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Old 28th January 2011, 13:05   #1
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Question Braking problem in Indica vista (safire) with A/C ON

Hi Everyone,

I own a Indica vista (safire). Its a petrol version.
I want to first know whether there is any fellow member who owns the same varient as me?

I'm experiencing this since I got the car. Here is the problem :
Whenever i'm driving with the ac ON and i'm in 2nd gear and approach a signal and come to crawling speeds, the brake pedal becomes really hard and car keeps crawling and doesn't slow down!! Really hard as if there is no power assist!!
I usually brake first and apply clutch just before the car comes to halt, but this car keeps crawling at same rpm and speed. The only way to avoid this is to clutch it simultaneously with brake which I hate doing. This is not found when the ac is OFF, I'm able to brake and slow down the normal way and apply clutch to avoid stalling.

This can be dangerous as someone unfamiliar with my car can bump into the car at front!!!

I had posted this on other forum before I became a member of team-bhp. I was asked to explain the showroom guys whats happening more precisely.

Today I've given my car for 20000k free service and when I discussed this with my service advise, this is what he had to say : "Most of the vista safire owners have complained about this and we have no clue about what has to be done, you have to live with it!! It is a problem with the design of braking system."

I was shocked hearing this. Is there ant way to reach the company to fix this problem?

Thanks,
cosmos
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Old 28th January 2011, 15:42   #2
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Default Re: Braking problem in Indica vista (safire) with A/C ON

It seems that with AC ON, the engine is not developing enough power (or revving high enough) to adequately pressurize the hydraulic lines.

As a start, try bleeding the lines for air.
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Old 28th January 2011, 16:00   #3
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by dhanushs View Post
It seems that with AC ON, the engine is not developing enough power (or revving high enough) to adequately pressurize the hydraulic lines.

As a start, try bleeding the lines for air.
Agree. It seems that there is not enough assist by the brakes when the airco is on. I have driven a friends Vista,(Diesel) and did not have any breaking issues with it.

Does this happen only in 2nd gear and at crawling speeds?
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Old 28th January 2011, 16:02   #4
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Default Re: Braking problem in Indica vista (safire) with A/C ON

I have not driven the Vista Petrol, so take this with a pinch of salt.

When AC is switched on, the RPM is usually increases to allow for more power for the AC. What this means is that, the normal idle RPM would now be close to 1000 rpm, from the earlier 700 to 800 rpm.

What does this have to do with your problem?
When you get close to a signal, and apply brakes, IF THE RPM goes below the idle RPM, the car will stall. To prevent stalling the ECU tries to keep up the RPM, and this might have made you to feel that the engine is pushing the car at the same time the brake is being applied.

I dont think there is any solution here, but i suggest that the correct practice should be to apply slight brake when slowing and downshift at the same time. The downshift also allows for some engine braking, and makes sure that the car does not stall (or anywhere even close).
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Old 28th January 2011, 16:37   #5
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by kaushikr View Post
Agree. It seems that there is not enough assist by the brakes when the airco is on. I have driven a friends Vista,(Diesel) and did not have any breaking issues with it.

Does this happen only in 2nd gear and at crawling speeds?
kaushikr,

Yes, the showroom guys told me that this is the case only with the petrol varient.
Yes, the problem can be sensed when I slow down from 2nd gear and sometimes in the 3rd if i'm lugging the engine.
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Old 28th January 2011, 16:42   #6
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by deep_bang View Post
I have not driven the Vista Petrol, so take this with a pinch of salt.

I dont think there is any solution here, but i suggest that the correct practice should be to apply slight brake when slowing and downshift at the same time. The downshift also allows for some engine braking, and makes sure that the car does not stall (or anywhere even close).
deep_bang,

From 2nd gear I don't think one needs to downshift to stop. I've driven a lot of cars (petrol and diesels as well) and my way of slowing down and stopping is the same in every vehicle. I understand that you're telling me the way to live with it but when other vehicles don't give any problem, I think this should be fixed.

Also, the concorde motors(mysore road Banglore) are present to the problem from lot of owners but they're not doing enough to rectify!
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Old 28th January 2011, 17:20   #7
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by cosmos View Post
Hi Everyone,

I own a Indica vista (safire). Its a petrol version.
I want to first know whether there is any fellow member who owns the same varient as me?

I'm experiencing this since I got the car. Here is the problem :
Whenever i'm driving with the ac ON and i'm in 2nd gear and approach a signal and come to crawling speeds, the brake pedal becomes really hard and car keeps crawling and doesn't slow down!! Really hard as if there is no power assist!!
Perfect!

I do own a Vista Safire Aura and I have always faced this exact issue. With A/C ON and in the 2nd gear, it feels impossible to brake in urgent situations.

I spoke to the SAs in Pune and I got the same answer. This issue seems to be similar to the rattling steering issue in i20s. Both companies have not been able to find any solution.

So what do you do in such urgent situations? I have got so used to this terrible problem that whenever I am approaching a very heavy traffic jam, a signal or anything similar, I switch off the A/C. Just live with it.
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Old 28th January 2011, 17:30   #8
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Default Re: Braking problem in Indica vista (safire) with A/C ON

apparently you are not the only one facing this issue.
a simple google search threw up over 260,000 hits for this issue.

TATAMOTORS/Indica Vista Sapphire Complaints - Braking problem in Indica Vista Sapphire when Air Conditioned is ON

many people have also complained on consumer forums and the answer from tata to all these people is the same. Live with It.

I would suggest the following

1. bleed the brakes. (authorized service center of-course)
2. when applying brakes in slow moving traffic or when coming to a halt, depress the clutch completely and then apply the brakes and update if this still persists.

Last edited by Godfather : 28th January 2011 at 17:31.
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Old 28th January 2011, 18:37   #9
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by ajay_satpute View Post
Perfect!

So what do you do in such urgent situations? I have got so used to this terrible problem that whenever I am approaching a very heavy traffic jam, a signal or anything similar, I switch off the A/C. Just live with it.
Hi Ajay,

I usually depress the clutch COMPLETELY be it at any speed and brake. Sometimes it works but other wise I follow the same what you've been doing!! Turn AC OFF much before I approach the signal or slow moving traffic

So what shall we do now??
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Old 28th January 2011, 18:41   #10
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by Godfather View Post
apparently you are not the only one facing this issue.
a simple google search threw up over 260,000 hits for this issue.

1. bleed the brakes. (authorized service center of-course)
2. when applying brakes in slow moving traffic or when coming to a halt, depress the clutch completely and then apply the brakes and update if this still persists.
godfather,

1. I'll inquire about this in the service center.
2. Yeah, this is exactly what I do. Depress clutch much before I brake. This is the only way out. But in case you're at really low speed, this too does NOT work!! So most of the times I travel without AC! Now the summer is approaching and I'm breaking my head over this.

Thank you sir.
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Old 28th January 2011, 18:43   #11
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Default Re: Braking problem in Indica vista (safire) with A/C ON

[quote=ajay_satpute;2224626]Perfect!

I do own a Vista Safire Aura

BTW, Ajay I own same model, same variant and same color as your car
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Old 28th January 2011, 19:21   #12
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Default Re: Braking problem in Indica vista (safire) with A/C ON

So, this is indeed an issue faced by many.

I strongly suspect, that ECU isnt sensing the loss in hydraulic pressure in brake lines, and it is NOT compensating for the loss by increasing the idling.

Quote:
Originally Posted by ajay_satpute View Post
So what do you do in such urgent situations?
Why don't you downshift so that the engine rpm increases, and moreover, you can make use of the engine braking too.

Also, next time when this happens, just try revving the engine and see if the brakes work fine (Be Cautious, Saftey 1st!). If so, its definitely a bug in the ECU, and can be rectified by only by an updated firmware from TATA.

On the brighter side, Vista Safire users may be forced to drive aggressively (and safely). Keep the engine on boil at all times. So that they can brake better.
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Old 28th January 2011, 19:32   #13
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by dhanushs View Post
So, this is indeed an issue faced by many.

I strongly suspect, that ECU isnt sensing the loss in hydraulic pressure in brake lines, and it is NOT compensating for the loss by increasing the idling.
Hey dhanushs,

If its a bug in the ECU, how can we bring it to the notice of the people in TATA MOTORS who are concerned with developing the firmware?
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Old 28th January 2011, 19:35   #14
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Default Re: Braking problem in Indica vista (safire) with A/C ON

I fail to understand how such an issue has got so little exposure on this forum. This thread is yet to go into second page !!!

What is Tata doing?? Just shrugging the shoulders???
Depressing the clutch totally before applying brake is not a recommended way. Will lead to premature brake pad wear. Also engine braking gives a smaller braking distance.

Last edited by download2live : 28th January 2011 at 19:37.
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Old 28th January 2011, 19:41   #15
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Default Re: Braking problem in Indica vista (safire) with A/C ON

Quote:
Originally Posted by dhanushs View Post
So, this is indeed an issue faced by many.

I strongly suspect, that ECU isnt sensing the loss in hydraulic pressure in brake lines, and it is NOT compensating for the loss by increasing the idling.



Why don't you downshift so that the engine rpm increases, and moreover, you can make use of the engine braking too.

Also, next time when this happens, just try revving the engine and see if the brakes work fine (Be Cautious, Saftey 1st!). If so, its definitely a bug in the ECU, and can be rectified by only by an updated firmware from TATA.

On the brighter side, Vista Safire users may be forced to drive aggressively (and safely). Keep the engine on boil at all times. So that they can brake better.
An Ecu has got nothing to do with Hydraulics in the Brake lines. There is no provision to sense this.

Secondly I fail to understand what does AC have to do with 'braking' ? Even when the AC is running, it is sucking out engine power from the pully to the AC compressor and there is no vaccume pressure from the Engine required for the AC.

Even like someone said if the idling RPM is not going up by 100 or so rpms when the AC is switched on, that should not be a problem as the brake booster would be anyway fill itself with vaccume when the AC is not switched on and the RPM is same.

All I am trying to say is that AC and Braking have no connection at all as nothing is connected.
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