Camshaft position sensors.

louweez1, Jul 2, 3:36am
so figured out thats why my wrx wont start sometimes, my question is, do i just replace the sensor or do i need to be getting the camshaft checked!

motorboy2011, Jul 2, 3:37am
i'd check the cam is in the correct position in relation to all the other cams, I had a subaru that one of the cams was out by one tooth.

tonyrockyhorror, Jul 2, 3:39am
There's nothing to go wrong with the camshaft itself. But you don't just REPLACE the sensor. You check ithe signal then remove and clean it. An oscilliscope is your friend.

Unusual for it to fail cold though. or do you mean hot starts!

tonyrockyhorror, Jul 2, 3:40am
Presumably he's got an error code. Cam timing being out won't generate that unless it's also got a crank angle sensor. and even then only if it's specifically looking for a mismatch.

louweez1, Jul 2, 5:44am
had four codes come up, three to do with air intake which i knew.
but i have been scratching me head to work out the issue with hot starts, or lack of.
it does eventually start, was told it was the alarm but once i figured i could push start it, ruled the alarm out.
yeah i see cleaning it is the main tip. will see what i can do tomorrow.
cheers.

unbeatabull, Jul 2, 5:45am
What cars dont have Crank Angle Sensors Tony! I'm sure any car that has a Cam Sensor is definately going to have Crank Sensors. And I have seen many times before where a cam has jumped a tooth (and even lobes spinning on the shaft - teach ford right for pressing them on >.< ) that would just bring up a fault code for the Camshaft Sensor.

But yeah, If its intermittant and it is running fine when it does run I'd imagine it is just the sensor. I'd check the ring that the sensor picks up its signal from as well, but most likely just the sensor

motorboy2011, Jul 2, 5:49am
nissan rb engine only has cam angle sensor, as just one example.

louweez1, Jul 2, 8:27am
thanks.
it has no other real issues bar the random starting issues. it will eventually start but when your pressed for time its a pita

tonyrockyhorror, Jul 2, 8:32am
Hot or cold random starting issue!

unbeatabull, Jul 2, 8:33am
Thanks, I knew there was bound to be examples out there but I couldn't think of any at the time.

bigfatmat1, Jul 2, 9:09am
actually has cam and crank contained in the same sensor two outputs JS

Also op these always play up and cause starting faults! cam sensors that is. Cleaning it wont do shit

motorboy2011, Jul 2, 9:33am
how can this be, when the sensor is on the cam! to only one i have seen with an actual sensor on the crank was an rb25de neo, which had a cam angle sensor and crank. all other RB I have seen only have the one on the cam, bar the taxi spec 20/30e.

bigfatmat1, Jul 2, 10:01am
lots of cars have crank sensors driven off the cam its common practise to have the two sensors combined within the one housing. just utilises a diff amount of pick up teeth

motorboy2011, Jul 2, 10:38am
my new new learned thing of the day :)

hijacka, Jul 2, 10:39am
Meh . Fuel pump.
Reason you can push start it is the pump gets higher voltage as the alternate spins and voltage is not getting wasted on crank hence the worn fuel pump being able to flowing more due to higher current.
Replace fuel pump.

aredwood, Jul 2, 10:49am
First of all Have you tried deleting all of the saved codes and seeing if they come back! When it is running is the check engine light on! Also when you try to start it the check engine light should switch off while cranking and switch back on when you stop - even if the engine is only turning over under starter motor power. This indicates the ecu is detecting valid signals from the crank and cam angle sensors.

If you still think it is the cam angle sensor Try Unplugging it and seeing if it still starts. It will pop out of the exhaust for a bit but it should still start. Assuming the starting problem isn't actually something else. The check engine light will switch on if it isn't already. All of the Subarus I have seen have the ECU programmed so the car can have either the crank angle or cam angle sensor fail and the engine will still run. (But not both failing at the same time)

louweez1, Jul 3, 1:36am
did think of that, but the dyno has thrown me four codes of errors. number 13 is the camshaft position sensor

louweez1, Jul 3, 1:39am
yip check engine comes on and off. i am of the opinion it is the camshaft sensor. have to wait for the weather to settle now but will be removing it and cleaning it to see what happens. it is really random. will always start first thing in the morning but then just randomly not want to start. will eventually start but its a pain

intrade, Jul 3, 4:06pm
did not read all of this but do you actuarly have a error code in the log of your engine computer if not it could be the fuelpump a sparkplug etc a faulty cam sensore would show a error code. anything else like blocked fuel filter wont show a error code as that has no sensor

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