Glow Plug Failure and Electronic Throttle Control

[glend]

The accelerator (throttle position sensor) is pretty reliable, I haven't seen one post about one failing. It uses a small magnet (Hall Effect) which moved when you move your foot against a coil. The resultant signal is the throttle position sent to the ECM.

Auberon, my Jeep mechanic friend suspected my Flow COntrol Valve (aka Intake Throttle in the Parts List) when my ETC light first appeared. Not all years have an ETC light.

[Auberon]

No conundrum. I cleaned the hall effect device under the "go pedal" with a blow of fresh air. All other testing proves fruitless - everything is within specs.

There are little-known things such as mini meteors falling from the sky all the time (read microscopic meteorites) - microscopic bits of magnetite and they throw an erroneous reading in low-positioned hall devices as they coalesce in bands along the flux of the hall sensor as it has its own fields to attract them. They progressively become bigger magnets with a stronger field as they coalesce. They are as invasive as bulldust when a magnet is involved. Some soil types release them more from the colloidal suspension more readily than others - and that gets into soil science - not for here.

It tends to gather in one band due to the flux density of the hall device (as small as that might be) and produce an anomoly in the hall effect device. When the throttle is held within that new field for a period it produces an erroneous message. It does not mean it is faulty, just a bit confused in one part of its travel.

That is what emerged upon capture, cleaning, 400x examination.

[SAKJ]

Originally Posted by Auberon

No conundrum. I cleaned the hall effect device under the "go pedal" with a blow of fresh air. All other testing proves fruitless - everything is within specs.

There are little-known things such as mini meteors falling from the sky all the time (read microscopic meteorites) - microscopic bits of magnetite and they throw an erroneous reading in low-positioned hall devices as they coalesce in bands along the flux of the hall sensor as it has its own fields to attract them. They progressively become bigger magnets with a stronger field as they coalesce. They are as invasive as bulldust when a magnet is involved. Some soil types release them more from the colloidal suspension more readily than others - and that gets into soil science - not for here.

It tends to gather in one band due to the flux density of the hall device (as small as that might be) and produce an anomoly in the hall effect device. When the throttle is held within that new field for a period it produces an erroneous message. It does not mean it is faulty, just a bit confused in one part of its travel.

That is what emerged upon capture, cleaning, 400x examination.

Consider myself educated! Interesting.