[srvm]

Originally Posted by srvm

Sharing my experience over the last month for others benefit.
....
.....
The parts highlighted in bold were the key data / information to figuring out the possible culprit. I hope the starting troubles are behind me.

Lessons learned:
1. Stay calm and think about the circumstances that cause unusual behavior of the car.
2. Read the user manual.
3. Carry useful tools in the boot. Don't hesitate to get your hands dirty, if needed.
4. Simple electrical faults (such as blown fuses) are somewhat easy to diagnose and solve. I have seen numerous examples of friends/neighbors requiring help of a mechanic to replace a punctured tyre!
....

I thought my fuel-pump and electrical troubles were over. But issues have resurfaced again.

On the evening of 10th July, in rush hour crawling traffic, my car stopped on the Nagavara flyover and did not start despite many attempts. It was towed to Authorized Service Center (Adishakti Motors). SA delivered the car after 3-4 days saying they did 30km test drive but could not replicate the problem. According to them, OBD scan results (which they failed to show/share with me) showed up two memorized faults: (1) Fuel pump malfunction (2) Something related to ECU / engine wiring harness.

The car starts and functions well during cold-starts. SA told me that if the problem recurs, then they would change Engine wiring harness. (Fuel pump was changed in Sep-2022 only hence less-likely to be the culprit). On the whole, another sub-standard experience with service center. This is an expensive repair and I'm not sure about their diagnosis.

On 5th August, once again while crawling in stop-go traffic, the car stalled and refused to start for few minutes. Traffic piled up in no time behind me and I was nervous. After multiple attempts, the car started and I reached home without further problems (< 2 kms distance).


In summary,
1. This sudden stalling and refusal to start immediately thereafter seems to happen only while in stop-and-go crawling traffic.

2. The engine bay feels hotter than usual when this happens. Though the temperature sensor reading in the instrument cluster shows 3-bars which is normal operating temp in my car (max temp = 6-bars).

3. There is no leakage of coolant under the car. Coolant levels haven't changed/dropped.

What could be the problem here? I'm now nervous to take the car in peak-office hours / crawling traffic (which is common in Bangalore).

Should I suspect some vapor lock in the fuel lines when the engine bay heats up? Is it some malfunction in the wiring harness/electricals (relays or ignition coils or temperature sensor etc)? Or is the fuel-pump kaput again? Or is it related to the previous issue (see my quoted posted from June)?

If it helps, my car has a Turbo-charged gasoline MPFI engine.

Any help in this matter is much appreciated.

[Aroy]

Originally Posted by srvm

.................
Should I suspect some vapor lock in the fuel lines when the engine bay heats up? Is it some malfunction in the wiring harness/electricals (relays or ignition coils etc)? Or is the fuel-pump kaput again? Or is it related to the previous issue (see my quoted posted from June)?

If it helps, my car has a Turbo-charged gasoline MPFI engine.

Any help in this matter is much appreciated.

I also suspect vapour lock. That can be due to a variety of reasons
. A microscopic leak around the fuel pump.
. The breathing hole on the fuel cap clogged.

If it is around the fuel pump then do what us old timers did during the 60's and 70's - put a wet cloth around the fuel pump to cool it. Once cooled the car sould start if the problem is around the pump. If not check the fuel cap and clean the hole on it.

[NomadSK]

Originally Posted by srvm

In summary,
1. This sudden stalling and refusal to start immediately thereafter seems to happen only while in stop-and-go crawling traffic.

2. The engine bay feels hotter than usual when this happens. Though the temperature sensor reading in the instrument cluster shows 3-bars which is normal operating temp in my car (max temp = 6-bars).

3. There is no leakage of coolant under the car. Coolant levels haven't changed/dropped.

What could be the problem here?

As per the explanation given, I would rule out the fuel pump since it was replaced almost a year ago. And also the car behaves like this only during slow/crawling traffic. I would look in the direction of something related to the “temperature”. Was your radiator fan working when the engine stalled in the traffic ?

Since there is no change in the coolant level, First thing I would look at all the thermostats and the sensors related to the heating of the engine and the cooling system of the car to troubleshoot. And I would start the procedure from radiator fan working to also checking of the coolant temperature sensor. A malfunctioning coolant temperature sensor may send an incorrect signal to the ECU, causing the engine to overheat which in turn can create the vapor lock in fuel lines. A faulty coolant sensor can give incorrect data to the ECU. It is a two-wire thermistor immersed in coolant and measures its temperature. Since it’s location is inside the coolant, it’s a harsh environment and loose circuit or corrosion can damage the sensor.

Vapor lock can also happen due to the increase in temperature in fuel system with engine overheating. Check for insulation of the fuel lines and if they are away from all the heating elements or well protected, from exhaust line, catcon and in the engine bay.

These would be the initial steps to rule out any temperature related issue.

[Jeroen]

Originally Posted by srvm

Should I suspect some vapor lock in the fuel lines when the engine bay heats up? Is it some malfunction in the wiring harness/electricals (relays or ignition coils or temperature sensor etc)? Or is the fuel-pump kaput again? Or is it related to the previous issue (see my quoted posted from June)?

If your car has fuel injection the chances of Vapor lock are about 0%! Vapour lock is something from the old days, carburettors, Lucas wonky electrics. On a pressurised system it is very unlikely to happen.

Next time it happens, make sure they share screen shots of the codes they find when hooked up to a proper OBD scanner.

Without a proper OBD scan, it is just impossible to tell. Anybody that tells you differently and offers solutions, doesn’t understand how modern engines work I’m afraid.

High temperatures under the hood, do not cause Vapor lock in a fuel injection system. It’s pressurised, so its boiling point is way higher.

Engines never ever shut down due to a sensor picking up a high temperature. It would be unsafe. There are some sensors that sometimes give issues when getting very hot. Crankshaft and camshaft sensors might behave oddly when old and hot. Again, an OBD scan will, most likely, tell.

Good luck

Jeroen

[Rev2Serenity]

Dear All,

I'm reaching out to you for a peculiar starting problem of my petrol 2015 Hyundai I20 Active S steed. Randomly without any pattern which I could notice, the car doesn't start. Initially I thought it to be a weak battery, so, replaced the battery but the problem persists. Once the ignition is switched on, the car cranks but doesn't fire up. I have found a solution now by just not letting off the ignition. After long cranking, the car does fire up but the tachometer needle will stay at zero and not at idling rpm. Press the accelerator, the engine responds, never tried to move the car in this situation. Immediately switching off and firing again will start the car normally.

Authorized service center technicians experienced this once in a weeklong observation but couldn't find any error codes. A supervisor at Advaith Hyundai opines it to be crankshaft positioner sensor (CKP Sensor?) problem but hesitant to replace the part unless sure. A video is attached as well if it helps. At 09 secs, one can notice the engine firing up but rpm at zero.

http://www.youtube.com/watch?v=58eLh...l=Chinmayhegde

The car is used majorly for weekend highway runs and off lately I'm worried about car not starting in a remote place! Should I just replace the said sensor blindly or check this again in any friendly garage.
Surprised and frustrated that with so much technology around, ASC guys are unable to pinpoint the problem. Too much dependency on the error codes I suppose! Any suggestions for a good FNG in Bangalore will be helpful.


Regards,

[srvm]

Originally Posted by srvm

I thought my fuel-pump and electrical troubles were over. But issues have resurfaced again.

On the evening of 10th July, in rush hour crawling traffic, my car stopped on the Nagavara flyover and did not start despite many attempts. It was towed to Authorized Service Center (Adishakti Motors). SA delivered the car after 3-4 days saying they did 30km test drive but could not replicate the problem. According to them, OBD scan results (which they failed to show/share with me) showed up two memorized faults: (1) Fuel pump malfunction (2) Something related to ECU / engine wiring harness.
.......
Any help in this matter is much appreciated.

Originally Posted by Aroy

I also suspect vapour lock. That can be due to a variety of reasons
. A microscopic leak around the fuel pump.
. The breathing hole on the fuel cap clogged.
......

Originally Posted by NomadSK

As per the explanation given, I would rule out the fuel pump since it was replaced almost a year ago. And also the car behaves like this only during slow/crawling traffic. I would look in the direction of something related to the “temperature”. ...........
These would be the initial steps to rule out any temperature related issue.

Originally Posted by Jeroen

If your car has fuel injection the chances of Vapor lock are about 0%! Vapour lock is something from the old days, carburettors, Lucas wonky electrics. On a pressurised system it is very unlikely to happen.
.............
Good luck

Jeroen

I have an update. Thank you Aroy, NomadSK, Jeroen.

The car stopped again on the night of 13th August in cool weather. But engine bay was quite hot. Now, I was sure it is related to temperature sensor. Wrapped wet towel over coolant pipe for about 15 minutes. After this car started again and I gingerly drove home (about 3 km away). Next morning, cold engine started like nothing happened the previous night. I drove straight to garage and explained everything to technician.

As some of you suggested, the coolant temperature sensor seems to have been the culprit. Removed and cleaned it and put it back. Idled the car for more than 45 minutes, simulated crawling traffic and all seems to be fine. Have driven nearly 300km since then and no problems so far whether engine is cold or hot.
Diagnosis: Coolant temperature sensor showing lower temperature than actual (due to slight corrosion) and hence radiator fan did not kick in on time. Leading to hotter engine and engine bay. Now fans seems to be kicking on as expected and hence no problems since then.

Will keep an eye for another 1000km and update here. No expensive wiring changes as suggested by authorized service center. Only ₹300 spent.
Thank you folks

[srvm]

Originally Posted by srvm

I have an update. Thank you Aroy, NomadSK, Jeroen.
......
Diagnosis: Coolant temperature sensor showing lower temperature than actual (due to slight corrosion) and hence radiator fan did not kick in on time. Leading to hotter engine and engine bay. Now fans seems to be kicking on as expected and hence no problems since then.

Will keep an eye for another 1000km and update here. No expensive wiring changes as suggested by authorized service center. Only ₹300 spent.
Thank you folks

Just a happy update after 1 month and 1600kms of running. No starting or overheating problems since the last post. Looks like the problem is resolved for good

[carboy]

I left my car headlights on overnight & drained the battery (4 years old battery). Got it jump started but even after driving for 10 minutes when I shut it down, it refused to start again. Is the battery dead? Should I just get a new battery or is there a point in trying to bench charge it. My driving over 4 years has been minimal. Once a week & less than 250 kms a month.

[Jeroen]

Originally Posted by carboy

I left my car headlights on overnight & drained the battery (4 years old battery). Got it jump started but even after driving for 10 minutes when I shut it down, it refused to start again. Is the battery dead? Should I just get a new battery or is there a point in trying to bench charge it. My driving over 4 years has been minimal. Once a week & less than 250 kms a month.

If the battery was completely drained, a ten minute drive is not sufficient to charge the battery sufficiently.

You should get the battery tested for remaining capacity. That is the only way to get a feel for whether it needs replacing.

You could of course just bench charge it and see what happens. I would prefer to know rather than to take a hot or miss approach.

Jeroen

[carboy]

Originally Posted by Jeroen

If the battery was completely drained, a ten minute drive is not sufficient to charge the battery sufficiently.

How much time would be required?

[GTE]

Originally Posted by carboy

I left my car headlights on overnight & drained the battery (4 years old battery). Got it jump started but even after driving for 10 minutes when I shut it down, it refused to start again. Is the battery dead? Should I just get a new battery or is there a point in trying to bench charge it. My driving over 4 years has been minimal. Once a week & less than 250 kms a month.

It's a no brainer get the battery replaced. If it was drained when newer, that could be okay. Not worth the stress.

[Aroy]

Originally Posted by carboy

How much time would be required?

At least 1 hour.

In such case, it is best to charge the battery at home. Modern chargers have a "repair" mode, that repairs some damage due to excessive discharge. It takes more than 12 hours though.

https://www.amazon.in/gp/product/B09...?ie=UTF8&psc=1

I bought this and did a good job of repairing my 5 year old batter that had discharged itself.

[rrsteer]

Originally Posted by SS-Traveller

If you hear an audible "click", but the motor doesn't turn over:[list][*]The starter motor solenoid (relay) is actuating, but the Bendix gear is perhaps jammed up against the ring gear. Place the car in 3rd / 4th gear and push / rock the car backwards to release the Bendix from the ring gear. You'll hear an audible click as the car moves backwards a little, in case the Bendix has actually jammed against the ring gear (usually caused by broken/worn teeth in the Bendix or ring gear). Try starting the car again. Warning:

Dear SS-Traveller, your thread was a saviour today. Our Etios, parked on the side of a busy road, wouldn't start today evening. My mother and wife had taken the car out for a trip to the local market. It was already dark and being a Sunday, they couldn't arrange for a mechanic. What made matters worse was that a few helpful souls thinking the car could be pushed start - pushed it, failed and then push-parked it in a way that it ever so slightly blocked the busy road.

My wife is usually self-sufficient and quite adept in managing such situations. Her frantic calls to me indicated that she had exhausted her options and was getting worried. While listening to her on the phone, my brain was screaming Team-Bhp! I had read this thread earlier and had made a mental note about it. While still on the call with her, I coolly opened this thread, and using the very well laid out charts, guided my wife as follows: Won't start --> Electricals -->All Systems appear live -->Crank starter --> Click noise heard, but motor doesn't turn --> Place the car in 3rd / 4th gear and push / rock the car backwards --> Try starting the car again --> Zoom away while being amazed at the skills of your husband!

My mother and wife were absolutely stunned as to high quickly I could diagnose the problem. But more importantly, this saved us so much harassment. So my big thanks to you SS-Traveller and also to Team-Bhp. This platform just doesn't ceases to amaze me.

[Rev2Serenity]

Originally Posted by Rev2Serenity

Dear All,

I'm reaching out to you for a peculiar starting problem of my petrol 2015 Hyundai I20 Active S steed.

Request all experts to have a look at the above problem. Unable to understand what has gone wrong in my car.

Regards,

[PGA]

Originally Posted by Rev2Serenity

Request all experts to have a look at the above problem. Unable to understand what has gone wrong in my car.

Regards,

If it was an old car, i would have said get your distributor cleaned. But since its a new gen car, to me it seems an electrical/ electronic problem and may have many reasons from malfunctioning sensors to ECU itself. Best is to take it to an auto electrician, not A.S.S, he will certainly figure it out.