Technical Starting issue

[Zardo]

Hi
as seen in the video, it takes about 8 s for the starter motor to receive the voltage with the driver actively holding the key in the "start the engine, will ya" position. Which means the ECU seems to be waiting for something to "clear" in order to safely sent current to the relais which feeds the starter motor. Now, which sensor signals would impede the ECU from engaging the starter motor? There must be some algorithm for it to go through.

I asked ChatGPT about this

In a Fiat 500 POP 1.2 with the Dualogic transmission, the ECU (Engine Control Unit) checks multiple sensor signals and conditions before authorizing the starter motor relay to engage the starter motor. These checks ensure the engine and vehicle are in a safe and operational state for starting. Below are the key signals and conditions typically evaluated:

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1. Neutral Safety Switch (Gear Position Sensor)​

• Purpose: Ensures the car is in the proper gear (typically neutral or park) to prevent the vehicle from moving unexpectedly.
• Signal: The ECU checks the transmission position sensor to confirm the gear lever is in "N" (neutral) or "P" (park).

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2. Brake Pedal Position Sensor​

• Purpose: Ensures the driver is pressing the brake pedal, a safety measure in automatic and semi-automatic transmissions.
• Signal: The brake pedal position sensor must detect sufficient pedal pressure.

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3. Immobilizer Signal​

• Purpose: Verifies the vehicle’s key is authorized to start the engine.
• Signal: The immobilizer system communicates with the transponder in the key via the Body Control Module (BCM). The ECU requires a valid signal to allow starting.

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4. Battery Voltage Level​

• Purpose: Ensures the battery has enough charge to operate the starter motor.
• Signal: The ECU checks the battery voltage via internal diagnostics. Insufficient voltage may block the starter.

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5. Engine RPM Signal​

• Purpose: Ensures the engine is not already running.
• Signal: The crankshaft position sensor must confirm the engine is at rest (e.g., near 0 RPM).

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6. Clutch Position Sensor (if applicable)​

• Purpose: In semi-automatic transmissions like Dualogic, the clutch position is monitored.
• Signal: The ECU checks that the clutch actuator is disengaged, which is controlled by the system itself.

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7. Safety Interlock (Door Status or Other Conditions)​

• Purpose: Ensures that other critical safety conditions (e.g., door status or hood status) are met, though this varies by model.
• Signal: The ECU may receive inputs from door or hood switches to verify safe operation.

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8. Crankshaft and Camshaft Position Sensors​

• Purpose: Although not always mandatory for authorizing the starter motor, some systems pre-check these sensors to ensure the engine timing data is available.

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9. Error Codes in the ECU​

• Purpose: Prevents starting if there are critical errors, such as a detected fault in the transmission system or ECU.
• Signal: The ECU runs a self-diagnostic and blocks the starter motor relay if a critical issue is found.

 

[Zardo]

This issue only presents itself when the car has been left standing for about 8 hours, so every day, but the mechanics couldn't recreate the issue, therefore they won't touch it.

Looks like it only occurs if cold or if some internal pressure of some system (clutch, gearbox) has diminished. I'd say could be a faulty actuator, or air in some hydraulic pressure system commanding the clutch or the gearbox (I don't know anything about how the Dualogic works, sorry). Let's not forget that the oil in the gearbox will heat up a little with driving and cool down afterwards. Maybe the problem is worse in winter time, too. So I'd focus on the Dualogic (automated clutch, gearbox).

 

[Ferniferous]

Looks like it only occurs if cold or if some internal pressure of some system (clutch, gearbox) has diminished. I'd say could be a faulty actuator, or air in some hydraulic pressure system commanding the clutch or the gearbox (I don't know anything about how the Dualogic works, sorry). Let's not forget that the oil in the gearbox will heat up a little with driving and cool down afterwards. Maybe the problem is worse in winter time, too. So I'd focus on the Dualogic (automated clutch, gearbox).

The car actually starts better in winter, weirdly.

 

[Ferniferous]

Maybe listen by the pedals while turning the ignition on

Is it loudest inside the car or under the bonnet

Right, i roped a colleague into helping me with this and annoyingly, because the weather is colder, it started fairly well. However, it did just start to click and i could barely hear it from the engine bay but it's very loud inside the car.

 

[Zardo]

Could it just be a calibration issue?

 

[koalar]

Right, i roped a colleague into helping me with this and annoyingly, because the weather is colder, it started fairly well. However, it did just start to click and i could barely hear it from the engine bay but it's very loud inside the car.

Am guessing it's going to loudest by the pedals where the body computer is

Stick with the plan of leaving it in neutral, to double check

 

[Ferniferous]

Am guessing it's going to loudest by the pedals where the body computer is

Stick with the plan of leaving it in neutral, to double check

Will do, i try it out over the next few days and report back.

Thanks for all you help so far, everyone that is, I'm really grateful

 

[Ferniferous]

Okay that's good it a standard petrol engine

The clicking is not the test procedure for Multiair system as toggled the actuators

Has it always sounded the same

The clicking sound is always the same, it just varies at what point it starts clicking. It was more predictable when the weather was warmer.

 

[Zardo]

The clicking sound is always the same, it just varies at what point it starts clicking. It was more predictable when the weather was warmer.

Are you talking about the sound at 8 s in your video, which occurs about half a second before the starter motor is engaged? Clearly, when it occurs, the starter motor is not yet engaged as there is no visible voltage drop. So that sound, maybe it's the actuator of the Dualogic?

 

[Ferniferous]

Are you talking about the sound at 8 s in your video, which occurs about half a second before the starter motor is engaged? Clearly, when it occurs, the starter motor is not yet engaged as there is no visible voltage drop. So that sound, maybe it's the actuator of the Dualogic?

Yes, that sound but normally it would click for longer and it's much louder in the car. The phone mic just doesn't pick it up.

 

[Zardo]

Yes, that sound but normally it would click for longer and it's much louder in the car. The phone mic just doesn't pick it up.

You could press the mic of your phone against a metallic structure of the car and it might pick up that sound way better...

 

[koalar]

How's it gone today, or too early to tell

 

[Ferniferous]

How's it gone today, or too early to tell

It started fine this morning....but then i forgot to park it in 'N' i just realised when i went out to try it, so i put it in 'N' and waited for a few moments, then started it. It started no problem. I'll try again tomorrow and let you know how it goes.

 

[Ferniferous]

How's it gone today, or too early to tell

So, the car has started fine again today, becuase of turning it off and leaving it in Neutral, while parked.

 

[Ferniferous]

How's it gone today, or too early to tell

So, 3rd day in a row and it's been starting fine if i turn it off in neutral. So, what does this mean?

 

[irc]

At the risk of starting a fresh round of Dualogic-bashing, j think it probably means you have a mechanical problem.
Most likely worn clutch, but could be the start of a gearbox problem - if it becomes hard to select a gear, the actuator will struggle. The fact that it's still succeeding is a good sign, but it is putting extra stress on the actuator, which will shorten its life if not sorted.

There is another possibility, although a bit unlikely...
Is your Handbrake working, and are you applying it BEFORE you turn the engine off?
If you stop the car, turn off the engine, and then apply the Handbrake, it can cause the car's weight to be held by the gearbox, rather than the handbrake, which will make selecting Neutral hard as the gearbox is effectively locked.

 

[koalar]

So, 3rd day in a row and it's been starting fine if i turn it off in neutral. So, what does this mean?

That's great

As @irc suspected it's taking several attempts to select neutral from a gear on initial start up

I think we can call this proved

It's not a common problem, it's more common to fall out gear into neutral

In the video it's in reverse, does it fail the same if it's left in first

 

[Ferniferous]

At the risk of starting a fresh round of Dualogic-bashing, j think it probably means you have a mechanical problem.
Most likely worn clutch, but could be the start of a gearbox problem - if it becomes hard to select a gear, the actuator will struggle. The fact that it's still succeeding is a good sign, but it is putting extra stress on the actuator, which will shorten its life if not sorted.

There is another possibility, although a bit unlikely...
Is your Handbrake working, and are you applying it BEFORE you turn the engine off?
If you stop the car, turn off the engine, and then apply the Handbrake, it can cause the car's weight to be held by the gearbox, rather than the handbrake, which will make selecting Neutral hard as the gearbox is effectively locked.

I'm pretty sure, that i apply the handbrake before i turn the engine off.
The only time i have problems selecting gear, is if i do it too fast and it beeps at me and i have to return to neutral, and try again. It doesn't like anything being done fast.

 

[Ferniferous]

That's great

As @irc suspected it's taking several attempts to select neutral from a gear on initial start up

I think we can call this proved

It's not a common problem, it's more common to fall out gear into neutral

In the video it's in reverse, does it fail the same if it's left in first

Yep, it fails whether left in gear or reverse.

Soooo, what's acrually broken and how can i fix it?

 

[irc]

Impossible to give a definitive answer without the car.
If I knew of a reliable Dualogic expert I would recommend visiting them. Unfortunately the only one I had any personal experience of has passed away.
A Forum member with MultiECUScan would be able to get some useful figures from the gearbox ECU, which could give an indication of clutch wear - a well worn clutch could cause this problem, as could low pump pressure and a few other things that can be read from the ECU.
As far as the gearbox itself goes, not much can be checked without removing it, but you could check the GEARBOX oil level, and look for any signs of leakage and report back.
My very strong suggestion is not to mess with the actuator, and don't take advice from anyone who isn't prepared to back it up with a meaningful warranty. There are far too many "experts" out there who should never be allowed to touch these, which maybe explains their bad reputation on here.