[Tamarind]

Hello Bhpians,
Mine is a 2009 Hyundai Santro, has done 1Lac Kms
Been servicing it every ~6 months and quite happy with the car
The vehicle has taken us places and been holding my trust till now

Last week when i had taken it over a 80 Km drive on Bypass, avg speed could have been 90+ and all was fine.

I exited the highway via the two 180 degree bends in the shape of "S" (probably @ 40 Km/hr) to join another highway, when i pressed the accelerator the vehicle started to stutter. (During this entire drive the road was not bumpy neither i put the car in a hard spot in high speed)

I immediately looked at the dash for engine temp, or any hazard lights - all seem to be fine. Tried Switching off the AC and accelerated the effect seems to be same

Parked the vehicle in a calm spot and took the a look under hood for any leakage to the ground - None. Checked the oil dip stick and it had sufficient level (F mark)

The engine bay though had a little wet oil spread on top of it, but that was a observation from earlier service as well and the mechanic said in next service he will apply some paste in between the layers to stop that oil seepage but nothing bad to worry about

The jerks seem to be uneven (i could not find a common time gap between two jerks). Putting the gear in neutral and accelerating does not produce any jerk


Took the car to nearest Hyundai service, they checked the following

1. Spark plugs
2. Air filter
3. Throttle body
4. Ran the computer checks for Electronics,
5. Smoke color and exhaust pipe,
6. Petrol pump, tank and filter for blockages, also
7. Suspected mix of petrol + water but later ruled out

But since they were not able to find the issue, they suggested replacing all the following one by one to test and isolate the issue

1. Spark plugs
2. Card wire
3. Ignition coil
4. Idle speed actuator
5. Fuel filter

But since they told its going to make multiple days to get all parts, and also said it can be driven (ignoring the jerks) - i decided to bring it my mechanic close to my house (with hazard lights on and driving slowly)

He inspected and changed all 4 spark plugs - instantly the jerk frequency and intensity reduced. But still not completely gone.

The mechanic says, it can be the fuel pump (which have to replaced and checked ~4k, followed by few other items costing ~24k) and then the crank shaft to be checked. Then i told him the timing belt change is due from last service (1Lac Km) for which he quotes around 6k

So total ~30k worth of parts & labor quoted,

He also says the rear left bush has worn out and the wheel gives a thud sound on minor bad roads (which is true in my observation as well) - though its not related to this problem, it needs a change for bump free ride. This might cost around 6k

The vehicle condition is good otherwise

Question:

1. What do you guys think about the above ?
2. Could the jerk be due to old timing belt ? or possible oil seepage on the belt could cause the skipping bite ?
3. Your suggestions based on prev experience, on which direction to take in addressing this issue ?
4. Possibly a time to exchange for a new vehicle ?

[MT_Hyderabad]

There is a sensor on the throttle body, check that.
Throttle body cleaning may be necessary, get it cleaned. These are the two things, which are not that costly and provides an easy fix.
I have encountered such jerks in my car, when it was 25k kms old and after many deliberations they were attributed to the loose connection of that sensor.

[Tamarind]

Originally Posted by MT_Hyderabad

There is a sensor on the throttle body, check that.
Throttle body cleaning may be necessary, get it cleaned. These are the two things, which are not that costly and provides an easy fix.
I have encountered such jerks in my car, when it was 25k kms old and after many deliberations they were attributed to the loose connection of that sensor.

Thanks for sharing your thoughts

The Hyundai service center guys said the Throttle body has been cleaned and tested but the same issue persists (will ask the mechanic to check though)

Also, if the sensor is having an issue, wont this be indicated in the computer test they performed ?

[vrprabhu]

I think the service center has given the correct route (!), which I suggest to modify this way (based on my experience of owning a car aged similar to yours ) -

1. Check and replace spark plug wires (you have already changed the plugs); check whether the accelerator pedal and cable are operating smoothly

2. Replace fuel filter

3. Replace timing belt (if not done earlier - you have a 10+ year old car with 1+ lakh on the odo and the belt would be showing signs of wear & tear plus slack)

4. Check and replace the sensors (MAF/O2) if the wires appear to be brittle / aged

5. Check Ignition coil

6. Check Fuel pump

Presume that idling is OK (i.e. not erratic) and the electricals are in good condition.

[bejoy]

Originally Posted by Tamarind

when i pressed the accelerator the vehicle started to stutter. (During this entire drive the road was not bumpy neither i put the car in a hard spot in high speed)

The same issue was observed in my dad's 2005 Santro. The engine would stutter and die after a spirited drive, with no throttle response. After switching off and cooling, the car would become normal. The issue got resolved after changing IAC (Idle Air Control) valve. The OEM part is expensive, I got the part from Aliexpress, costed less than 1k. It is 4 years now and the issue has not happened again. Worth getting it checked.

There is this thread on this issue:
(check posts by @Geo_Ipe)

https://www.team-bhp.com/forum/techn...ml#post4198880 (Santro Idle Air Control Valve)

[batish]

Originally Posted by Tamarind

when i pressed the accelerator the vehicle started to stutter.

In all these years did you get engine mounts replaced? I think they are the culprit. Usually it is made of rubber, with our temperatures and engine heat their life is not so long. It's already been 13 years, do get them checked once.

It won't be much expensive, and if you have an honest, trustworthy mechanic he'll tell you whether they need to be changed or not straightway after having a look.

[Rahul Bhalgat]

Originally Posted by Tamarind

Hello Bhpians,
Mine is a 2009 Hyundai Santro, has done 1Lac Kms
Been servicing it every ~6 months and quite happy with the car

I exited the highway via the two 180 degree bends in the shape of "S" (probably @ 40 Km/hr) to join another highway, when i pressed the accelerator the vehicle started to stutter.


Question:

1. What do you guys think about the above ?
2. Could the jerk be due to old timing belt ? or possible oil seepage on the belt could cause the skipping bite ?
3. Your suggestions based on prev experience, on which direction to take in addressing this issue ?
4. Possibly a time to exchange for a new vehicle ?

1. Try injector cleaners like Addon P. You might be aware that these are to be put in the fuel tank in a certain proportion. Consume two tankfulls. Clogged injectors may cause uneven stuttering. This will hardly cost anything and won't be a wastage anyway.
2. If new sparkplugs reduced stuttering, new coils may eliminate the same. See if your mechanic can try replacement coils from some other vehicle, just for trial. And anyway, changing the ignition coil at 1 lakh km isn't overkill. I changed the coils in my SX4 at 1.25 lakh km even though I did not have problems. The old coils are preserved as spare.
3. Worn out timing belt will cause more severe problems like loss of compression, engine stalling. And once the belt slips, it is not going to align itself again to a perfect position, so the problem will be experienced all the time.
4. Santro is a very good vehicle with a very good engine. Yours will be Santro Zing I guess. It shall easily last beyond 2 lakh km if it has been maintained properly. So no need to change the car just for stuttering.

I don't know about Chennai. But Mumbai has a large population of Santro in the taxi market. If Chennai too has Santro taxis, typical garage who services them (very few are likely to visit the authorised SS) shall be able to diagnose the issue outright.

Fuel pump could also be the culprit. But throttle body is unlikely to be the problem. By the way, do you observe any connection between low fuel level and stuttering?

[Newtown]

Originally Posted by Rahul Bhalgat

the vehicle started to stutter.

Did they check if the intake manifold has any leaks? This could certainly cause it to stutter.

[Tamarind]

Originally Posted by Rahul Bhalgat

Try injector cleaners like Addon P. You might be aware that these are to be put in the fuel tank in a certain proportion. Consume two tankfulls. Clogged injectors may cause uneven stuttering. This will hardly cost anything and won't be a wastage anyway.

Nope. Can you pls link me to some good articles / videos to know how to use these for Santro ?

Originally Posted by Rahul Bhalgat

If new sparkplugs reduced stuttering, new coils may eliminate the same. See if your mechanic can try replacement coils from some other vehicle, just for trial. And anyway, changing the ignition coil at 1 lakh km isn't overkill. I changed the coils in my SX4 at 1.25 lakh km even though I did not have problems. The old coils are preserved as spare.

How much do these coil spare & replacement labor usually cost us ?

Originally Posted by Rahul Bhalgat

Worn out timing belt will cause more severe problems like loss of compression, engine stalling. And once the belt slips, it is not going to align itself again to a perfect position, so the problem will be experienced all the time

The mechanic says, the pre tensioners will have to be changed with belt. Both will cost 6k with labor - Is this a reasonable price for Santro ?

Originally Posted by Rahul Bhalgat

Santro is a very good vehicle with a very good engine. Yours will be Santro Zing I guess. It shall easily last beyond 2 lakh km if it has been maintained properly. So no need to change the car just for stuttering.

I don't know about Chennai. But Mumbai has a large population of Santro in the taxi market. If Chennai too has Santro taxis, typical garage who services them (very few are likely to visit the authorised SS) shall be able to diagnose the issue outright.

Fuel pump could also be the culprit. But throttle body is unlikely to be the problem. By the way, do you observe any connection between low fuel level and stuttering?

Yes - Santro Xing,

No Santro taxis in Chennai like in Mumbai. The mechanic is not able to find another vehicle to change spares for testing - hence he wants to buy and try it out :( (May be will have to lookout for some other garage),

The tank was 80% full when the problem occured and is now half full with the same problem. May be i will try filling it 100% for eliminating this source as well tomorrow

[Rahul Bhalgat]

Originally Posted by Tamarind

Nope. Can you pls link me to some good articles / videos to know how to use these for Santro ?

There is a separate thread on fuel additives on T-BHP. Typical dosage of Adon P is around 1 ml per liter of fuel IIRC. The dosage and directions for use are also given on the sachet / bottle.

Originally Posted by Tamarind

How much do these coil spare & replacement labor usually cost us ?

Ignition coil is fairly easy to replace, it is on the top of the engine. There is just a cover (and airbox in some cars) above the coils. It is a job of 15 - 20 minutes. A small mechanic can do it for ₹ 100 - 150. There is no risk in doing it from him or some good FNG, which may charge around ₹150 - 200.

Originally Posted by Tamarind

The mechanic says, the pre tensioners will have to be changed with belt. Both will cost 6k with labor - Is this a reasonable price for Santro ?

Yes, the belt tensioner also needs to be changed. If needed, do not hesitate to change any of the pulleys. Also check the water pump, which is driven by the same belt.

Originally Posted by Tamarind

Yes - Santro Xing,

No Santro taxis in Chennai like in Mumbai. The mechanic is not able to find another vehicle to change spares for testing - hence he wants to buy and try it out :( (May be will have to lookout for some other garage),

I understand. Then I recommend the following order:
Fuel line leaks - Fuel filter (if not changed in last 20,000 km) - Adon P - Ignition coils - Fuel pump (take out and test first, before replacing).

Originally Posted by Tamarind

The tank was 80% full when the problem occured and is now half full with the same problem. May be i will try filling it 100% for eliminating this source as well tomorrow

Then it isn't a problem with fuel level. No need to try with 100% full tank. If the fuel pump is found culprit, get the tank removed and cleaned too.

[Tamarind]

Originally Posted by Rahul Bhalgat

There is a separate thread on fuel additives on T-BHP. Typical dosage of Adon P is around 1 ml per liter of fuel IIRC. The dosage and directions for use are also given on the sachet / bottle.

Are you referring to this thread (The Fuel Additives Thread) ?

Ignition coil is fairly easy to replace, it is on the top of the engine. There is just a cover (and airbox in some cars) above the coils. It is a job of 15 - 20 minutes. A small mechanic can do it for ₹ 100 - 150. There is no risk in doing it from him or some good FNG, which may charge around ₹150 - 200.

Gotcha - will try it out

Yes, the belt tensioner also needs to be changed. If needed, do not hesitate to change any of the pulleys. Also check the water pump, which is driven by the same belt.

Water pump ? The pump to push out windscreen washer liquid ?
As i type, i recollect that just before entering the S bend the last thing i did was to clean the windscreen with the washer !
Does this have any relevance to the current problem ?

I understand. Then I recommend the following order:
Fuel line leaks - Fuel filter (if not changed in last 20,000 km) - Adon P - Ignition coils - Fuel pump (take out and test first, before replacing).

Fuel pump was tested by Hyundai service and said its working fine. But my mechanic says, they would have taken out and tested which gives full 12 V, but actually when immersed inside the tank, the voltage via the electronics might reduce the voltage being supplied .....etc. So will have to replace and check with a new one

Whats your take on this ?

[Rahul Bhalgat]

Originally Posted by Tamarind

Are you referring to this thread (The Fuel Additives Thread) ?

Yes. It is a pretty long thread. You may just go through last 6 - 8 pages.

Originally Posted by Tamarind

Water pump ? The pump to push out windscreen washer liquid ?
As i type, i recollect that just before entering the S bend the last thing i did was to clean the windscreen with the washer !
Does this have any relevance to the current problem ?

What you are referring to, is the windshield washer pump. Water pump circulates the coolant through the engine and the radiator.

Originally Posted by Tamarind

Fuel pump tested by Hyundai service and said its working fine. But my mechanic says, they would have taken out and tested which gives full 12 V, but actually when immersed inside the tank, the voltage via the electronics might reduce the voltage being supplied .....etc. So will have to replace and check with a new one

If Hyundai SS has checked the fuel pump, I expect it to be alright. If the pump isn't getting 12 volts fully and uninterrupted, then get the fuel pump wiring and connectors checked. Also get the battry voltage checked. The mechanic will check when the engine is ON and when it is idling.

[Keneida]

Change the injectors 5-6K approx. cost. 10% blend fuel clogs the injectors of BS2-3-4 vehicles.

[jnanesh]

We faced a similar issue with our old WagonR a couple of years ago, it started after the engine bay area was sprayed without covering the ignition coils. It stuttered at mostly at pickup speeds ~20 to 40kmph and was smooth beyond 50kmph.

We too changed the spark plugs(with a local mechanic) which reduced the intensity and frequency of the stuttering but didn't go away completely after which we took it to a MASS. They put on the ignition coils of another WagonR temporarily to check if that was the cause, it was, Both ignition coils were changed and the issue was resolved for good.

[kvsneela]

There is no direct solution for these kind of problems. Since the car is 13 years( and 1 lakh km) old , all the old compenents might be losing their efficiency and these are ( sputtering and dying) is the symptom. But which component is the difficult to pinpoint. One side we have fuel line ( bad quality petrol, weak fuel pump and filter , clogged injectors ,etc,.) and other side air filter, in take manifold, all the sensors on the way, and then ignition system with ignition coils, sparkplugs , timing chain etc ,.
If one by one is changed we can see improvement because the old parts were not working with full efficiency. Modern IC engines can run 2 lakh kms easily but it requires support from other components with full efficiency. If the car is serviced in big dealership where they have similar models and can swap components trial and error and find the culprit. In case of FNG we have to buy new parts only ( also trail and error). If we find real problem with 10th component ,we might have replaced 9 components unnecessarily and expenditure may be more than the resale value of the car. Also since it is 2009 model , in 2 years RTO roadworthiness certificate will be required. In case of any old cars , the time to consider changing the car is the time the car starts giving major problem .