bigbear807

Hi All,
How do I test if the Magnetic Hall effect sensor in the distributor is working?
(Magnetic Reluctor) It's the 8 pointed star that sits on top of the Pick up coil.

I have a 1989 Iroc 5.0 conv. auto
Original 28k miles
Was driving fine then simply turned off. It cranks, turns over, but won't start.
Has 46psi fuel pressure to the rail, good spark at the plugs, No security light.
It will run for a few seconds if I spray starting fluid.
So, I don't think it's fuel related or ignition related or VATS related.
It seems like the ECM is not telling the injectors to fire just like this thread.
https://www.thirdgen.org/forums/tech...art-story.html

So before I buy a new distributor, I'd like to diagnose if it's the magnetic sensor.
Anybody ever tested that sensor?

sofakingdom

iTrader: (1)

If it runs, ever, at all, then the problem isn't the pickup coil.

If it runs with starting fluid, it's a fuel problem. Check inj 1 & inj 2 fuses.

bigbear807

Yes, the coil checks out good. has 800 ohms.
I'm trying to test the reluctor that sits on top of the coil.
the magnetic reluctor sends a signal to the ECM.
just don't know how to test it.

bigbear807

This is what I'm trying to test to see if it's bad.

sofakingdom

iTrader: (1)

If the car runs when you shoot starting fluid in it, that part isn't bad.

You don't need to test it. You already did, with starting fluid.

You have a fuel problem, not a distributor problem.

bigbear807

Yes, I understand what you're saying and I agree that it's a fuel problem. My point is that this sensor sends a signal to the ECM for the crank position and the ECM allows the fuel injectors to cycle at the proper time. so, if this sensor is bad, then the ECU won't send the signal for the injectors to open.

Drew

iTrader: (58)

LOL It also sends a signal to the ignition to spark the plugs. You have spark, the pickup is fine.

sofakingdom

iTrader: (1)

What Drew said.

If the dist makes sparks, the pickup is working.

You have a fuel problem, not a dist problem. Probably also not an ECM problem. More likely, something simple.

NoEmissions84TA

iTrader: (1)

To answer your question, you need an oscilloscope to test that coil.
Without one, you can only make resistance checks with an ohmmeter.
And if it has an intermittent problem that only shows up when it gets hot,
then a bench test will not reveal that.

bigbear807

thanks for all the help guys.
I appreciate it.

Abubaca

iTrader: (3)

Pretty sure it's a Variable Reluctance sensor, not a Hall effect.

....but it looks like we're past that.

z 28 jari

iTrader: (1)

You can measure ac volts(~2...3VAC) from pick up coil wires when you crank engine with starter.

sofakingdom

iTrader: (1)

You can test it even more easily by shooting starting fluid into the intake.

If the engine runs, the pickup is good.

Oh wait... already been there and done that.

Time to move on. Leave the dist alone and find the trouble in the fuel system.

RBob

iTrader: (1)

It can still be the ICM in the distributor. The ECM requires reference pulses from it to fire the injectors.

RBob.