Hall sensor's

[mdm123]

Need a bit of help here,

Question is what voltage the hall sensor should be producing when it’s triggered? With a 12 – 14v supply it’s only showing a few hundred mill volts when triggered.
It’s a Vauxhall Carlton GIs 12v (don't ask it was cheap lol) and it's not producing a spark.

I'm lost as I replace the ignition module with a new one, rung the wires out and they go to where they should, and got a second hand distributor but that didn’t help but I have a feeling it doesn’t work either as it simply just does the same as the original.

a quick glance on the internet suggests that I should be seeing over 4 or 5 volts.

[bertelli_1]

The hall signal should ideally go from 12v to 0v. However, a 5v drop may be enough to trigger it. Where does its 12v supply come from, the ecu?

[mdm123]

bertelli_1 said:

The hall signal should ideally go from 12v to 0v. However, a 5v drop may be enough to trigger it. Where does its 12v supply come from, the ecu?

the power comes from the ignition control box(the car is jetronic so it actuals has 3 ecu's, one for fuel, ignition and idle control), but i also took the distributor out, tested it on the bench and got the same result.

[stevieturbo]

You need an oscilloscope to test such a sensor.

[Belly954]

As Stevie has said correct way to test is with scope although to check if the hall chip is capable of switching the ignition system is to check for voltage across the outside pins if that is okay,if the middle pin is 'brushed' to an earth on the engine small piece of wire with the sensor disconnected the ht lead from the coil should produce a spark,I know this does not test the sensor but it does test the rest of the ignition system if abit crudely

[mdm123]

stevieturbo said:

You need an oscilloscope to test such a sensor.

when i said testing it in the car i forgot to point out this was using the cars electrics and manual turning the the distributor.

[mdm123]

Belly954 said:

As Stevie has said correct way to test is with scope although to check if the hall chip is capable of switching the ignition system is to check for voltage across the outside pins if that is okay,if the middle pin is 'brushed' to an earth on the engine small piece of wire with the sensor disconnected the ht lead from the coil should produce a spark,I know this does not test the sensor but it does test the rest of the ignition system if abit crudely

I've already tested the coil and ignition module and they work perfectly, although i did replace the ignition module anyway.

i realise that a multimeter will be no good if I'm testing the hall sensor in the engine with the starter motor.

what I'm really trying to find out is what voltage should i be seeing if i manually turning the distributor between air gaps on the rotor ie what should the hall sensor be switching when it on or off, should it be between 5 to 12 (dependent on supply voltage, but a digital high none the less) or is it millivolts like i am seeing.

[Simon Says]

Belly954 said:

As Stevie has said correct way to test is with scope although to check if the hall chip is capable of switching the ignition system is to check for voltage across the outside pins if that is okay,if the middle pin is 'brushed' to an earth on the engine small piece of wire with the sensor disconnected the ht lead from the coil should produce a spark,I know this does not test the sensor but it does test the rest of the ignition system if abit crudely

Yes i can vouch for your method,always works for a quick diagnosis on cars that are prone to failure of both ign mod/coil or hall sensor (VW Golf/Polo 8v)mdm123 are you earthing the dizzy while your spinning the dizzy manually?

Edited by Simon Says on Saturday 2nd January 20:55