No spark, Camshaft position sensor

rbrad6937 · Post by **rbrad6937** » 21 Apr 2012, 15:01

1996 850 Turbo,
I am looking for some help with resolving my sudden loss of spark. I pulled into a gas station last night to fill up, shut off my car and filled my tank, but the car would not restart. I had the car towed to my house so I could try to troubleshoot the issue. The fuel pump is working and I have good fuel pressure. I checked the voltages and resistance on the coil and that checks out also but I have no spark coming from it to the distributer cap. I'm suspecting the Camshaft position sensor but I'm not sure if that would prevent a spark at the coil. I am getting some weird readings from the Camshaft position sensor. I disconnected the negative battery cable and connector from the CPS. With the ignition switch turned on, I then checked voltage from pin 3 on the CPS connector to the ground post of the battery and got a reading of 12.7 volts which is what the procedure says I should be reading. I got the exact same reading of 12.7 volts on pin 2 but I'm supposed to be reading 5 volts. I checked pin 1 of the CPS and I should have a resistance reading of 0 Ohms but I get no reading at all. Am I doing something wrong? If I have a bad CPS will that prevent a spark at the coil? A new CPS will cost me $135.00 and a coil is $160.00, so I want to be sure before I spend the money. I am looking for good advice on how to proceed and Thank you in advance. Sorry for the long post.

Robert

Post by **jblackburn** » 21 Apr 2012, 16:32

Either cam or crankshaft sensor can cause a no-spark condition.

Since you've already got a voltmeter, test out the resistance reading on the crankshaft position sensor - it is just above the transmission flywheel - basically under the cam sensor. You should see ohm readings of >250 and <500 depending on the position the flywheel is stopped in.

If that checks out OK, i would be inclined to say that the cam sensor is probably the culprit, but I would suggest trying to poke around local junkyards, if there are any, to pull a used one before you spend the money on a brand new one. There's really no good way to test the cam sensor itself due to the type of electrical sensor it is.

The tests on the wires just confirm if the ECU is working as it should. Pin 1 to 3 as a ground should read 12.7; pin 2 to 3 should read 5.something.

Post by **Nevada1906** » 21 Apr 2012, 18:51

Check all your connections and wires. Make sure nothing has come loose or off.

JordanW · Post by **JordanW** » 21 Apr 2012, 22:09

Just out of curious, when you turn the key to the "on" or II position, does the check engine light come on? If it does NOT, and the bulb is not bad, it could indicate a problem with the Fuel Injection relay or wiring. This is the grey relay located on the shroud above the radiator. Problems with this relay can lead to a no start condition. Often the wiring can fail here as it is usually bent sharply.

rbrad6937 · Post by **rbrad6937** » 22 Apr 2012, 12:07

Just a quick update:
I purchased a new camshaft position sensor at advance auto parts for $116.00. Car started right up after I installed it. Thanks to all that replied to my post.

Robert

jgray850turbo · Post by **jgray850turbo** » 20 May 2012, 12:46

Appreciate you giving an update as an issue solved. Glad it worked out.