Replacement Stepper Motor

[AusVeloce]

Hi all,

I have a 2008 Corsaro Veloce that has an erratic idle and I suspect the stepper motor is the cause. I have removed and cleaned it but still running erratically. Does anyone know whether you can purchase a replacement stepper motor separate from the injector frame?

[morini_tom]

Interested in this post as mine isn’t behaving as well as it did either.

It’ll almost certainly be the same as fitted to something else. Are there any identifying manufacturer or part number marks on the motor once you’ve removed it?

How did you get it out, out of interest? I’ve not tried myself but have read they can be hard to get out of the injector frame

[Tinker]

I think that I read that a some model Ducati stepper is the same. If I get the same fault I would try and split the stepper from the housing. As far as I can tell the motors are pretty standard the differences are the housing and the piston on the shaft end

[AusVeloce]

The OEM unit is marked as IB06/00 and S3496. I believe that the same units are used on some Ducati's. As part of the test yesterday I took off the air box cover, started the bike whilst is was hot and it immediately went to 2000+ idle. I then placed my finger over the stepper motor breather and the bike settled back to a 1400 idle. Remove my finger and back to 2k+ so on that basis I suspect the stepper motor is the cause. I have emailed Magnet Marelli so just waiting on a response.

Am I correct in assuming that the lambda sensor is the only one that would be linked to the stepper motor operation i.e. data from the lambda is used by the ECU to determine when the stepper motor should operate?

[AusVeloce]

Re removing the stepper motor from the injector frame it's just 2 torx head screws so not difficult. My understanding is that it's not possible to remove the actual stepper motor from the casing but would be interested if anyone has successfully done that.

[Tinker]

Lambda isn’t linked to the stepper operation but if the co is too far from stoic and the idle bypass is off the stepper will be trying to bring it back to normal tickover by allowing more or less air into the engine. Normal (on other bikes) the stepper closes fully when ignition turned on and then opens up a little and then hunts to find its set tickover. If anyone has messed with the throttle stops or not balanced the throttle bodies correctly it may struggle to get the target tickover.

[Tinker]

If anyone has a duff one they could send to me I could see if it’s possible to get them apart!

[AusVeloce]

Update - assuming it was a faulty stepper motor I was able to source a second hand one from the UK and it arrived today (Aus$550, ouch!). Fitted the replacement stepper motor and to my dismay the problem still exists i.e. bike still idling way too high at 2000+. Same situation as before whereby if I cover the stepper motor inlet hole the bike returns to the normal idle speed of 1200, uncover the inlet and back to 2000+. Assuming it's unlikely that both stepper motors are faulty I will now try to track down whether there is a electrical issue e.g. damaged wire on the input for the stepper motor.

Very frustrating.

[morini_tom]

Have you connected to the bike with a laptop and diagnostic software?

You can do so with freely available GuzziDiag software, and a cheap to buy diagnostic lead.

With this you can as a minimum reset the Throttle Position Sensor zero point, but you can also actuate and (I think although I have never needed to) adjust the stepper motor position.

[AusVeloce]

Hi Morini Tom,

I had already used JPDiag to re-set the TPS and that didn't fix the issue. Just to add some more confusion to the mix, I had a spare ECU that came with the bike so I installed it and the bike is now idling at 1400 so not sure why that would have made any difference but I'll be taking the bike out this week (weather permitting) so here's hoping.

[Tinker]

One ecu might be set closed loop and one might be open loop not using oxygen sensor for mixture

[AusVeloce]

I am running a Power Commander 3 and recently had the bike dynoed as it was running way too rich. Prior to the dyno it was running at 10lts/100km and post dyno it is now 6lts/100km so vast improvement with the added benefit that the bike doesn't constantly have a petrol smell.

Based on what I have seen so far I suspect it is a intermittent electrical fault somewhere in the wiring connected to the ECU. Lucky I love the bike because I am fast running out of patience.

[roofus]

i had a similar problem 2007 corsaro ,mine wouldn't idle stable , using tune ecu with the engine running the tps would bounce all over the place ,i replaced the loom inside the air box but no change ,so with the help of a auto electrician he found that there was a bad tps ground in the loom from the round connection outside the airbox ,so he grounded it from there
im not sure if the stepper has its own ground tho