Crankshaft sensor wiring?

Tiny
CHRISTA DICKSON
  • MEMBER
  • 2004 VOLKSWAGEN JETTA
  • 2.0L
  • 4 CYL
  • AUTOMATIC
  • 200,000 MILES
Okay, so here's what happened: the harness side coming from car side of harness to crankshaft sensor is messed up. I'm not even sure where or how far back it goes but it looks like it's going to be hard to trace. So, I wanted to just use butt connectors and crimp the wire, but I'm noticing some foil looking sheathing or wrap. I'm wondering what that is and how important it is. It's so fragile and thin it just keeps breaking apart. And I can't tell if I'm seeing some sort of green very thin wire or not. What's this for? And how important is it to be connected for the sensor to work? Can I get away with just connecting the 3 main wires? And if it's needed is there anything I could use in that area to substitute? I have foil HVAC tape or aluminum foil as options but I'm not sure if that's a good idea. Would appreciate some clarification on this. Thanks
Sunday, August 21st, 2022 AT 9:47 AM

11 Replies

Tiny
BORIS K
  • MECHANIC
  • 760 POSTS
Hello,

The thin foil you see is the shielding around the main wires to stop outside interference.
It is important to retain this as without the foil the ECU will receive a false signal and most like will not be able to start the engine.

You can splice in another part of harness, but I would suggest using a part of used engine harness which has the screening pre-installed. Any 3-core screened wire of appropriate length will do. The unscreened end splices should be kept as short as possible.

Please see the image below for the engine speed sensor pin out.
The black wire on pin 1 shares the ground at ECU pin 108 with both knock sensors.
See image 2 and 3.

Hope this helps.

Cheers, Boris
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Monday, August 22nd, 2022 AT 8:33 AM
Tiny
CHRISTA DICKSON
  • MEMBER
  • 138 POSTS
Thanks for your response. Would foil Matic tape be the same thing as a substitute? Or not? I'm thinking it may not work because I know foil conducts I think, right? Wouldn't that be doing the opposite? If so, that's a big no am I correct in thinking? Or would it work I've been trying to find some shielded cable somewhere but guess I may have to order some if there is nothing I can use in place of of the foil is so thin it breaks up and falls apart super easy.
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Monday, August 22nd, 2022 AT 11:26 AM
Tiny
BORIS K
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Hello,

Normal foil tape will not work. It would be best to order some shielded 3 core wire.
You could also try a breakers yard.

Cheers, Boris
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Tuesday, August 23rd, 2022 AT 12:56 AM
Tiny
CHRISTA DICKSON
  • MEMBER
  • 138 POSTS
Okay, is there a drain wire outside insulation on this harness or no?
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Saturday, August 27th, 2022 AT 3:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Hi Christa,

I just noticed you haven't been contacted for a few days. Have you made any progress? Is there anything I can help you with?

Let me know.

Joe
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Tuesday, August 30th, 2022 AT 9:20 PM
Tiny
CHRISTA DICKSON
  • MEMBER
  • 138 POSTS
Hi Joe, thanks for. Response I appreciate it. Here's where I am with this car. Like I previously said wiring from ECU to CKP harness messed up l, I've done some researching, learning and good old trial and error about the wiring and I've got it running for about 2 weeks but is currently broke down again after trying to crimp correctly with connectors didn't have it done well or correctly so trying to get it done right. IV learned this is a shielded wire and is precise with signals/ interference. Now I'm still trying to learn how sensitive/important shielding actually is (honestly I hate this VW and as soon as I get some money getting diff car!). This car is very finicky. Now outside the shielding I'm trying to figure out if there is a drain wire that runs outside the shielding? And if so, it needs to touch outside if shielding without touching any other wire, correct? Is there one? The wiring is so small it's hard to tell also can I use a wire to substitute connecting on the insulating shielding or is it important do I need top. Was looking into replacement for shielding foil but I guess there is none can't use foil or foil matic tape. Since trying to get it right car decided to stall out and battery drained at end of block so just walked home. Can I get away with just connect w, br, bl wires? Will never again buy a VW, not my fav. Thanks.
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Wednesday, September 7th, 2022 AT 11:01 PM
Tiny
BORIS K
  • MECHANIC
  • 760 POSTS
Hello,

Looking at the wiring diagram there is no external drain wire. The black wire joins in the loom with the 2 other black wires from the knock sensors on to brown/blue wire to pin 108.

Cheers, Boris
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Thursday, September 8th, 2022 AT 8:01 AM
Tiny
CHRISTA DICKSON
  • MEMBER
  • 138 POSTS
Okay, thanks for clearing that up. The car is currently stuck at park. I feel it might be a combination of things. I feel like I got this sensor right or connected decent because it's not pulling a code for that any longer. So, I think that's addressed but I turn the car on when it's okay for a second the battery light will then come on and the EPC light will come on, it'll bog down act like it wants to stall out completely, but then the majority of the time it'll smooth back out like it all of a sudden. Just recognize and goes back to smooth out some of the time. Then some of the times like this morning it just kept repeatedly actually stalling back out and then had to restart it again. Extremely rough idle. The only two codes I'm getting are the mass air flow sensor circuit low, so I just unplug that but I'm going to still should run I would think, correct? And one for the O2 sensor which makes sense because the cat on that car has been deleted it does currently have the exhaust leak. I had fixed the flex pipe and then they told me that the Catalytic Converter was clogged up because some of the folks probably went in there and clogged it up at a muffler shop. So, I had paid them $160.00 to weld and hopefully quite down the car because when I bought it, the only thing wrong with it was it was really loud because it had that tear in the flex pipe. And then I was going down the street and literally the back of the muffler blew off the car I heard it and I felt it and it got 10 times louder of course, and that is currently not off there. They said they could try to weld it back on for $60.00, they said that it looked like it was really thin the metal that maybe somebody had welded it before I'm really honestly not sure I don't know anything about welding I've never messed with that. Long story short there is going to be an O2 sensor code that's to be expected. I'm really not sure where to go from being fed up with this car honestly at this point. Any suggestions or opinions on where to go from here or welcome. Thanks
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Saturday, September 10th, 2022 AT 3:40 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Hi,

When you disconnect the MAF, what happens? By disconnecting it, the vehicle should go into a factory preset so it keeps running. Is that what happens, or haven't you checked it yet?

Also, what is happening with the exhaust? I never heard of a muffler shop purposely damaging the catalytic converter. I'm not saying it couldn't happen, but that is an odd one.

As far as the vehicle being stuck in park, do laugh, but are the brake lights working? The brake light switch is what signals the park lock solenoid to release.

Let me know.

Joe
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Saturday, September 10th, 2022 AT 7:32 PM
Tiny
CHRISTA DICKSON
  • MEMBER
  • 138 POSTS
I'm sorry I wasn't very clear. I literally meant it was stuck at a park like a public park not that it's relevant my bad. LOL well at the moment it's not running it won't say running for more than literally a second and then shuts off so can't check it. And just to clarify I have a straight pipe on the car, but the back of it blew off so it's open and loud. But it shouldn't cause it not to run. Quick question if the problem was that I didn't isolate the wires correctly and it was the crankshaft position sensor was picking up other signals are getting confused that's what that throw a code or not if that was the issue, I would think it would but I'm not positive on that. Maybe I didn't isolate them enough, the wiring is the only thing I can really think of at this point.
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Sunday, September 11th, 2022 AT 2:59 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Hi,

If the sensor is the issue, it can happen without a code. Take a look through this link:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Here is the thing, it wouldn't start for a second. I need you to pay attention to something. Does it stall when you release the key from start to run? If that is the case, we may have an ignition switch issue.

Let me know.

Joe
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Sunday, September 11th, 2022 AT 5:25 PM

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