crank position sensor(CPS) ring bent??

DIESELMAN3500

Veteran Member
Joined
Mar 2, 2008
Location
Norther New Jersey
TDI
2000 Jetta TDI,2006 vw tdi jetta,2003 vw beetle,2003 vw golf
hey guys, i have a jetta that just came into the garage the other day that dropped a valve on number 4. tore the head off and found piston number 4 mangled and the rod severely bent, ok no biggie seen it before just going through the motions, now here is where it gets interesting. the number 4 rod bent so bad that the piston when coming down hit the crank and the ring that the crank position sensor reads. the ring is now bent down ( now it is no longer perfectly round) in a certain spot.

My question to you is can i just heat and bend the ring back into a more round shape so the magnet will still pick up a signal or is this something that should be replaced which would mean pulling the engine to get the crank out, which i am trying to avoid.

how strong/sensitive is the crank position senor magnet? will the slightly bigger gap between the sensor and the ring at that one point effect the reading (electrical signal) to the point that it would effect the engines ability to run properly?
do you guys highly recommend pulling crank and replacing the ring? only 4 stinking allen screws but another couple hours in labor? i just dont want to assemble new engine and find out the CPS isnt reading properly.

thanks guys any input is appreciated
john
 

TDIJetta99

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Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
That's a tough one.. I had one come in that ran just fine where the sensor ring was quite beat up (long story short the guy purchased a used engine instead of replacing the rods/pistons).. I used that crankshaft in my engine and left the beat up sensor ring on it.. Turned out it ran fine until 4600rpm where it would drop signal and the car would shut down.. I'm sure if you could bend it back so the gap is relatively uniform all the way around it would run fine, but if it doesn't, it's a GIANT pain in the rear end to swap it out with the engine in the car, but it can be done.. Trans out, rear main off, timing belt and front seal housing off, oil pan off, oil pump off, main bearing caps off, lower crank enough to slip the sensor ring out and "reverse procedure to install" LOL.. I managed to change my sensor ring one night at the shop in about 6 hours, but I was mentally prepared and nobody bothered me the entire time..
 

DIESELMAN3500

Veteran Member
Joined
Mar 2, 2008
Location
Norther New Jersey
TDI
2000 Jetta TDI,2006 vw tdi jetta,2003 vw beetle,2003 vw golf
Thanks for your reply
I was thinking the same thing if I can get it back to the best circle I can get I would be good to go. I know on the international truck engines the gap tolerances are very sensitive and critical to proper running and signal transaction. Some body on here was saying that the ring is a one time use or some? Said that it deforms when torques? Any of that ring a bell. I wouldn't see that being the case but I'm not 100% sure. Like you said and know it's a pita to change and not something you want to do after a complete engine build. Engine is bare block now I just didn't want to take it out of car or trans out to do that ring but a penny now saves dollars later kind of thinking ya know. And it's just more money in bolts an seals to do it as well. Damn interference motors lol. Yet I still enjoy working on them lol

Out of the numerous alh builds I have done and bent rods etc this one takes the cake with the rod bending in both directions and crushing the piston to a pulp

John
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
Ya you can only get away with torquing them on 2 or 3 times before the beveled edge the bolts go in gets deformed enough so even new bolts won't tighten the sensor ring to the crank.. I put a used sensor ring in mine with the old bolts and some high strength locktite.. It's still holding almost 30k later, and it gets spun up to 6000rpm on a regular basis..
 

DIESELMAN3500

Veteran Member
Joined
Mar 2, 2008
Location
Norther New Jersey
TDI
2000 Jetta TDI,2006 vw tdi jetta,2003 vw beetle,2003 vw golf
hmmm, ok im going to try to bend it back tonight and see how round i can make it, though i was never any real good at making perfect circles back in kindergaten lol, hopefully i dont have to pull engine out to swap cranks but worst case scenario i guess thats the route i will go. thanks for the input and ill keep you posted.

john
 
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