2JZ Position Sensor Voltages

[Jeff Lange]

This is for a Haltech Platinum Sport 2000, using PnP harness on a JDM 2JZ-GTE in a JDM JZA80.

Preface: Early 2JZ-GTE engines mostly used Aisan position sensors, while later 2JZ-GTE engines exclusively used Denso position sensors. They are very similar, however not 100% identical. I have the different resistance measurements from the TSRM. Toyota only sells Denso replacements.

Problem: 2JZ-GTE was running pretty well, not too many problems, running well until it melted a piston (not really relevant to the issue at hand). When we pulled the engine out, we decided that we should make sure there are no other problems, so I ordered 6 new coils, new cam position sensors and a new crank position sensor. Now the ECU is seeing erratic RPM signal and I believe is losing track of the cam, causing the engine to die under load.

I have changed the crank position sensor back to the original one that had no problems and it hasn't changed anything at all, so I feel the problem must lie with the Denso cam position sensor, however I do not have the old Aisan one lying around to swap out and test.

Ideally I would really like to scope the sensor outputs to see what the sensor is ACTUALLY doing, but I don't have a scope at my immediate disposal.

What you can do to help: Anyone ever scoped a Denso JZ cam position sensor or crank position sensor? Have any results? Voltages at various RPM appreciated.

Not sure if anyone will have this information, but if you do, I'd love to see it!

Jeff

 

[dogdrake]

You will see whatever the referance voltage would be going into the sensor but it will be in a ac square wave . The faster the rpm the higher the frequency of the wave. if you have melted pistons its probably a lean condition. Is the wires going to the sensors shielded ? If so make sure the end near the ecu is grounded good . You could be getting some sort of emi (electro magnetic interference) to your signal.

 

[figgie]

You will see whatever the referance voltage would be going into the sensor but it will be in a ac square wave . The faster the rpm the higher the frequency of the wave. if you have melted pistons its probably a lean condition. Is the wires going to the sensors shielded ? If so make sure the end near the ecu is grounded good . You could be getting some sort of emi (electro magnetic interference) to your signal.

that can not be as the Supra and most cars use a mangenetic sensor and not a hall-effect sensor. newers cars don't of course.

So the wave form should be a sine wave when captured against an o-scope.

If you ordered a new sensor, still shielded from EMI/RFI? How about the wiring?

as with any magnetic sensor, as RPM increase, the voltage will increase. Of course Hall-effect sensors do not have that issue.

 

[ml43]

have you tried messing with the gain settings to see if it stabilizes the signal?

 

[Jeff Lange]

The harness is a brand new Toyota harness, just installed in the car.

I have tried multiple settings provided to me, as well as other settings I've found myself.

You can see the RPM signal on the Haltech log here:
[size=-2](Red line on upper graph)[/size]

Jeff

 

[figgie]

Jeff

triple checked the air gap and make sure that the trigger wheel has no runout??

Also, by chance, have you taken a temprature measurement against the sensor?

 

[ml43]

The harness is a brand new Toyota harness, just installed in the car.


Jeff

when did you install/reinstall it?

before or after the crank sensor problem?


did you add/relocate/miss any ground wires

sometimes if you don't have a good ground that the harness uses to shield the reluctor signal you will have erratic crank signals

or if you add a ground that happens to be connected to the shielding some way, it becomes an antenna instead of a shield

sorry if this doesn't help, just making sure you're covering all the small bases, before assuming the larger ones

 

[Jeff Lange]

The issue was present both prior to, and after replacing the engine harness. All ground points are in their stock positions, and no wiring was modified on the harness, it was put in the way it came from Toyota.

I will check the air gap on the cam position sensor when I have a chance. The crank position sensor would be significantly harder to measure, but I may do so anyways.

I think I really need to scope the sensor output, so I can put my mind at ease.

I think that may be the next thing I do regarding this.

Jeff