Undetectable starting problem in santro

sidindica · 26th January 2010, 11:26

I got a call from my brother that the santro is developing a starting problem, in the morning cold.

Description, as experianced by me when I went to see myself:

It takes about 5-6 cranks to start, and the engine makes a slight "bhut bhut" noise before it has to be forced to start.
when it comes to life, the motor has to be revved to get on going.
after that, the car runs absolutely normally and cranks at first stroke.
recently, the ignition coil was replaced along with new spark plug wires, yet the problem is persistent, even Hyundai service is unable to diagnose. They say to leave the car at night and they will see in the morning.
I have made a video and showed to them, yet of no avail.
I thought weather to be a problem, but our locality has 3 similar santros, all e-rlx, 2 of them have even covered more than my car and yet they do not face any problem like our car.
battery is perfectly fine.
throttle body was cleaned, yet of no avail. yesterday the motor was idling at high rpm.

What could be that hidden fault?

( I will be uploading the video in about 45 mins.)

vigsom · 26th January 2010, 11:35

There seems to be some problem with the Throttle position sensor/settings and/or feedback that the ecm is getting from the temperature sensor.

How many kms have been covered on the current plugs after last cleaning/replacement?

sidindica · 26th January 2010, 11:47

100 kms covered with new spark plugs, and less then 30 with the new ignition coil plus new plug wires. Another possibility-water inside spark plugs after a car undergoes a full wash-is ruled out as the bay engine is dry.

sidindica · 26th January 2010, 12:20

This is the video of the problem. Took it today morning.

YouTube - MOV03798.MPG

aargee · 26th January 2010, 12:31

Just one clarification, does it happen only at the first start of every morning? Does it happen when started in the evening also assuming the car hasn't been started since morning) or after every long parking? (say like when starting from the office in the evening)?

Just a thought to check a possibility, try the new ignition coils, spark plugs & spark plug wires on a different Santro.

What about the self motor? Hope you've got it checked it.

sidindica · 26th January 2010, 12:33

It happens when the car is started for the FIRST TIME on any time of the day. But mostly it is started at mornings. Once it happened at afternoon also.

aargee · 26th January 2010, 12:50

Hope you've checked the fuel pump, fuel pressure. Also if there's a way to check the engine's RPM (I'm aware Santo doesn't have), pls check if the tacho moves during the initial cranks.

gemithomas · 26th January 2010, 13:31

IS there a way o check the fuel pressure. Is it possible that the pump is unable to maintain the pressure during thirst cold start when most fluids (including fuel) have settled down over a long period. Is the pump getting activated in the first few seconds of the ignition "on"?

EDIT: Just saw the video. Also replace your tdc sensor (the one that sends information on crank shaft) with another one and check if it makes any difference.

kiranpashtakar · 26th January 2010, 14:02

This may not be of help, but could fuel quality the culprit. I cant substantiate this but I had a similar problem with my car once when I had bad quality fuel, the service centre also could not figure out but when I changed the fuel the problem vanished.

Randhawa · 26th January 2010, 14:03

Check for idling sensor, any loose connection and earth. Also check for vacuum leak on the hoses.

Jaggu · 26th January 2010, 15:19

Get the fuel lines/ filters checked first. Then see if the fuel pump is pressurizing the lines properly. Then move to injectors.

Have you tried leaving the ignition switch ON for around 5-10 seconds and then cranking?

vipul_singh · 26th January 2010, 19:58

I feel the coolant temperature sensor is sending an incorrect input to the ECU. Get the coolant temperature sensor replaced and see if the problem comes back

A very similar problem was once reported in the 'Ask Tim' section of Times Online Driving (UK).

vigsom · 26th January 2010, 20:30

A zero cost solution - reset your ECU by disconnecting battery -ve and reconnecting after say 15 minutes.Sometimes,this works.

Randhawa · 26th January 2010, 21:08

Quote:

Originally Posted by vipul_singh

I feel the coolant temperature sensor is sending an incorrect input to the ECU. Get the coolant temperature sensor replaced and see if the problem comes back

A very similar problem was once reported in the 'Ask Tim' section of Times Online Driving (UK).

I agree with you on that. If the ecu gets wrong readings from the faulty sensor then it might give lean mixture and starting in cold weather could be a problem.

I am not sure if Santro has one or two temp sensor but do get them checked out with a multimeter. You might have one on the radiator, other on the engine.

ghpk · 26th January 2010, 21:43

First ask someone to take out your petrol filter which is under the left rear door, they'll need to unscrew it then disconnect fuel line and then examine it,
some cleaning can be done by air-pressure, else it would need to be replaced.

make sure the plugs are correctly installed, normally, mechanics alter the space between electrode to suit their eye rather than recommended space.

check ignition coil which you say has been replaced,
was there this kinda problem when you got this replaced ?

bhut bhut sound may be a signal for too much carbon residue in crank, and might need de-carbonizing.

Also post, how much car has been driven in All, when was the last service done, and what were tasks done in last service.

26th January 2010, 11:26	#1
sidindica Senior - BHPian Join Date: Jun 2007 Location: Delhi Posts: 4,892 Thanked: 8,106 Times	Undetectable starting problem in santro I got a call from my brother that the santro is developing a starting problem, in the morning cold. Description, as experianced by me when I went to see myself: It takes about 5-6 cranks to start, and the engine makes a slight "bhut bhut" noise before it has to be forced to start. when it comes to life, the motor has to be revved to get on going. after that, the car runs absolutely normally and cranks at first stroke. recently, the ignition coil was replaced along with new spark plug wires, yet the problem is persistent, even Hyundai service is unable to diagnose. They say to leave the car at night and they will see in the morning. I have made a video and showed to them, yet of no avail. I thought weather to be a problem, but our locality has 3 similar santros, all e-rlx, 2 of them have even covered more than my car and yet they do not face any problem like our car. battery is perfectly fine. throttle body was cleaned, yet of no avail. yesterday the motor was idling at high rpm. What could be that hidden fault? ( I will be uploading the video in about 45 mins.) Last edited by sidindica : 26th January 2010 at 11:32.
	() Thanks

26th January 2010, 11:35	#2
vigsom Distinguished - BHPian Join Date: Feb 2006 Location: NSEW Posts: 3,759 Thanked: 25,460 Times	There seems to be some problem with the Throttle position sensor/settings and/or feedback that the ecm is getting from the temperature sensor. How many kms have been covered on the current plugs after last cleaning/replacement?
	() Thanks

26th January 2010, 11:47	#3
sidindica Senior - BHPian Join Date: Jun 2007 Location: Delhi Posts: 4,892 Thanked: 8,106 Times	100 kms covered with new spark plugs, and less then 30 with the new ignition coil plus new plug wires. Another possibility-water inside spark plugs after a car undergoes a full wash-is ruled out as the bay engine is dry. Last edited by sidindica : 26th January 2010 at 11:58.
	() Thanks

26th January 2010, 12:31	#5
aargee Senior - BHPian Join Date: Jan 2010 Location: TSTN Posts: 6,236 Thanked: 9,635 Times	Just one clarification, does it happen only at the first start of every morning? Does it happen when started in the evening also assuming the car hasn't been started since morning) or after every long parking? (say like when starting from the office in the evening)? Just a thought to check a possibility, try the new ignition coils, spark plugs & spark plug wires on a different Santro. What about the self motor? Hope you've got it checked it. Last edited by aargee : 26th January 2010 at 12:37.
	() Thanks

26th January 2010, 12:33	#6
sidindica Senior - BHPian Join Date: Jun 2007 Location: Delhi Posts: 4,892 Thanked: 8,106 Times	It happens when the car is started for the FIRST TIME on any time of the day. But mostly it is started at mornings. Once it happened at afternoon also.
	() Thanks

26th January 2010, 12:50	#7
aargee Senior - BHPian Join Date: Jan 2010 Location: TSTN Posts: 6,236 Thanked: 9,635 Times	Hope you've checked the fuel pump, fuel pressure. Also if there's a way to check the engine's RPM (I'm aware Santo doesn't have), pls check if the tacho moves during the initial cranks.
	() Thanks

26th January 2010, 13:31	#8
gemithomas Senior - BHPian Join Date: Jan 2007 Location: Trivandrum Posts: 2,366 Thanked: 143 Times View My Garage	IS there a way o check the fuel pressure. Is it possible that the pump is unable to maintain the pressure during thirst cold start when most fluids (including fuel) have settled down over a long period. Is the pump getting activated in the first few seconds of the ignition "on"? EDIT: Just saw the video. Also replace your tdc sensor (the one that sends information on crank shaft) with another one and check if it makes any difference. Last edited by gemithomas : 26th January 2010 at 13:36.
	() Thanks

26th January 2010, 14:02	#9
kiranpashtakar BHPian Join Date: Aug 2005 Location: Bangalore/Hyderabad Posts: 257 Thanked: 7 Times	This may not be of help, but could fuel quality the culprit. I cant substantiate this but I had a similar problem with my car once when I had bad quality fuel, the service centre also could not figure out but when I changed the fuel the problem vanished.
	() Thanks

26th January 2010, 14:03	#10
Randhawa Senior - BHPian Join Date: Oct 2007 Location: Brighton Posts: 1,192 Thanked: 355 Times	Check for idling sensor, any loose connection and earth. Also check for vacuum leak on the hoses. Last edited by Randhawa : 26th January 2010 at 14:06.
	() Thanks

26th January 2010, 15:19	#11
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,904 Times	Get the fuel lines/ filters checked first. Then see if the fuel pump is pressurizing the lines properly. Then move to injectors. Have you tried leaving the ignition switch ON for around 5-10 seconds and then cranking?
	() Thanks

26th January 2010, 19:58	#12
vipul_singh BHPian Join Date: Sep 2005 Location: BLR / Lucknow Posts: 595 Thanked: 833 Times View My Garage	I feel the coolant temperature sensor is sending an incorrect input to the ECU. Get the coolant temperature sensor replaced and see if the problem comes back A very similar problem was once reported in the 'Ask Tim' section of Times Online Driving (UK).
	() Thanks

26th January 2010, 20:30	#13
vigsom Distinguished - BHPian Join Date: Feb 2006 Location: NSEW Posts: 3,759 Thanked: 25,460 Times	A zero cost solution - reset your ECU by disconnecting battery -ve and reconnecting after say 15 minutes.Sometimes,this works.
	() Thanks

26th January 2010, 21:43	#15
ghpk BHPian Join Date: Mar 2009 Location: Ghaziabad Posts: 870 Thanked: 211 Times	First ask someone to take out your petrol filter which is under the left rear door, they'll need to unscrew it then disconnect fuel line and then examine it, some cleaning can be done by air-pressure, else it would need to be replaced. make sure the plugs are correctly installed, normally, mechanics alter the space between electrode to suit their eye rather than recommended space. check ignition coil which you say has been replaced, was there this kinda problem when you got this replaced ? bhut bhut sound may be a signal for too much carbon residue in crank, and might need de-carbonizing. Also post, how much car has been driven in All, when was the last service done, and what were tasks done in last service.
	() Thanks