Start/Stop Issue Advise needed, Belt Tension?

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lesliepg
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Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 12 Dec 2018, 09:54

Hi Guys,

I have an issue with my 2012 1.6 e-hdi DS5. My car has Start/Stop system, when I come to a stop the engine stops and goes into ECO mode (Green ECO Light on) when I lift the brake I hear a squeal then the engine doesn't restart. I have to put the car back into netural and press the engine start button to get the engine started again. I have replaced the battery with a new one (AGM) and is fully charged.

From my own diagnostics, The Start/Stop system on this Citroen 1.6 e-hdi uses a BAS Reversible Alternator to restart the engine. I have noticed that one of the aux belt tensioners is a bit noisey and seems to be bouncing a bit more than usual. As I believe the restart of the engine in ECO mode relies on the (Belt Assisted Starter) alternator, if my tensioners and belt are on it's way out that would explain the squeal when the engine tries to restart from ECO mode. The BAS alternator doesn't seem to get enough grab on the belt to restart the crank and is possabliy slipping.

Cant think of any other reason why I would hear the squeak on restart, as the cold engine starter is not used in ECO mode. Cold starter motor is OK as it's starting the engine just fine and the battery is being charged by the alternator.

Can anyone confirm these findings? If this is the case I will just go ahead and purchase the aux belt tensioner kit.

Not likely to be anything else do you think guys?

Many Thanks for reading

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GiveMeABreak
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by GiveMeABreak » 12 Dec 2018, 10:34

Can you pop up your VIN up so we can determine complete specifics fitted and I’ll get back a bit later.

I can say there are specific conditions that have to be met for the system to work as intended, but I’ll provide more details later.

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Paul-R
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by Paul-R » 12 Dec 2018, 10:46

As a side issue it's interesting that your 1.6HDi uses the reversible alternator and ours (in the 308) uses a heavy duty starter motor. I wonder what determines which system is fitted.

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lesliepg
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 12 Dec 2018, 11:23

GiveMeABreak wrote:
12 Dec 2018, 10:34
Can you pop up your VIN up so we can determine complete specifics fitted and I’ll get back a bit later.

I can say there are specific conditions that have to be met for the system to work as intended, but I’ll provide more details later.


Hi, Thanks for looking. Its: VF7**************[VIN obfuscated, can be read by forum staff]

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lesliepg
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 12 Dec 2018, 11:50

Paul-R wrote:
12 Dec 2018, 10:46
As a side issue it's interesting that your 1.6HDi uses the reversible alternator and ours (in the 308) uses a heavy duty starter motor. I wonder what determines which system is fitted.
alternator BAS.PNG
Reversible Alternator in DS5 e-hdi

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by RichardW » 12 Dec 2018, 13:27

I agree that it sounds like the belt is slipping when the alt tries to restart the engine. If you can get someone else to sit in the driver's seat you should be able to confirm this visually - just make sure it doesn't run you over!!

Here's the diagram for the alt belt. Interesting that there are 2 tensioners. I would replace the belt first, and see where that gets you; only moving to the tensioners if it's still slipping.
ds5altbelt.JPG
Oddly they are completely different prices!

Description Quantity Price excl. VAT Price incl. VAT Total incl. VAT Selection
1611426580 DYNAMIC TENSION 1 76.88 GBP 92.26 GBP 92.26 GBP

1631481580 DYNAMIC TENSION 1 30.2 GBP 36.24 GBP 36.24 GBP

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Paul-R
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by Paul-R » 12 Dec 2018, 14:19

Thanks for the screenshot Leslie but it doesn't explain why that method was chosen over the HD starter motor. Anyway, back to the topic.

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lesliepg
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 12 Dec 2018, 14:21

I was going to take a chance and buy the Official Citroen Tensioner Kit includes Belt and the 2 tensioners which I can get for £100.

Then with the advice given try the belt first then failing that replace the tensioners. I have noticed that the arm tensioner seems to be a bit noisey and jumps quite a bit. I guessing tensioners shouldn't jump so much or else the belt would not have the tension it needs.

I'm also guessing the alternator is OK as its charging and no error lights or messages for under voltage. Those reversible alternators are bloody expensive!!!

Slightly off topic, Can the Start/Stop system be fully disabled via Lexia?

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lesliepg
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 12 Dec 2018, 16:21

Spoke around, Ordered the Tensioner kit. Get that tomorrow and then I'll fit it and let you guys know the outcome.

I am confident that it's the top tensioner thats at fault, noisey and quite a bit of movement. Best case is I'm replacing items that could leave me most worse off than just failing start/stop if the belt or tensioners fail fully.

Really can't think what else would squeal on attempted restart. The reversible alternator spins up at restart first, So if that slips that would explain the squeal, once the engine is running the alternator wont be pulling the belt it should then be being turned by the crank. Gotta love those starter alternators!!

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by xantia_v6 » 12 Dec 2018, 17:32

If the belt has been slipping for a while, it could have also worn the grooves on the pulley which will reduce the grip of a new belt.
Does this setup also have a clutch in the alternator pulley? if so, that would also be a suspect.

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by RichardW » 13 Dec 2018, 08:38

I had a thought about this....

In the normal course of running the power comes from the crank pulley, and pulls the belt round the alt and the AC compressor, the the top tensioner is on the 'dead' side of the belt, and there will be a tendency to extend the bottom tensioner which is on the 'live' side of the belt. When the S/S tries to re-start the engine, the situation is reversed, and the belt between the crank and alt becomes the 'live' side as the alt is doing the pulling, and it will tend to try and straighten out the top tensioner, whilst the bottom one relaxes a bit. So, if the top tensioner has gone slack, then the alt is probably pulling it right to the end of its free play, and there is not enough take up in the bottom tensioner to keep the belt taut, and it slips (probably on the crank pulley). Perhaps this continuous reversal of stresses wears out the tensioners faster than normal - another downside to S/S after the requirement to use AGM batteries that cost twice as much as std ones,and only last half as long! I can't believe the S/S will ever save enough fuel to cover the cost of the battery, let alone new tensioners....

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by GiveMeABreak » 13 Dec 2018, 11:28

A diagnostic with Diagbox will help identify the fault as even an alternator belt slip will provide a P1382 fault "Reversible alternator belt: Excessive slip" or even a P1383: "Detection of imminent breaking of the reversible alternator belt" So I think it would be worth checking the faults first.

General information concerning the ECO display lamp status:
Information sent to the driverStatus of the function
- Lighting of the "ECO" warning lamp in the instrument panel
- Rev counter needle at 0 rpm
Authorisation of automatic stopping of the engine
- 3 successive flashes of the "ECO" warning lampProhibition of automatic stopping of the engine for system requirements
- Extinction of the "ECO" warning lampRestarting of the engine following a request from the driver
- 3 successive flashes of the "ECO" warning lampAutomatic restarting of the engine for system requirements
Faults:
Information on the appearance of a fault on the Stop and Start function:
  • Flashing of the Stop and Start function switch activation/deactivation/fault warning lamp for 7 seconds
  • Display of the message "ECO deactivated" on the instrument panel matrix
If the Stop and Start function has a fault, a press on the activation/deactivation switch for the function will make the warning lamp flash for 7 seconds.
N.B.: The Stop and Start function switch activation/deactivation/fault warning lamp remains lit after flashing.

Information on the disappearance of a fault on the Stop and Start function:
  • Extinction of the warning lamp on the Stop and Start function activation/deactivation switch
  • Display of the message "ECO activated" on the instrument panel matrix

User conditions authorising automatic restarting of the engine:
  • Brake pedal released and engagement of a gear on piloted manual gearbox
  • Clutch pedal pressed on manual gearbox
  • Deactivation of the Stop and Start system by the driver
  • Demisting/de-icing
  • Cabin temperature not corresponding to the request from the driver
  • Air conditioning request
  • Application of the electric parking brake
Conditions prohibiting restarting of the engine:
  • Traction chain closed
  • Power accumulator charge status inadequate
  • Low battery charge status

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by lesliepg » 14 Dec 2018, 09:24

UPDATE
I have installed 2 new belt tensioners and belt. And... I may have found the cause of my issues! :shock:
tensioner.jpg
As you can see from the photo it looks as if the secondary sprung roller has blown up at some point, This would explain the lack of full tension on the belt thus making the upper tensioner bounce and lose purchase on the belt when the stop/start system tried to turn over the engine.

After a test drive, ALL IS WELL!! If not better, As you can imagine not having full tension on the belt would have affected the efficiency of the AC, alternator and battery.

Thanks all for you help and advice. =D>

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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by GiveMeABreak » 14 Dec 2018, 16:04

Well done and will be useful for others in future experiencing the same issue.

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white exec
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Re: Start/Stop Issue Advise needed, Belt Tension?

Post by white exec » 14 Dec 2018, 17:13

Good work in tracking that down. As described above, these tensioners will have a hard life as they have to cope with both normal and cranking belt directions/tensions.