can't get my car to start and I've narrowed it down to the cam angle sensor

[jonheslop]

Here's my situation...I can't get my car to start and I've narrowed it down to the cam angle sensor. This is on a 91 turbo by the way. When I test the wiring it seems fine. There is 12v of power and a good ground. The black wire reads 5v every half a turn of the cas but the white wire doesn't read 5v every quarter of a turn like it's supposed to. That is the rpm signal correct? Anyways, I have used three different CAS's and none of them test right. Am I testing it wrong or do I just have bad luck with my used parts? Is there any other testing procedure I am overlooking? Thanks for the help. Jon

 

[Boosted98gsx]

Replace it with one you know is working, and if that doesn't solve your problem you know it wasn't the culprit.

 

[jonheslop]

well, I don't have any that I know work. That's why I've been buying them from people, but none of them I buy work. I don't want to shell out 300 bucks for a new one unless I know it's the problem. I guess the real question I'm asking is if I'm doing the testing properly. I only heard this test from one person so I don't know if it's right or not.

 

[project_tsi]

If you've been buying them left and right from people and it still doesn't start, its more than likely not the culprit.

See if you can swap in another ECU to try out.

 

[jonheslop]

I'm going to try a new ecu eventually but can someone tell me the correct way to test the cas.

 

[steve]

The ECU pulls the signals up to 5v. The CAS pulls the signal to ground as the sensor rotates. If you unplug the CAS and still don't see 5v on the two signal wires then the wiring or ECU are damaged. If you do see 5v with the CAS disconnected then the CAS is bad.

Steve

 

[jonheslop]

Got It

 

[Larry L]

Maybe its as easy as being 180 degrees out.

 

[steve]

Maybe its as easy as being 180 degrees out.

If he was seeing both the crank and cam signals from the CAS it might be a possibility but the OP clearly says that one works and the other doesn't. That has nothing to do with the the CAS being in or out of phase with TDC.

Steve

 

[jonheslop]

Steve is right, I have the sensor out when I'm testing it and am rotating it by hand. So being 180 out is not even in question here.

 

[jonheslop]

It ended up being a bad wiring on the harness. The result is that the test I got from these forums was wrong so be careful what you are reading. Make sure it's a reliable source.

 

[steve]

It ended up being a bad wiring on the harness. The result is that the test I got from these forums was wrong so be careful what you are reading. Make sure it's a reliable source.

Could you be more specific just in case I posted some incorrect information.

Steve

 

[jonheslop]

http://www.dsmtuners.com/forums/showthread.php?t=231608&highlight=cas+test


The test for the cam angle sensor is not correct on the above forum. For the most part it is a good reference but it is not complete and caused me to have a serious headache for a month. I would appreciate it if a moderator get that forum removed so nobody gets confused. Here is the real test...

First you need to remove the cam angle sensor plug from the sensor itself. You have to test that first. You will see four wires on that plug. There is a thick black wire, thin black wire, thick red wire and thin white wire. Put the ignition in the on or run position. First you need to test the thick black wire. It should have continuity with the ground. You will need to test this with a multimeter. One end on the black wire and one end to the ground and see how many ohms show up. It should be something, meaning .1 to 20 to whatever, just not 0. Then you need to test the red wire. It should have full battery voltage meaning 13v or so. Next test the thin black wire. It should read 5v. The thin white wire should also read 5v. Now you need to remove the sensor and plug it in. Place the sensor in the top dead center position. Tap into the thin black wire and watch your multimeter. Slowly spin the sensor and make sure that it goes between 5v and 0v four times per revolution. Now tap into the thin white wire. It should go between 5v and 0v two times per revolution. Also notice that the injectors should loudly click or fire while you are spinning the sensor. If all of this tests out then your cam angle sensor is fine.

 

[DirtyBirdRacing]

Cool, thanks for not leaving us hanging.

Bill