Cam shaft position sensor cylinder?
Cam shaft position sensor cylinder?
All you guys out there that have changed your cams did you check that you got the cam shaft position sensor cylinder back in the same position? It’s possible to put it back in two ways, either the correct way or turned half a turn i.e. 180 degrees around.
As we weren’t 100% sure which way the cylinder was supposed to be we just took a chance, put it back the way we though it was sitting before and test started the engine. The engine started and idled fine and didn’t behave strange in any way at all. We then just assumed that we got it right and didn’t think much of it any more.
As some of you might know I’ve had huge problems with my car since I put on the turbo kit, the cams and the stand alone Motec ECU. The major problem I had was that my car was very prone to knock above 5k rpms and basically we weren’t able to make much more power than what you could get out of a stock turbo and stock cams with a stand alone ECU. We had to lower boost as well as the ignition to make the engine run safe.
Then after that disastrous tuning day we started looking into what could cause the engine to behave like this and we ruled out thing after thing and finally we thought of the little dilemma we had with that cylinder. We then checked the workshop manual and sure as hell it had a very obvious description how to get the cylinder in the correct position. This cylinder is located on the exhaust cam shaft on the opposite side to the cam gear. Under a small lid you can see the cylinder which has two vanes on it, one smaller and one larger, if you bring the engine to it’s zero mark, i.e. cylinder one in top dead position the smaller vane should point toward the front of the engine and slightly upwards toward the top bolt hole of the lid and mine was pointing in the opposite direction.
After turning it back to the correct position the car started as good as ever and so far the only thing I’ve noticed is some more tendencies of back fire when on idle or on deceleration off the throttle. I’m very careful as I presume the ignition timing could be way of now and won’t drive the car any more until I’ve had a new tuning session.
I have no idea if this could be the reason for the strange knocking behaviour but I sure hope so.
As we weren’t 100% sure which way the cylinder was supposed to be we just took a chance, put it back the way we though it was sitting before and test started the engine. The engine started and idled fine and didn’t behave strange in any way at all. We then just assumed that we got it right and didn’t think much of it any more.
As some of you might know I’ve had huge problems with my car since I put on the turbo kit, the cams and the stand alone Motec ECU. The major problem I had was that my car was very prone to knock above 5k rpms and basically we weren’t able to make much more power than what you could get out of a stock turbo and stock cams with a stand alone ECU. We had to lower boost as well as the ignition to make the engine run safe.
Then after that disastrous tuning day we started looking into what could cause the engine to behave like this and we ruled out thing after thing and finally we thought of the little dilemma we had with that cylinder. We then checked the workshop manual and sure as hell it had a very obvious description how to get the cylinder in the correct position. This cylinder is located on the exhaust cam shaft on the opposite side to the cam gear. Under a small lid you can see the cylinder which has two vanes on it, one smaller and one larger, if you bring the engine to it’s zero mark, i.e. cylinder one in top dead position the smaller vane should point toward the front of the engine and slightly upwards toward the top bolt hole of the lid and mine was pointing in the opposite direction.
After turning it back to the correct position the car started as good as ever and so far the only thing I’ve noticed is some more tendencies of back fire when on idle or on deceleration off the throttle. I’m very careful as I presume the ignition timing could be way of now and won’t drive the car any more until I’ve had a new tuning session.
I have no idea if this could be the reason for the strange knocking behaviour but I sure hope so.
If this system works similarly to another of which I am familiar, the camshaft sensor (or cylinder identification sensor) determines when to fire the fuel injectors, as they are activated on every other piston stroke.
If this sensor is installed backward, the injector will fire on the wrong stroke. Some of the fuel would have a chance to puddle, which would likely cause a lean condition and throw off the fuel metering.
If this sensor is installed backward, the injector will fire on the wrong stroke. Some of the fuel would have a chance to puddle, which would likely cause a lean condition and throw off the fuel metering.
it makes a difference. If you read the cam swap on evomotor it says which way to install. See step 31...
http://www.evomoto.com/tech_info.php...3_6&tech_id=18
http://www.evomoto.com/tech_info.php...3_6&tech_id=18
Originally Posted by Ted B
If this system works similarly to another of which I am familiar, the camshaft sensor (or cylinder identification sensor) determines when to fire the fuel injectors, as they are activated on every other piston stroke.
If this sensor is installed backward, the injector will fire on the wrong stroke. Some of the fuel would have a chance to puddle, which would likely cause a lean condition and throw off the fuel metering.
If this sensor is installed backward, the injector will fire on the wrong stroke. Some of the fuel would have a chance to puddle, which would likely cause a lean condition and throw off the fuel metering.
Ok, thanks for your answer but could it also affect ignition timing in any way? I'm desperately trying to find that this could be the cause of my knocking problems
Well, the ignition system usually depends on the crankshaft sensor to determine when to fire, so installing the cam sensor incorrectly should not affect the ignition.
However, firing the injectors at the wrong time can definitely cause a knocking problem, simply by virtue of the fact that the fuel has time to fall out of atomization and cause a lean mixture in the cylinder.
However, firing the injectors at the wrong time can definitely cause a knocking problem, simply by virtue of the fact that the fuel has time to fall out of atomization and cause a lean mixture in the cylinder.
^^^^ That guys knows better than me so I am just going to agree with him at this point... Just Kidding. Yes it would likly cause a knocking problem do to the valves being out of sync with the piston/ignition. I would think that it should also throw a big check engine light it out of phase. Just a thought.
Originally Posted by Ted B
Well, the ignition system usually depends on the crankshaft sensor to determine when to fire, so installing the cam sensor incorrectly should not affect the ignition.
However, firing the injectors at the wrong time can definitely cause a knocking problem, simply by virtue of the fact that the fuel has time to fall out of atomization and cause a lean mixture in the cylinder.
However, firing the injectors at the wrong time can definitely cause a knocking problem, simply by virtue of the fact that the fuel has time to fall out of atomization and cause a lean mixture in the cylinder.
Last edited by EVOVII_SWE; Sep 9, 2004 at 01:49 PM.
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Originally Posted by Cajun Power
^^^^ That guys knows better than me so I am just going to agree with him at this point... Just Kidding. Yes it would likly cause a knocking problem do to the valves being out of sync with the piston/ignition. I would think that it should also throw a big check engine light it out of phase. Just a thought.
Actually this is only an electrical thing so the valves could never mechanically be out of sync with the pistons and as I'm running a stand alone ECU CEL's is a thing of the past
Exactly. The cam sensor has no bearing on the mechanicals. The way it usually works is the spark plugs are fired on *every* piston stroke because the ECU fires them according to crank sensor position.
On the other hand, the cams turn only half as fast as the crank, and the ECU looks at the cam position sensor to determine when a cylinder is coming up on the intake stroke (gets the fuel). As we know, fuel injectors are fired only every 720 crank degrees. This is why the cam sensor is referred to as a CID or Cylinder Identification sensor, as it identifies which cylinder gets the fuel.
If the CID is backward, the injector sequence is 360 crank degrees out of phase, whereby computer fires the injectors just before the power stroke instead of the intake stroke. The result is the fuel drops out of mixture and just puddles on the closed intake valve until it reopens. This will almost certainly cause mixture issues and decreased power. You'll know something isn't right!
On the other hand, the cams turn only half as fast as the crank, and the ECU looks at the cam position sensor to determine when a cylinder is coming up on the intake stroke (gets the fuel). As we know, fuel injectors are fired only every 720 crank degrees. This is why the cam sensor is referred to as a CID or Cylinder Identification sensor, as it identifies which cylinder gets the fuel.
If the CID is backward, the injector sequence is 360 crank degrees out of phase, whereby computer fires the injectors just before the power stroke instead of the intake stroke. The result is the fuel drops out of mixture and just puddles on the closed intake valve until it reopens. This will almost certainly cause mixture issues and decreased power. You'll know something isn't right!
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