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Discussion Starter #1
HI,

I am hoping you can assist me with a possible solution.

I recently had a new clutch installed on my 2006 Maserati Spyder. After the install the car has a tendency to stall when starting from a complete stop.
When I took it back to the mechanic they diagnosed a brake release error (I believe this is the Hill hold function). While i can feather the accelerator to get the brakes to release on flats, if i am starting from any kind of incline it just stalls.
When they make the adjustment to the ECU program (I can't tell you exactly what measure they are changing) the car will operate correctly until the car is shut off (seems the program resets to original settings).

I am hoping that you guys may have encountered this before and have a solution whether it is a program that will get me back on the road.

I appreciate any assistance you may be able to offer.

Cheers

Jimbo
 

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I had the same issue, it turned out to be the brake pedal switch, a cheap and quick fix.

Mine was just a straightforward failure not after any other work on the clutch.

Take it the car ran fine before?

the brake switch has 2 circuits, one for lights and one for the ECU.

Good luck
 

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Discussion Starter #3
Thanks GP79. I'll ask my shop to check out the break switch.
Yes the car ran fine before the clutch replacement.
Any thoughts on why the car would run fine after the ECU parameters were adjusted but then defaults back to original settings once the car is switched off?
Or maybe it's two separate issues that are somewhat related.
 

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If the PIS is set too tight the car will stall. If they backed it off but not enough then it will run fine till it heats up, and then it will stall.

A proper computer can diagnose the brake switch because you can read the switch status live (I did it while diagnosing an issue with my car). So you can confirm that without spending any money.
 

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I thought about pis too but wouldn’t cc detect engine about to stall and shift to neutral?
 

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Discussion Starter #7
Thanks lambertius
Would too high PSI also explain what I would describe as extremely hard downshifts?
Any thoughts on the ECU not holding updated data points? Maybe battery or ECU fuse?
 

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Can't really say if the PIS is the cause of downshifts being hard. There are a number of things that can cause problems, apparently the OEM throwout bearings have a tendency to stick and drop the clutch, as an example.

As for the ECU not holding value, I think you'd have to show me what value isn't reading/writing correctly to have any comment.
 

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Discussion Starter #9
So the value they were changing was the clutch in mm. But discussing with them today they said that wasn't why it ran correctly. They said it's after they ran a recycle test that the car ran properly until it was shutoff.
 

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Changing the clutch in mm would be the PIS for sure.

I've no idea what they mean by a recycle test however, can't help you there.
 

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lower PIS numbers making it engages sooner, larger number slower. It's usually lower PIS causes the harder shifting when unmatched. I've not had experience with hill hold failure, however... did the mechanic resolve it?
 

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Discussion Starter #12
Unfortunately not resolved yet. The shop thinks it's an issue with the TCU. I've posted another thread seeing if anyone has one for sale that will go with this car.
 

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I am pretty sure a wrecker here still has one handy (in Sydney Australia). Another guy was looking for one recently and I put him in touch, so I don't know if its still available.
 

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Discussion Starter #14
Hi gents,

Just thought I'd post an update. Unfortunately no fix yet. I haven't been able to locate a TCU.

Lambertius any chance you have a contact for that wrecker you thought might have one.

Cheers

Jimbo
 

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Unfortunately he has since sold the TCU.

Were you able to get any data off of the TCU, what they set etc?

From a proper scan tool you can observe everything from how the clutch engages (you can graph the position and see when it grabs, as well as circuit pressure and all kinds of other things), to checking if that brake switch is working. To me it sounds really odd that the hill hold feature would be the only thing to fail and it is just holding on.

Honestly, I would either get a scan tool yourself and try and share the parameters and I'll help you troubleshoot, or at least spend a bit of time with the shop and get them to fully explain what parameters they're setting and playing with so you can explain it clearly here.
 

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Maserati Quattroporte 4 Evolutione V8 silver/black advanced engine management 415 HP
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PIS should , must be between 4,8mm-5,1 mm factory setting .
You have allso the way of the throwout bearing , you can read this in live parameters .
This measured way must also written to the TCU .
I don’t know what kind of diagnosis tool they use , but it should be possible to do this .
Then they must proceed the self learning and check PIS and the way of the throwout bearing again.
Last week we have a QP5 with a PIS of 2,5 mm ,checked before by a specialist.....
 
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