cps and rpm sensor

[pasbogdan]

s6 aan not starting.Vag com showed codes for camshaft position sensor and rpm sensor.
I changed the rpm sensor and crankshaft position sensors with others from 2 working cars.Changed the ecu.NOTHING.....
I decided to get the car home towed.I put the car in 6 gear and let off the clutch to be abble to charge the batery.After 5km the rpm gauge the car started to move and the engine started(with my ecu,non imo).Stoped the car put his ecu back and it started again.
After a fiew days the car stopped starting again.Only thing left to change is camshaft position s. BUT:if i disconect the cam sensor on my urs4 and i operate starter the engine does not start but the fuel pump is working.At this s6 the fuel pump relay is not working(tried to change the relay).Also cecked the fuses near ecu(s4 has thermal fuses s6 normal ones)
Ecu pin40(Input from Engine Speed Sensor – G28 – V/BK – Also connected to Ch.28 in the A/C head so you can read out RPM in the A/C head) from ecu to sensor showed NO CONECTIVITY.

OE alarm?A friend started the car after closing and opening and cranking 20 times.
A diagram for oe alarm?

THX,

Bogdan

[S2central.net]

CAM sensor is needed to activate sparks.

RPM sensor is used to enable fuel pump.

So you can have fuel pumping when CAM sensor is disconnected or broken.

With CAM sensor connected - place a 5V LED across pin 2 and 0V - you should see pulses when cranking. If not then its a dead CAM sensor.

[UrS4boy]

CAM sensor is needed to activate sparks.
RPM sensor is used to enable fuel pump. So you can have fuel pumping when CAM sensor is disconnected or broken. With CAM sensor connected - place a 5V LED across pin 2 and 0V - you should see pulses when cranking. If not then its a dead CAM sensor.

I *might* be wrong Paul but I have to disagree. As far as I know, the AAN cam sensor is a necessary signal for the ECU during starting. Without that signal, the ECU will not engage the fuel pump relay, which in turn, does not energize the fuel pump or the injectors.

Here is some G40 cam sensor info (including links to a DIY replacement procedure):

http://forums.quattroworld.com/s4s6/msgs/22580.phtml

Here is some G4 and G28 crank position and engine speed sensor info:

http://forums.quattroworld.com/s4s6/msgs/20986.phtml

Here is some J17 fuel pump relay info:

http://forums.quattroworld.com/s4s6/msgs/22583.phtml

Hope some of this helps Bogdan.

[pasbogdan]

i had no 5v to cps.I cecked Ecu and it had no +.
The car started after giving+ to ecu.The fuse is ok.Is the oe alarm conected to cut the ecu +?
I have a red led from a inside switch iluminator and placed it to nr 2 pin of cps.It flashes.The fuel pump relay is operating with cps disconected(doubble cecked at s4 and s6).
Could be the alarm faulty?
Urs4boy,please add the led checking info of the css to your useful links posted.We should all agree with the fact if the fp relay is running or not with the cps disconected.
The rpm and crank sensors should also be abble to be cecked with the led,or not?They have an imput and an output.The output should make the led flash.
What tipe of multimeter should i use to be abble to read cps outputs.Mine is to slow to "see" 5v fluctuations and it is alwais showing 5v.
Thx!!
Bogdan

[S2central.net]

I can double check on my car but the logic is that cam sensor is used to determine phase of the engine for spark timing to #1

the rpm sensor is used as a gate for fuel pump activation. If rpm falls below a certain speed the ecu deems it to have stopped or stalled and so turns the pump off. This is more of a safety feature than anything else so that fuel is stopped during a shunt that stops the engine.

[pasbogdan]

I can double check on my car but the logic is that cam sensor is used to determine phase of the engine for spark timing to #1

the rpm sensor is used as a gate for fuel pump activation. If rpm falls below a certain speed the ecu deems it to have stopped or stalled and so turns the pump off. This is more of a safety feature than anything else so that fuel is stopped during a shunt that stops the engine.

Clear for me.No Cps no spark,no rpm sensor no fuel.
I changed hall and still NO SPARK!!!
Can it be the crank position sensor?(the pin,because the sensor is changed).But why the ecu stores camshaft and rpm sensors erors???

[pasbogdan]

after writing theese a friend started the car....
The car was running at iddle and started to run bad(like going out of gas)and finaly stopped.The relay was working but the fuel pump not.OK!!!No problem(i was happy because the pump was the problem).I disconected the conector of the fuel pump(the one with 4 wires in it) and measured the fp wires.The result was batery voltage.I changed the pump(with a good one) and NOTHING!!With the pump conected i measured directly on the pump.NO VOLTAGE.I dissconected the pump wires from the 2 pin conector behind the cap of fp.VOLTAGE.....Conected again and measured at the fp...NO VOLTAGE....
Conected the multimeter between + of the fp and ground of the car(to see if it has ground)...The pump started to run and multimeter showed voltage,and the engine is running again now ...WHAT THE....
Why the voltage was ok on wires but when i conected the pump it was no voltage...
How is conected the fp?the + cames from relay(is changed with one known to be good),what about-?


pfff....

[UrS4boy]

Might be the fuel pump relay (have a read on this):

http://forums.quattroworld.com/s4s6/msgs/22583.phtml

You probably should test the fuel pump by bypassing the FP relay by applying power to the downstream side of the fuel pump fuse holder (not sure which one it is for your car, for the AAN in an UrS4/S6 it is Fuse 17). Read all the way down to the bottom of this post (and click on the fuel pump testing link):

http://forums.quattroworld.com/s4s6/msgs/22623.phtml