Thread: Stepper Motor - V8 D1?

Originally Posted by PSI250

i have a working stepped motor you can have/try, i'm in S.E suburbs, VIC. Your welcome to come have it, i couldn;t give it away on other forums!

Thanks, that'd be fantastic to see if it sorts the issue - will drop you a pm and sort out the details.

The stepper motor is only really used to set the idle speed and to maintain the idle when cold.

If you can get the engine to idle at the correct speed when warm for more than a few seconds, simply disconnect the 4 pin plug from the back of it (while the engine is at idle) and leave it off. If the problem occurs again, it's not the stepper. You might find you need to use the throttle to keep the engine running at idle when cold but apart from that you won't notice the fact that the stepper is disconnected.

If needs be you can manually adjust the position of the pintle by hand to set a static idle but it's a pain to do that as it you have to screw the unit out and in again every time you want to make a small adjustment. Much easier to let the ECU do it and then freeze it in place by disconnecting it as above.

The stepper is fitted to all 3.9 EFi Range Rovers and Discoveries and is a standard Bosch unit so is used on a lot of other vehicles produced from around 1990-2000 with distributor ignition. Could well be worth a poke about in the local breakers.

Originally Posted by davew

The stepper motor is only really used to set the idle speed and to maintain the idle when cold.

If you can get the engine to idle at the correct speed when warm for more than a few seconds, simply disconnect the 4 pin plug from the back of it (while the engine is at idle) and leave it off. If the problem occurs again, it's not the stepper. You might find you need to use the throttle to keep the engine running at idle when cold but apart from that you won't notice the fact that the stepper is disconnected.

If needs be you can manually adjust the position of the pintle by hand to set a static idle but it's a pain to do that as it you have to screw the unit out and in again every time you want to make a small adjustment. Much easier to let the ECU do it and then freeze it in place by disconnecting it as above.

The stepper is fitted to all 3.9 EFi Range Rovers and Discoveries and is a standard Bosch unit so is used on a lot of other vehicles produced from around 1990-2000 with distributor ignition. Could well be worth a poke about in the local breakers.

... and the idle step up with A/C compressor cut in, and full steering lock loads, and auto trans in drive....
There is also other reasons for the stepper to play up, one of them is incorrect or out of adjustment TPS, and a dirty throttle plate etc.

JC

[quote=westonben;807035]Are you really sure the stepper needs replacing? It's quite an expensive part.

1. With the engine running pull the plug on the stepper, (does it idle better??) then turn off the engine.
2. Unscrew the stepper and then re-insert the plug (the pin should not be fully wound in as you unplugged the stepper whilst the engine was running).
3. With the stepper uncrewed into the plenum, turn the ignition on, so the lights come on (but don't start her up).

Did the pin wind itself back in?

O.k i have tried this out.
The pin tried for a second to wind back in but failed but when i turned the ignition off it wound straight back in.
I have trouble with over revving when it is cold(over 2000rpm's)but not bad when it is warm although quite slow to drop the revs at the lights so i think the stepper is faulty does this sound right.I have tried another off a spare car but is very similar in idle and at lights it occasionally doesn't drop back at the lights so very annoying.Thanks in advance Brett