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Old 12th October 2023, 12:17   #106
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

It could be micro-hybrid system that shuts of engine briefly. And the brakes lose vacuum.

I have experienced it in S-cross too. At crawling speeds around 5 km. It creates very difficult situation for the the driver. My friend (owner of the car) actually rear-ended few times. Thank God that the speeds are always slow. And he is an very experienced driver.

Simple jugaad is to shut off micro hybrid system. The real problem is the way Suzuki has implemented the system. It always switches on the micro-hybrid after starting the vehicle. And you have to manually shut it off every time.

It is easy to forget to shut it off after brief stops. Even if they have to offer this system, the user should be allowed to shut it off completely.

I wonder why Suzuki chose to put this unwanted consumer-grade toyish/useless feature in a vehicle like Jimny which can be used in diverse terrains.

I drove Gypsy in 1.5 decades. I wish modern day engineers understand what their predecessors had achieved decades back. Rock solid performance. Indian army approved that vehicle.

Putting useless features in such a machine is silly. This is the main reason I did not upgrade to the current version of Gypsy.
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Old 17th October 2023, 06:49   #107
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

If enuine switches off, driver would instantly notice the dropping rpm. Also ac would get switched off. But waiting for high altitude users to opine.
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Old 17th October 2023, 10:31   #108
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

Quote:
Originally Posted by wanderhermit View Post
I wonder why Suzuki chose to put this unwanted consumer-grade toyish/useless feature in a vehicle like Jimny which can be used in diverse terrains.
To achieve a better ARAI fuel efficiency figure and lower average real time driving emissions.

Quote:
Originally Posted by wanderhermit View Post
I drove Gypsy in 1.5 decades. I wish modern day engineers understand what their predecessors had achieved decades back.
The "modern day engineers" are now keyboard warriors. PPT, Excel, CatiaV5/V6, Hypermesh, Nastran, GT power etc.
The fun begins when you ask them to correlate the computer derived values with the values achieved from prototype testing. Even more fun when you ask these "digital dragons" to build a physical prototype. They literally run around like headless chickens.

Intelligent automobile talent is as rare as hen's teeth in the automotive kingdom of India. Some are there - mainly TML and M&M. Rest are all on an AMT & a prayer!

Putting useless features in such a machine is silly. This is the main reason I did not upgrade to the current version of Gypsy.
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Old 23rd October 2023, 21:47   #109
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

Quote:
Originally Posted by arjab View Post
To achieve a better ARAI fuel efficiency figure and lower average real time driving emissions.
Just for reference that start stop system has saved me a staggering 9 Litres of oil over 17k ownership of owning a K15C powered car.
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Old 30th October 2023, 18:00   #110
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

An update to this thread:

I got an email from Maruti Suzuki Territory Service Manager – Nexa as follows
Quote:
Dear Sir,

Greetings from Maruti Suzuki !!!

We hope that this communication finds you in good health.

From the communication shared, there are 2 problems reported by yourself specifically at High Altitude driving AT vehicle, [A] Brake Pedal Hard and [b] Transmission Shifting from 2H to 4H.

To overcome both conditions, vehicle has to increase the Engine RPM as advised in the manual as well. Sample of the manual is also attached for your reference.

Assuring you of Best Services always

Regards


The email had the pdf attached which is uploaded here as an attachment.

As we all had already discussed, it seems that Suzuki already knew this issue and have crafted the user manual by suggesting "ways" to drive on hills; but by sharing this, they have acknowledged the presence of the issue.

Quote:
To overcome both conditions, vehicle has to increase the Engine RPM
What if the driving situation does not allow one to rev?

Scenario - Lets say I am climbing a steep slope and Jimny is struggling to climb even in 1st gear in AT (at 1300-1400 RPMs) and suddenly I see a truck coming downhill on slope. How can I rev with the Jimny in this case (how to stop back rolling) ?


The primary intent of this post was to get corrective action from Maruti Suzuki and the secondary intent was to make everyone aware of this issue.

I guess this thread can now remain dormant unless I or someone else gets any more updates.
Attached Files
File Type: pdf Advice for Driving on Hills.pdf (1,004.6 KB, 95 views)

Last edited by purohitanuj : 30th October 2023 at 18:12.
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Old 30th October 2023, 18:13   #111
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

Quote:
Originally Posted by purohitanuj View Post
As we all had already discussed, it seems that Suzuki already knew this issue and have crafted the user manual by suggesting "ways" to drive on hills; but by sharing this, they have acknowledged the presence of the issue.
The 1st page in the PDF is very vague. Are they saying that the brake pedal will become hard because the driver is not keeping the engine in high revs? How is one supposed to be in D-Drive while coming down and expect to rev the engine high to keep the brake pedal.

I feel that PDF and the reply from Maruti is asking for a safety related trouble down the hill, err, down the line.
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Old 1st November 2023, 19:16   #112
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

Very sad to see Maruti ignoring such an issue of great gravity with such callousness. There could be many scenarios where the AT car cannot be revved. The basic instinct of braking while driving should always combine with the thought of revving the engine to have a good braking effectiveness is too much an ask. Hope Maruti address this issue promptly with some update. Cannot think this is an impossible ask for Maruti to correct and even more, cannot think Maruti released this car with the knowledge of this issue.
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Old 5th November 2023, 10:22   #113
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

This post by Suvolens (Delhi - Srinagar - Leh - Hanle - Umling La - Manali in a Maruti Jimny) also highlights this braking issue above 17000/18000 feet range.

Maruti really needs to take this seriously and get it fixed. This is playing with the lives of people.

Shame on Maruti for giving such a casual response to a customer who trusted the brand for best engineering.

I had decided to buy Alpha AT in another 3-5 months after lot of looking as I need SUV for remote Himalayan travels which are fairly significant in number.

Now, it seems I will need to relook at Thar 5 door which I had decided to drop due to DPF issues reports, or even a 2WD SUV.

Last edited by RDS : 5th November 2023 at 10:38.
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Old 14th January 2024, 10:26   #114
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

I was discussing this in the Jimny group the other day, worth bumping up this thread. More than a few owners are facing issue with spongy and dead feeling brakes at normal altitudes. All the cars are now decently used with >5000km milage. The usual suspects were checked, brakes bled. Brake fluid changed and inspected the rear drums as-well. But the spongyness doesn't go away. Likely a failed or non-performing brake booster unit. Will keep this thread updated with our findings.
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Old 14th January 2024, 11:04   #115
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

I have had the experience of the brake booster not working as expected once in the last 6 months. The feel was similar to what I had experienced in my 2011 Swift Petrol - the brake pedal momentarily went hard but recovered when engine RPM went up - and it happened in the same circumstances that is the engine was near idle and at low speed. The problem is due to the little vaccum these engines produce because of egr (internal) which doesnt let the manifold to be in vacuum even with throttle closed; besdes emissions its done to improve fuel efficiency during coasting/crusing when the engine load is low.

The loss of vacuum can be mitigated by using a large vacuum reservoir with a check valve in the line tha goes to the brake reservoir. Almost all diesel SUMPVs have an external inline vacuum reservoir on the line that goes to the brake servo and if need be it would be pretty easy to adapt one from a toyota/mahindra/tata in the jimny. Manufacturer level revision could be another brake booster with a larger internal capacity. But i don't see it coming, as it was the case with Swift. In the jimny there is a vacuum reservoir behind the front fender but I think it is only for the vacuum line going to the front hubs.
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Old 21st February 2024, 09:27   #116
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Re: Maruti Jimny AT | Brakes not functioning at low rpm at high altitudes

Yes, there could be many ways to stop loss of vacuum.

1. As explained above by Shankar
2. Having an electric booster just like full time ev/hybrids
3. Or by allowing the driver to choose the default mode of micro-hybrid turned off.

I think the third option just requires software alteration. Without any extra hardware changes.

For example, if I am driving to ladakh, I should be able to turn off this hybrid system till the time I am in mountains. Saving few litres of oil may not matter compared to the safety of the occupants. How hard is it to let the driver decide what he wants to do with his own vehicle? Especially when it comes to basic safety issue like braking. And this solution just requires an extra software menu. Nothing else!

Compared to the current suggestion in user manual to rev the engine when you actually want to apply brakes! Common sense guys!

Best would be to have small hardware button with an Led. Just like a simple toggle. Micro- hybrid on/ mircro hybrid off.

Last edited by wanderhermit : 21st February 2024 at 09:35.
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