[stanjohn123]

So here is the update. The mechanics tried to change the switch under the brake pedal, but this was still of no use as the problem came back again. So now they have decided to replace the Fuel Pump and Tank. Waiting for parts to arrive this week. Will update once done and I test drive for a while.

We will surely get a solution from TATA.

[audioholic]

I am unsure how changing fuel pump and tank is going to help in your case. It is an issue with the software. Regarding brake switch, the moment the brake is disengaged, the signal is sent to the AMT module to begin creep. After this, its all the software that is in play which decides how your car should move forward and the throttle input from driver is given priority only after the initial creep begins. Adjusting the brake switch is a jugaad method to enable quicker creeping because that will make the switch signal to AMT before the brake pedal is completely released. This might also cause issues when there is a light foot on the brake and the car tries to creep.

Typically, issue with delay in creeping or lag is addressed automatically by the AMT unit since it learns the bite point of the clutch and keeps the clutch slightly before this position when the brake is applied. Hence, the creep will begin immediately once the brake is released.

I hardly use the handbrake in my car to launch up an incline. After a good round of training the AMT, this is not needed since I have instantaneous creeping in my car and a slight shove on the A-Pedal is enough to get the car going ahead without any roll back.

[Nanolover]

Update Again :

The entire fuel tank., pump and delivery system/ wiring harness concerned have been replaced under warranty.

I have driven it for 200 + kms after that and now the problem is solved.( although jerking during on/off throttle application - aggressive fuel cut off switch/ 3 cylinder engine being the culprit is there)

No more stuttering/lag and panic moments in inclines.

The obvious sign you can notice is more fuel pump priming noise when you turn on the ignition.( the original sound was asthmatic in comparison)

Tata Senior management to whom I had escalated were very proactive and ensured swift action to get the problem solved.

I feel it is a defect for a particular batch of 2018 fuel systems supplied .

[stanjohn123]

Originally Posted by Nanolover

Update Again :

Tata Senior management to whom I had escalated were very proactive and ensured swift action to get the problem solved.

I feel it is a defect for a particular batch of 2018 fuel systems supplied .

Hi, did you test drive with AC ON ? Has the fuel mileage improved too ?

Yes it seems only few batches of 2018 were affected. I will be sending my car in tomorrow for the replacements.

[Dr.Suraj]

Originally Posted by Nanolover

Update Again :
The obvious sign you can notice is more fuel pump priming noise when you turn on the ignition.( the original sound was asthmatic in comparison)

Tata Senior management to whom I had escalated were very proactive and ensured swift action to get the problem solved.

I feel it is a defect for a particular batch of 2018 fuel systems supplied .

That's an exhaustive list! Sorry to know this arose, but also heartened to know it got resolved well. That pump 'priming' sound symptom is something I will keep a sharp ear for going forward.

[rahul2092]

Originally Posted by stanjohn123

Hi, did you test drive with AC ON ? Has the fuel mileage improved too ?

Yes it seems only few batches of 2018 were affected. I will be sending my car in tomorrow for the replacements.

Which service center in Bangalore you did part replacement? I have Tiago (july 2018 make) having same issue and failed to convince service center guys. They always said all AMTs are like this only, and I failed to convince them.

[Nanolover]

Hi. It was done in trivandrum motors, Trivandrum. I am based in trivandrum. (Sorry forgot to update location!).

Contact rahul- customer service head there.

No service center will proactively replace parts under warranty unless they are forced to.it involves a lot of paperwork and money which no one sadly is bothered to do.

@staan -yes all driving was with ac on.-but the confusion of changing gears when going up a steep slope is there in normal mode (typical of all amt )but it quickly changes to a lower gear and manages well.

[stanjohn123]

Originally Posted by rahul2092

Which service center in Bangalore you did part replacement? I have Tiago (july 2018 make) having same issue and failed to convince service center guys. They always said all AMTs are like this only, and I failed to convince them.

I’m getting mine done from Nagercoil. Make sure you are facing the exact same problem like us. Inconsistent throttle response and difficulty or lag while climbing a hill.

The usual consistent lag in AMT gearbox is normal.

[sagarpadaki]

Originally Posted by Nanolover

Update Again :

The entire fuel tank., pump and delivery system/ wiring harness concerned have been replaced under warranty.

I have driven it for 200 + kms after that and now the problem is solved.( although jerking during on/off throttle application - aggressive fuel cut off switch/ 3 cylinder engine being the culprit is there)

No more stuttering/lag and panic moments in inclines.

The obvious sign you can notice is more fuel pump priming noise when you turn on the ignition.( the original sound was asthmatic in comparison)

Tata Senior management to whom I had escalated were very proactive and ensured swift action to get the problem solved.

I feel it is a defect for a particular batch of 2018 fuel systems supplied.

Which month is your car manufactured?

Also, this priming noise that you mentioned, is it the same noise that comes on when the driver door is opened?

[Nanolover]

Month of manufacture - july 2018

The noise is the fuel pump priming noise when you switch on the ignition ( from around the fuel tank area as in any electronic fuel pump car) -not the AMT priming noise when you open the driver door

Open the door- amt pump activation sound - close door -

switch on ignition- fuel pump priming sound -then start car

hope this is clear

[stanjohn123]

To help customer's differentiate between typical AMT gearbox characteristic and the problem actually faced by few of us, I'll state both of them in points below.

Typical AMT Shortcomings
-----------------------------

1) Slow Gearshifts.
2) Slight Rollback while starting from an Incline.
3) Gearbox confusion while climbing a hill.
4) Slight Jerkiness in On/Off throttle application.

Problem's we faced
----------------------

1) Sudden loss of power while travelling up a hill, this will surprise you as the car will roll back suddenly.
2) Loss of power while moving forward from dead stop.
3) Random surge of power while moving moving forward or taking reverse.
4) Inconsistent Throttle response.

As you all know, the problem was solved and the culprit was not the AMT gearbox but the Fuel Pump, Fuel Tank and Wiring harness.

You can further check out my driving experience after the fix in the video below.

https://www.youtube.com/watch?v=tK8u1ExSl3I&t=1s

[rahul2092]

I have been following up this issue in Bangalore(kropex auto) for 2 weeks for my Tiago XZA. Multiple folks from Bosh/Tata inspected the vehicle and acknowledge the problem. Now I am getting a word from Tata that this issue will be fixed by a software update. ie. No longer replacing any fuel system parts as per Tata. I will be getting a software update in a weeks time. Not sure whether this alone fix the issue..

[giri1.8]

Originally Posted by Nanolover

Request GTO and other moderators to highlight this issue


It has a flat spot just off idle.

It will not respond at signals, when stationary, on inclines, etc. The 2 to 3 seconds lag is there. It's like the engine hesitates, is starved of petrol and then there is the misfiring/blowing sound like a small cracker has gone off and then if we give more throttle the car just shoots forward.

Sequence of events at a signal or when you join from a byroad to main road (maybe Stan can concur):

1. Signal turns green.
2. Press throttle ... brr brr brr hesitation, no response - people behind start honking.
3. Sometimes a misfire/blow back popping sound like someone farting happens (old Bullet, 2 stroke rickshaw pop sound).
4. Then the car finally picks up.

Has this issue been resolved? Mine has this problem rarely, but it is embarrassing when it happens, was unable to recreate it at the time of service, hence nothing has been done.

[Sai Narayan]

Originally Posted by Nanolover

Update Again :
I feel it is a defect for a particular batch of 2018 fuel systems supplied .

It's not with just 2018, I've got a 2017 December model which also has the same problem and I've had multiple discussions with the team which has been turned down for any replacement w.r.t Fuel Pump which I've brought their attention to multiple times. This time am not taking "No" for an answer and am planning to get to the bottom of the issue. Will keep you all posted.

Here is the Link where-in I've been discussing on this for quite sometime.

https://www.team-bhp.com/forum/techn...nt-petrol.html (Tata Tiago chokes for want of petrol)

[super.veloce]

Hello everyone, I am a newbie to the forum so kindly excuse me if I am repeating any of the points already cleared in the above sections. We have booked a Tata Tiago xza+ last week and I wanted a clarification regarding the issue pointed out in this thread. Has this problem been rectified in the 2019 variants as opposed to the 2018 variants?

TIA for the response.