Stepper Motor problems

[meeko]

Can anyone tell me if there should be any play in the stepper motor? The part you clean which presumably moves in and out has a little play from side to side - is it faulty? My car has a mind of it's own when ticking over. Sometimes 900rpm, then 1200rpm, then hunts and eventually stalls. I don't wann buy a new one if it's not faulty...

[Tobs]

Mine also moves from side to side.... or perhaps I should put that another way - my stepper does wobble a bit.....(not sure if that sounds any better!)

My idle is OK - does wander up and down a bit - but less than 100rpm I'd say. Its my fuel economy I'm more concerned about at the moment!

Toby

[meeko]

I let my Chim warm up and while idling I disconnected the stepper. It made absolutely no difference whatsoever! I wonder whether it is dead. It also seems to miss on a cylinder or two with a very small throttle.

[Tobs]

I also disconnected mine when warm and idling - didn't seem to make any difference either (although my idle is OK at the moment anyway). If you take the stepper out and turn the ignition on it *may* move, also when you turn the ignition off it also *may* move. I say *may* because I have tried this a few times and have seen it actually move once - the other times it just seemed to vibrate (or not do anything at all)! So this test is a bit inconclusive to say the least! My idle is OK at the moment though so I assume my stepper is OK too.

Does sound as if your stepper is not working though if the idle is moving around with and without the stepper connected. Is the connection OK?

Have you checked the stepper by measuring the resistance of its coils? There are 4 connections on it to two coils internally, so the resistance across each pair of terminals should be around 50 Ohms I think. See the bible for more info.

Toby.


>> Edited by Tobs on Wednesday 23 November 13:51

[meeko]

Thanks for the tip. Will test this evening. I've actually ordered a new one anyway as I'm sick of driving my dream car when it runs like my old mk1 fiesta!

[tafford]

I'll be interested to see what difference your new stepper makes - mine hunts like yours sometimes, other times it's fine. My stepper is clean and I've never managed to trick it into moving when turning the ignition off and on when it's out.

[rfisher]

I have a fault code reader for hire if you want to try it.

May save you some time and money tracing running problems.