My 2019 Harrier is shaking & bouncing at idle: What could be the cause

Please don't confuse this with "vibrations at idle". When I say shake - I mean the car literally bounces at idle.

BHPian pkulkarni.2106 recently shared this with other enthusiasts.

Greetings experts!

I've recently purchased a pre-owned Tata Harrier XT (Dec 2019). The car runs fine for the most part - no niggles as such.

But there's very intermittent issue that I face - very very randomly (like once in a month or so) the car shakes at idle. Please don't confuse this with "vibrations at idle". When I say shake - I mean the car literally bounces at idle. Let me try to describe the shake - it's like you're driving on rumbler strips at very low speeds OR you're standing still & someone is jumping in the car.

When this happens, the car shakes around 4-5 times a second. It's been around 4 months since I purchased this car & I've seen this issue 5-6 times till now. Till now the issue has only occurred during deceleration & coming to a halt (traffic signal or an intersection on the road). No CEL on the dashboard at this point. Also, whenever this occurs, a gentle dab on the A-pedal makes the shaking go away.

When I search for "engine shake" online or on the forum, mostly the "vibration" results show up & the usual suspect is clogged injector(s). To rule it out, I tried Liqui-Moly Super Diesel Additive last month, after which the intensity of the shaking has reduced a little bit. But it's still there.

Since this issue has only happened on intersections/traffic signals, I didn't get a chance to open up the bonnet & look at the engine. I tried my best to replicate the problem in my parking lot, but I could never do so.

Can the experts here shed some light on what could be this cause?

Thanks!

Here's what BHPian mayankk had to say on the matter:

Apart from the injectors, do get your mounts checked as well. That much shock from the engine should not get transferred. Why I thought about the mounts is if the jolt from the engine was large enough to cause the car to bounce, it would have to something catastrophic with the engine, which, as you mentioned, it is not.

Here's what BHPian vinay.sathyan had to say on the matter:

This is based on my personal experience. Back when i had my Verna, i faced a similar problem. I start the car and immediately the vibration was clearly observed.

Upon inspection, found that there was a rat bite and it had bit the ECU wires going into the Engine. Just one of the wires.

It appears this led to some timing issues in the engine and most likely the pistons we off sync and this led to the vibration.

After getting the wiring fixed and ECU reset, things were back to normal.

One more point, the Engine/ECU warning light did glow for me when i faced this problem.

This might not be the exact problem you are facing, but food for thought.

Here's what BHPian DicKy had to say on the matter:

Natural Harrier problems, especially one of the 2019 first batch. Service centres will say that the idler pulley has to be tightened or replaced.

Here's what BHPian Jeroen had to say on the matter:

It appears to be an intermittent problem and one that does not occur very frequently. Which means you can more or less rule out all usual “vibration suspects” such as engine mounts, injectors etc. They would rarely cause an intermittent problem.

I would check with an engine/manufacturer specific OB d analyser to see if you have any stored codes.

I would suspect some sort of electrical fault caused by a poor connector or similar.

If there are no codes this is what I would do. Warm up the engine properly, let it idle. Then start pushing and pulling at everything. Start with the whole engine. See if the RPM changes at all if you push or pull it any specific direction. Next push and pull every electrical connection you see. Just tug gently. Observe the RPMs. Next every sensor on the car.

You might be able to find a specific component that causes the engine to shudder and or vibrate.

Good luck,

Jeroen.

Here's wht BHPian VijayAnand1 had to say on the matter:

Vibrations on a diesel are pretty common, but a judder is something sinister.

Mild judders are normal sometimes when turning on or turning off the engine.

Mild harshness depending on the condition of the engine, engine oil is pretty much normal.

Judders during normal cruising or idling, or judders coupled with rattling, tinging sounds aren't normal. Judders arise due to misfiring, worn out engine mount/beds, faulty/failing clutch assembly, especially during driving and also worn out suspension parts where they tend to make the vehicle wobble either during acceleration or deceleration when there is heavy load transfer.

Since you've iterated this issue being pronounced more at deceleration, and a gentle dab on the acc pedal causes it to behave well, it could be mechanical or electrical. It's better you try to record a video and perhaps show it to the SVC so that they get a better grasp of what's happening.

Good luck though!

Cheers!

VJ.

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