# Does a cracked knock sensor still work? And is an ABA crank sensor plug-n-play?



## OstTrefftWest (Sep 28, 2002)

Getting my engine bay stripped last weekend (in preparation for my ABA block swap and new tranny), I noticed that my knock sensor is cracked from the center up through the top. However, I haven't noticed any running problems. Should I replace it?
Also, if I do replace it, is the (slightly cheaper) ABA knock sensor plug-and-play? While searching, I saw one thread suggesting that it was identical except for a longer cable -- but when I looked for the part online, I saw some information making me think that some A2s may have used a different style of connector than others. Any pointers?


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## OstTrefftWest (Sep 28, 2002)

*Re: Does a cracked knock sensor still work? And is an ABA crank sensor plug-n-play? (OstTrefftWest)*

I searched the Golf II/Jetta II forum and found this thread stating that a cracked sensor will be hypersensitive, and should be replaced for best performance. It makes sense, so I'll probably replace it -- but before yet another $50 nickel-dime thing, can anyone confirm that?
Also, since it's looking like I will have to replace it, I'm still interested in whether the ABA sensor is plug-n-play on DigiII.


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## kingofboggle (Mar 16, 2005)

a cracked knock sensor will definitely NOT work worth a damn. anyone who has any concept of how they work and what they are constructed from would never tell you otherwise.


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## OstTrefftWest (Sep 28, 2002)

*Re: (kingofboggle)*

Yeah, I wondered because I understood it to be a little piezoelectric microphone, but I didn't know whether it was good enough that it was still in contact with the block through material of the right density, or whether it had to be fully intact to do its job. Thanks for settling it! http://****************.com/smile/emthup.gif
So, Problem One solved. Now to find out whether the ABA sensor is a direct replacement.







Pic of the ABA sensor (blue plug), and both versions of the A2 sensor (green and black plugs -- one for CIS cars, the other for Digi, maybe?) for views:
























All three plugs sure look the same, but I don't know about the other specs....


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## Cyrus #1 (Sep 29, 2005)

*Re: (OstTrefftWest)*

I also read somewhere on here that the only difference is the length of the cord. Someone else should chip in and confirm or shoot that down.


_Modified by Cyrus #1 at 4:23 PM 4-26-2006_


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## 87_16v_85_8v_Scirocco (Aug 15, 2005)

*Re: (Cyrus #1)*

Yeah .. Id like to know that too.. Im needing one for my 16V right now, cause the one that was on it was toast......
If you ran without a knock sensor, and then with a knock sensor.. What would be the difference on a 16V?


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## Cyrus #1 (Sep 29, 2005)

*Re: (87_16v_85_8v_Scirocco)*

If you run without a knock sensor you are risking pre-detonation. With it you should be safe and might notice a bit more power as well.


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## OTIS311 (May 25, 2004)

*Re: (Cyrus #1)*

i will second that the color is just the wire length. http://****************.com/smile/emthup.gif


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## elmer fud (Aug 5, 2003)

I belive they are all the same sensor wise. just a note for guys with heavy cams or rally cars takeing good hits, they can make the cpu think the car is knocking. a alum spacer can help trick the sensor in to being happy. 
you would need a scan tool to see if the car is "knocking" when it isnt realy. peace FUDD


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## OstTrefftWest (Sep 28, 2002)

*Re: (elmer fud)*

My Autotech 270 won't be aggressive enough to cause "false positives" for knocking, will it?


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## redzone98 (Jun 10, 2004)

*Re: (Cyrus #1)*


_Quote, originally posted by *Cyrus #1* »_If you run without a knock sensor you are risking pre-detonation. With it you should be safe and might notice a bit more power as well.

i dont run a knock sensor, but im also running my timing at spec, 6BTDC
it seems to run just fine, but it does give a ping or two when she's hot, and its hot out.


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## OstTrefftWest (Sep 28, 2002)

*Re: (redzone98)*

I'll definitely keep mine. We got pretty hot summers here, and I like to run my timing a little advanced -- so I definitely want the safety net to back the timing down a bit when needed.


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## blacked out gti (Aug 7, 2002)

*Re: (OstTrefftWest)*

I know this is not the classified, but if you need a knock sensor or crank position sensor, I have one. email me at [email protected]


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## itschuck2c (Sep 12, 2005)

*Re: (Cyrus #1)*

Not sure on the wire length..but I know that depending on the knock sensor there are different torque settings..and according to the bentley manual its important to use the correct torque for the sensor you have.


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## OstTrefftWest (Sep 28, 2002)

*Re: (itschuck2c)*

Okay, new glitch with the sensor. There are three versions currently available — black plug, green plug, or blue plug. But my car's sensor has an off-white plug, which isn't one of the options.
I'd like to get the correct DigiII sensor (that way, I can get the correct torque spec out of Bentley), but I'm not sure which is the right one. Any ideas?


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## redzone98 (Jun 10, 2004)

*Re: (OstTrefftWest)*


_Quote, originally posted by *OstTrefftWest* »_Okay, new glitch with the sensor. There are three versions currently available — black plug, green plug, or blue plug. But my car's sensor has an off-white plug, which isn't one of the options.
I'd like to get the correct DigiII sensor (that way, I can get the correct torque spec out of Bentley), but I'm not sure which is the right one. Any ideas?


my car has the off white color too, we should replace it with the green plug, 
BTW u can see in the pic the black one has TWO key-way bump, while the blue and the green have 2.


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## blacked out gti (Aug 7, 2002)

*Re: (redzone98)*

maybe one side of the plug has 2 slots...one side has 1 slot?


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