Stepper motor needs replacing

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jaz

New Member
Posts
24
Hi, my stepper motor (idle air valve) needs replacing but new uns are so damned expensive. I've seen one on ebay but advertised for Rover 200 -800 etc. part number C403056730 so it says, I tried to phone the local Landrover dealer but they would not tell me what part number is fitted to my vehicle - 1995 3.9 EFI - so I guess my question is... can anyone tell me if this part will fit... it looks the same but maybe that's no clue!! Or if not, where can I grab a cheap stepper motor??
Cheers
Jaz
 
Whats wrong with the old one ? They often get the blame for an idling fault but in practice they are reliable - what is the exact fault on your car ?
 
The original fault was the engine cutting out at low revs especially when dabbing the throttle when parking etc. (it's an auto). After some advice I took the stepper off and cleaned it and there was a good improvement, although not perfect, but it went worse again after a while. So I took the stepper off again and gave the plunger a working over and loads of wd40 etc. After re-assembley it no longer cuts out but the revs don't always drop down at idle any more, varying between 850 to 1150 ish rpm normally stopping around 1100rpm at idle when warm. Think of the extra fuel on a V8!!!
Thanks
Jaz
 
Hey guys looks like you were right!! I changed the stepper motor and it still stalls... sometimes. It seems ok in neutral, but the revs drop to below stalling point when pulling up to jucnctions/roundabouts etc. and gosh does it make the steering heavy!! Any ideas gratefully received, or alternatively can anyone recommend a good landrover garage/mechaninc near Chester? The last place I took it to in Deeside I wouldn't go back to if it was free!!
 
Sounds to me like the oxygen sensors are not switching - if the black output wire on each sensor is staying at 0v and not switching from 0v to 0.8v once a second when the engine is idling,the engine ecu will try to richen the mixture to get the sensors up to 0.8v.Look around the inlet area for vacuum leaks,and the exhaust manifolds for blowing gaskets etc.
The sensors are heated with battery voltage on the red wires,via the second output from the fuel pump relay when the engine is running,they will not be hot enough to switch if they are not fed and earthed.
When you have checked all the above you can test the actual sensors by measuring the output voltage on the black wire.It should go rich - 0.8v when you rev up and go lean 0v on the overun.They should switch once a second at a constant speed - or quicker when the revs rise.If this is not happening your car will not run properly,pass an Mot or give decent fuel consumption.
 
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