Stepper Motor questions.

[Big Al.]

Quick questions guys and girls,

When you take out the SM for a clean, and it's unplugged should the center spindle slide in and out, (ooh err) or does it appear fixed in position.

If it is fixed when unplugged, will it free up when I plug it in?

BTW mine doesn’t slide but appears fixed when unplugged.

[HarryW]

Mines pretty fixed in one position when I take it out to clean it, as a stepper it has distinct positions i.e. it steps so does not move in a linear fashion so as you can slide it back and forth AFAIK .
Mine must work as I have no idling problems, you can hear it sometimes when you shut down, if you listen you can hear a mechanical wirl type noise as it resets.

Harry

[Big Al.]

Thanks HarryW, confirms my suspicions.

My original reason for asking was, I received an email via one of the TVRCC groups from a newbie with tick over problems. I suggested the he cleaned the stepper motor in the first instance.

Another member then suggested the same, but added that spindle should move in and out freely. I thought that this statement was incorrect.

[TeGriffic]

Doesn't in move electrically ? Mine never moving but cleaning it cured the idle problem.

[Big Al.]

TeGriffic said:

Doesn't in move electrically ?

My point precisely, OH

[streaky]

I came across this procedure to fully retract the Stepper Motor plunger prior to removing the Stepper Motor for cleaning:


To retract the Stepper Motor plunger prior to removal for cleaning:
* With ignition OFF, disconnect electrical plug from Stepper Motor.
* Switch ignition ON, do NOT start engine.
* Count to 10 and reconnect Stepper Motor.
* Switch ignition OFF.
* Count to 10 then disconnect Stepper Motor.
* Switch ignition ON, do NOT start engine.
* Count to 10 and reconnect Stepper Motor.
* Switch ignition OFF.
* Count to 10 before unscrewing Stepper Motor.


Clean with 'carb cleaner', allow residue to evaporate and lightly lubricate with 'WD40', 'Redex' or similar. Seal the threads with 'Loctite' or similar and replace the crush washer if it's past its best. I used PTFE tape (plumber's tape) on the threads instead of locking compound so as to get an air-tight seal. Replace the Stepper Motor and tighten to a torque setting of 13-16 lb ft (17-22 Nm).

And this procedure for resetting base idle:


1. Switch on ignition, do NOT start engine.
2. Count to 10.
3. Disconnect electrical connection to Stepper Motor.
4. Switch off ignition.
5. Count to 10.
6. Reconnect Stepper Motor.
7. Repeat steps 1 to 6.
8. Repeat steps 1 to 4.

DO NOT RECONNECT THE STEPPER MOTOR AT THIS STAGE.

The Stepper Motor should now be in the base idle position (ie. fully extended) and the by-pass valve will be fully closed.

Start the engine and adjust the base idle speed to 750 rpm +/-25 (for manual transmissions).

Switch off ignition and reconnect Stepper Motor and restart the engine. The idle speed with the ECU controlling the Stepper Motor should settle at 900rpm +/-50 but may rise above this from time to time.


When I cleaned the SM previously, I didn't follow the above (I didn't know about it), so I'm going to try it to see if my elusive idling problem goes away.

Count 'seconds', a tip here is to count "Mississippi one, Mississippi two, ..."

Usual disclaimers, YMMV.

Streaky

[donatien]

streaky said:

Count 'seconds', a tip here is to count "Mississippi one, Mississippi two, ..."

Or just use the seconds hand on your watch

Nice tip though - might give that a try next time

[jigs]

Streaky - don't forget to 'put your left leg in, put your left leg out, etc. etc. and shake it all about.'

Seriously where did you get that procedure from?

>> Edited by jigs on Sunday 28th September 14:02

[streaky]

jigs said:

Streaky - don't forget to 'put your left leg in, put your left leg out, etc. etc. and shake it all about.'

Used to do that when I was an undertaker's assistant .

jigs said:

Seriously where did you get that procedure from?

Whisper it ... a page about Morgans.