so I suspect the hook point could have gone deeper. The hook was nice and fat and gripped the inside walls well. I noticed the CPS started to move a bit with a little upward force on the hook and then the CPS just came out somewhat easily at that point. I was relieved.
The whole ordeal took several hours, spent here and there, allowing soak, over the last couple days.
The whole ordeal took several hours, spent here and there, allowing soak, over the last couple days.
The following users liked this post:
UpFixenDerPorsche (02-19-2023)
The following users liked this post:
monkez (02-21-2023)
10-24-2012, 12:31 AM
#6
Rennlist Member
Very nice. Ingenious solution. That would be the Porsche Special tool 9834, CPS removal tool.
02-19-2023, 01:24 AM
#7
Pro
I initially drilled and tapped for the bolt a little deeper, so I suspect the hook point could have gone deeper. The hook was nice and fat and gripped the inside walls well. I noticed the CPS started to move a bit with a little upward force on the hook and then the CPS just came out somewhat easily at that point. I was relieved.
The whole ordeal took several hours, spent here and there, allowing soak, over the last couple days.
The whole ordeal took several hours, spent here and there, allowing soak, over the last couple days.
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02-19-2023, 07:33 AM
#9
Rennlist Member
Congrats.
This was one of the most frustrating jobs I did.
This was one of the most frustrating jobs I did.
