Cam Sensor setting woes

[Blazer406]

I got the engine at 25 deg ATDC on #1 compression stroke.... dropped the cam sensor in....rigged battery up to 12v on the red wire.... ground on the black wire... and my multimeter up to battery ground... and the + on the multimeter to the blue wire on cam sensor...... no matter where I turn the sensor I don't get the 7.5 Volts like the "how-to" says....

I have double checked.... I'm getting 12v into the cam sensor plug at the red wire.... ground into the plug on the black wire.... and like .007 v out on the blue wire......

What gives....?

Any ideas?

 

[turbo nasty]

Which way are the wires facing on the sensor?

 

[Blazer406]

Which way are the wires facing on the sensor?

The window on the wheel is looking right at the #1 cylinder.... and the cap wires are as well.... I have the engine on the stand... so I have room to work.... and I can rotate the sensor near 360 deg... and still only get like .0007 volts...... I do see the voltage drop to near 0 when the window is approximately where the wires are.... but still.... the "how-to" says 7.5 volts......when turned full clockwise....

 

[KevinB]

Kind of a dumb question, but what setting do you have the voltmeter on?

 

[Blazer406]

I see a similar thread..... this guy had the same issue.... I must be missing
something.....

cam sensor adjustment with cam sensor not in car....

 

[Blazer406]

Kind of a dumb question, but what setting do you have the voltmeter on?

It is an autorange... Fluke..... I've tried manually setting to the correct range too...... no dice.

 

[KevinB]

It is an autorange... Fluke..... I've tried manually setting to the correct range too...... no dice.

Yeah, when I read that you saw .007 volts...I was thinking you had the meter turned up on one of the higher power settings. I've done that before:redface:

 

[turbo nasty]

Check and make sure the tab on the reluctor window deal isnt shared off/ben

 

[Blazer406]

Check and make sure the tab on the reluctor window deal isnt shared off/ben

Looks fine.

 

[Blazer406]

See pic below. When I hook up my volt meter instead of the led bulb (Thanks to CliffyC for pic and schematic) ... I get 12V (my red wire is hooked to a car battery... not a 9v battery) between the blue wire and the red wire. I get the 12V when the window is lined up with the sensor..... I get near 0 everywhere else......

 

[notacarlo]

Let me ask this question.

I assume the motor is on a stand with a battery hooked up to it.

Is the motor grounded to anything other than the negative post on the battery?

Shouldn't the assembly be grounded to something a little more substantial?

Like a set of Jumper cables to something else for ground?


Just a thought.

 

[Blazer406]

When I hook 12V to the red on cam sensor cap........ neg side of battery to black wire on cam sensor cap...... and + on volt meter to blue wire on cap.... and - on voltmeter to neg side of battery......

I get .0007 volts anywhere that the window isn't lined up with the sensor.... and near 0 volts when the window is lined up....

 

[Blazer406]

Let me ask this question.

I assume the motor is on a stand with a battery hooked up to it.

Is the motor grounded to anything other than the negative post on the battery?

Shouldn't the assembly be grounded to something a little more substantial?

Like a set of Jumper cables to something else for ground?


Just a thought.

I am using a set of jumper cables....the negative is grounded to block... and wire is hooked from there to black wire in cam sensor cap connector.

Battery positive is only hooked to red wire on cam sensor cap....

 

[Blazer406]

When I try and use this method below.... I get the .0007volts on the blue wire when the sensor is anywhere BUT lined up with the window.... otherwise...... 0 volts.

 

[Blazer406]

Here are the directions from GNTTYPE....

1. Measure on a piece of masking tape and mark it at 1.45" and tape it to the Balancer at 0 degrees.
2. Bring #1 to TDC and then grab the intercooler fan and rotate the motor to your mark (25 degrees ATDC). This takes a little patience and muscle. You can try bumping it with the starter, but I'm never very successful at that.
3. Back probe the middle wire of the cam sensor (marked B and normally blue) with a voltmeter. Turn the key ON, but leave the engine OFF.
4. Loosen the sensor with a distributor wrench or a wobble socket and extension.
5. Rotate the sensor full CLOCKWISE. The voltmeter should read 7.5+ volts.
6. Slowly rotate the sensor COUNTER clockwise until the voltage drops.
7. Secure the sensor at the instant the voltage drops


IMHO... this contradicts the directions in the previous post.....

Compare step 8 in post # 14.... to steps 5 and 6 in post # 15.

Am I missing something?

 

[RmvBfrFlght]

I am using a set of jumper cables....the negative is grounded to block... and wire is hooked from there to black wire in cam sensor cap connector.

Battery positive is only hooked to red wire on cam sensor cap....

A pull up resistor is required on the sensor signal wire (blue). The ignition module usually provides this. Place a 1K-ohm to 4.7K-ohm resistor from the +12 to the sensor signal wire.

Can also use the LED set up shown above. That too will provide the pull up for the signal line. Note that a 12V LED has current limiting resistor built in.

The reason this is required is that the signal will not provide a voltage. It is only capable is sinking current. So need to give it some voltage (current limited) to have the signal go high.

RemoveBeforeFlight

 

[Blazer406]

A pull up resistor is required on the sensor signal wire (blue). The ignition module usually provides this. Place a 1K-ohm to 4.7K-ohm resistor from the +12 to the sensor signal wire.

Can also use the LED set up shown above. That too will provide the pull up for the signal line. Note that a 12V LED has current limiting resistor built in.

The reason this is required is that the signal will not provide a voltage. It is only capable is sinking current. So need to give it some voltage (current limited) to have the signal go high.

RemoveBeforeFlight

By George.... I think you might be onto something..... will do this tonight....

 

[mikestertwo]

A pull up resistor is required on the sensor signal wire (blue). The ignition module usually provides this. Place a 1K-ohm to 4.7K-ohm resistor from the +12 to the sensor signal wire.

Can also use the LED set up shown above. That too will provide the pull up for the signal line. Note that a 12V LED has current limiting resistor built in.

The reason this is required is that the signal will not provide a voltage. It is only capable is sinking current. So need to give it some voltage (current limited) to have the signal go high.

RemoveBeforeFlight

+1 The cam sensor is a switch, not a voltage source.

 

[Blazer406]

Can someone confirm that my post 15 is correct?

Turn clockwise.... monitor voltage... should read 7.5volts..... turn counterclockwise until voltage drops to 0... at that exact point... lock the sensor down.

 

[Blazer406]

A pull up resistor is required on the sensor signal wire (blue). The ignition module usually provides this. Place a 1K-ohm to 4.7K-ohm resistor from the +12 to the sensor signal wire.

Can also use the LED set up shown above. That too will provide the pull up for the signal line. Note that a 12V LED has current limiting resistor built in.

The reason this is required is that the signal will not provide a voltage. It is only capable is sinking current. So need to give it some voltage (current limited) to have the signal go high.

RemoveBeforeFlight

I knew I should have paid more attention in electronics class in college.

Well... I put a resistor in.... and put the + cable from the voltmeter to the blue wire.... and the - cable to engine block ground.... and presto..... I get 12V anywhere the sensor is rotated except when the window is lined up..... when the window lines up I get like .11volts.... (probably because of the voltage coming thru the resistor......)

I think I have it.....

I did adjust per the directions on GNTTYPE.... roll the sensor clockwise...then start rotating counterclokwise... until the voltage just drops off.... then lock it down.....

Engine should go in tomorrow.