Impulse Sensor Adjustments

[wcc]

I've had some hot starting problems in the past and after this thread:

89 Carerra Hot Start Problem

I thought I'd add the impulse sensors to my 'while you're in there' list when I do my transmission.

My first question is can these be adjusted to regain the gap called for in the Bentley manual?

The 'reference sensor' looks easy enough cause there is a set screw on the fly wheel side for lack of a better term. So do I adjust that set screw or the sensor.

But the 'Speed Sensor' looks as though it uses the teeth of the fly wheel. So can that sensor be adjusted in or out to regain that gap?

I'm leaning towards just replacing them but I'm just curious cause if they are even adjustable.

[dfink]

They are adjustable but not by the screw on the flywheel. Leave it alone. Normally the response on the board is do not touch the adjust on the sensor mount. Me being dumb and thinking I had to take the bracket off to remove the tranny did so. I therefore had the job of readjusting the sensors. Do a search an you can find the proper mm setting for the sensors. Normally the braket stays put and you just replace the sensors. If the sensor wires are cracked I would replace them, mine fell apart. Put in the new sensors and then check the gap. If it is correct do not try to change it. I worried the entire time I was putting my engine back in if it would start since I had to readjust the sensors but everything was fine so it can be done. Also remember the sensor at the top of the engine is a diagnostic sensor and is likely not connected to anything so you only replace the two sensors on the side. Oh and sit down when you check the price. Ouch.......

[JeremyD]

No easily - set the gap and torque them down.

[wcc]

Ok, I won't mess with the set screw. The gap is .8 mm and the Bentley book says to glue a .8mm thick washer on the being discarded sensor to set the gap. If the insulation is fine I'll just adjust the gap and torque them down like JeremyD said. If the insulation is bad then I'll replace them both unless there is something that I can wrap them back up in? Any ideas? Electrical tape? Hopefully, the insulation is fine cause I already looked at the price. That's why I started this thread.....

[Thrasher]

The one adjuster on the mounting bracket will actually control the gap on both. There is much detail in the archives. I searched on flywheel + sensor and reference + sensor

Since you'll have the tranny off the motor, you can actually measure the gap. A trick for those mounting the sensor in-situ is to remove the old sensor and mount a 0.8mm thick washer (I think that's the gap?) onto the end of it. Then, use the old sensor/washer to set the gap using the bracket adjustment. Then, just remove the old sensor and replace the new sensor in its place.

When replacing both of mine in-situ, I was lucky and only had to remove the sensor retaining bolts, and never touched the mounting bracket.