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Old 1st March 2011, 00:00   #31
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Default Re: Braking problem in Indica vista (safire) with A/C ON

This problem exists with my car as well. It happens in 2nd gear mostly.
My workaround to this is to use the clutch while slowing down, where I can downshift to 1st and then brake.

The car, pulls in 2nd gear, even if the AC is off. Most of the times I have to use the clutch. Thats why normally I dont let others drive the car.*Good reason!
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Old 1st March 2011, 11:08   #32
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Default Re: Braking problem in Indica vista (safire) with A/C ON

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Originally Posted by cosmos View Post
Hi Sutripta,

I'm confirming. When you slow down by taking your foot off throttle, the engine rpm refuses to reduce. It stays where it is! The car keeps pulling without throttle or clutch being pressed and brake pedal is very very hard.

But if engine rpm is above 2k, the brake is normal and I'm able to stop. Re-iterating, the problem persists only at low speed and rpm.
cosmos, the above phenomenon, i.e. the engine rpm staying constant without foot on the throttle pedal, would be seen in all cars being controlled electronically. The brake pedal being hard is definitely a problem and seems specific to Indica Vista (P).

(1) Could you be a little more specific on what is low speed and low rpm.
(2) What are the low rpm's (when you face the issue with brake hardening) in 2nd gear with and without the A/C. (Please drive carefully when trying to find this information.)
(3) What is the usual idling rpm.


Quote:
Originally Posted by cosmos View Post
Hi Guys,

We have discussed about the problem. Some of you have given solutions. Can somebody sum up the feasible solutions for me? Someone told about bleeding brakes, re-mapping ecu and even getting a new ecu. How many of these are feasible?

Car is only 13 months old. Warranty would be an issue in case I do something.

I can think of two ways:

1. Get in touch with someone higher up in TATA and ask them to find a solution.
2. Get it done myself from some other service station who know what they're doing(forget warranty).

Which do you think is a better way to go?
The issue is a bit perplexing as, it could be a case of insufficient vacuum assist at higher rpm's with A/C (the brake hardening points towards reduced assist), but this is unlikely IMHO because If there is insufficient brake assist at lets say 1200 rpm, the situation should get worse at 1500 rpm when the engine is using more of intake air up.

One thing you can do is to confirm if the diesel Vistas have Vacuum pumps (they should, but better confirm it out of a service personnels mouth). This will then point towards an issue towards the Vacuum booster in the petrol versions as the diesels don't suffer from similar brake performance issue.

Getting a new ECU will not help your case as the same issue exists in all Vista (P) cars. The way forward is to write to the Tata higher ups. The more emails/complaints they get, the sooner they should act.

All the best and keep us posted.
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Old 8th March 2011, 05:12   #33
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Default Re: Braking problem in Indica vista (safire) with A/C ON

[quote=kaushikr;2261418]

(1) Could you be a little more specific on what is low speed and low rpm.
(2) What are the low rpm's (when you face the issue with brake hardening) in 2nd gear with and without the A/C. (Please drive carefully when trying to find this information.)
(3) What is the usual idling rpm.

Kaushikr, I'm on a business trip at Sunny Vale CA now. Will get back to you precisely once I reach back.

From what I recollect,
1. Speed below 25kmph.
2. rpm below 1.5k to 1.8k in 2nd or t3rd gear.
3. usual idle is 900rpm.
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Old 20th October 2011, 17:04   #34
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Default Re: Braking problem in Indica vista (safire) with A/C ON

An update on this issue. I recently discussed this with a senior manager at FIAT drivetrain. He said that the ECU is mapped to not stall at low RPM's which are typically encountered at speeds less than 10kmph in second gear.

He also said that you could just depress the clutch while braking. The torque on the clutch pad is not enough to damage it at these speeds. Also due to the low speed the brake pads will not wear out faster.

This feature on the ECU is also helpful when climbing inclines where the car does not stall.
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