C20XE Motronic 2.5 pinout terms-meaining!

[StefanWylde]

I'd like to know what these terms mean, from the M2.5 pinout scheme. If anyone knows, I'd be very happy if you could explain to me! The scheme is uploaded as an attachment.
motronic2.5_pinout.pdf

pin5: CFSV: t1 what does CFSV mean/stand for? also in the third section under 'volts/duty cycle etc', the term 'nbv' is used a couple of times. What does 'nbv' stand for?

next,
pin 8: Cylinder ID (CID) signal. Where does pin 8 go? How does the engine get the cylinder id? what is cylinder ID?

next,
pin 31: CID supply (HES): I'm guessing this has something to do with pin 8. What does 'HES' stand for?

[StefanWylde]

Also: I would like to know about pin 2: earth (ignition pulse)

Where does the other end of pin 2 go? Into the ignition module? How does the engine receive the ignition pulse?

Cheers!

[Ian T]

OK, here's my stab at this.

CID (Cylinder ID) is the camshaft position sensor, on the 20XE it is inside the distributor. It tells the ECU which rotation of the engine to fire on, in conjunction with the crank pulse.

HES is the Hall Effect Sensor, which is the technology used in the camshaft position sensor, essentially a piece of semiconductor material that changes its output in response to a varying magnetic field; the sensor is mounted next to a moving magnet, shich provides a pulse every two rotations of the crankshaft (every single rotation of the camshaft).

The Haynes Manual has a diagram in the back of it, which, in conjunction with this pinout will tell you everything and you'll see the sensors completely identified against pin number.

Does this help?

Ian.

[StefanWylde]

OK, here's my stab at this.

CID (Cylinder ID) is the camshaft position sensor, on the 20XE it is inside the distributor. It tells the ECU which rotation of the engine to fire on, in conjunction with the crank pulse.

HES is the Hall Effect Sensor, which is the technology used in the camshaft position sensor, essentially a piece of semiconductor material that changes its output in response to a varying magnetic field; the sensor is mounted next to a moving magnet, shich provides a pulse every two rotations of the crankshaft (every single rotation of the camshaft).

The Haynes Manual has a diagram in the back of it, which, in conjunction with this pinout will tell you everything and you'll see the sensors completely identified against pin number.

Does this help?

Ian.

I don't get it. I thought the 20XE did not know which cylinder was on top. Because when you unplug the hall effect, the car drives the same? Is the camshaft position sensor on the same plug as the hall effect or ?

[DarrenH]

pin5 is fuel tank vent valve, i.e the valve which lets fuel vapour from the fuel tank, stored the carbon canister, back into the engines vacuum hose. i dont know exactly what CFSV means,maybe carbon filter solenoid valve? in any case in every other bit of literature i have its called FTVV (fuel tank vent valve)

NBV is normal battery voltage (or nominal) so basically 12.

crank sensor only tells the ecu where the crank shaft is (in 360degrees) and how fast its spinning, as 4 stroke cycle is 720 degrees, plus there are 4 cylinders doing it, the crank sensor doesnt actually know what phase the engine is on. so the hall sensor tells the ecu when cyl1 is firing. it needs t know when cyl1 is firing in order to time the sequential injection correctly

the engine does run ok with hall sensor disconnected, but it guesses when to open the injectors. so will run lumpy or with less power/efficiency

[StefanWylde]

pin5 is fuel tank vent valve, i.e the valve which lets fuel vapour from the fuel tank, stored the carbon canister, back into the engines vacuum hose. i dont know exactly what CFSV means,maybe carbon filter solenoid valve? in any case in every other bit of literature i have its called FTVV (fuel tank vent valve)

NBV is normal battery voltage (or nominal) so basically 12.

crank sensor only tells the ecu where the crank shaft is (in 360degrees) and how fast its spinning, as 4 stroke cycle is 720 degrees, plus there are 4 cylinders doing it, the crank sensor doesnt actually know what phase the engine is on. so the hall sensor tells the ecu when cyl1 is firing. it needs t know when cyl1 is firing in order to time the sequential injection correctly

the engine does run ok with hall sensor disconnected, but it guesses when to open the injectors. so will run lumpy or with less power/efficiency

does the hall sensor effect the ignition timing in any way?

[DarrenH]

negative