[vcash]

Guys - Still need your help. My mechanic is having a tough time diagnosing the problem. He is now taking shots in the dark, the latest one being that the ICV mechanism inside the throttle body is not opening and closing properly and might need replacement if he cannot fix it. Does this sound right to anyone?

[jerry can]

Have you got the Throttle Position Sensor (TPS) checked? Sometimes this sensor starts malfunctioning and as a result, correct throttle input from the accelerator does not reach the ECU. Also get ECU itself checked.
One more thing, check the fuel lines and the fuel filter again for dirt and sludge, if they are dirty again then it could be that there's lots of sludge/dirt in the fuel tank, and the filter mesh (if there's any) in the fuel tank is damaged. In this case the dirt would be regularly clogging up the fuel lines in short succession causing the frequent stalls.

[ravikn]

@vcash,

Talk to Venkatesh from Gowri Automobiles(9379192193). If you speak in Hindi, he will be able to help you. Explain him the problem first and do not tell anything that ur mechanic have told you so far. Am sure his diagnosis of the problem will be better and help you get the problem fixed.

[drpullockaran]

Check the fuel pressure with a gauge while the vehicle is being normally used which means a long strong tube to your gauge inside the car if the problem is not immediately experienced. The pressure should be with in limits.
Also do check for the functioning of the stepper motor of the idling actuator. Get back to me after this. Please rule out the lambda sensor as I could drive my car without lambda sensor leads plugged in quite easily.

[vcash]

Thanks for all the inputs!

I got my car back on Friday. According to the the mechanic, the fuel lines and ignition coil were checked and there was no issue with these. Fuel pump also seemed to be working okay.

The mechanic told me that the ICV was 'serviced' as opposed to being cleaned this time around. Aparently, he had just opened it last time and cleaned it externally, where as this time he took out the whole assembly and removed a lot of carbon from the valve.

He said the car should be fine and that I should try and keep atleast 10L in it at any given time. I filled her up and drove the car for around 10 KMs on Friday. It seemed much smoother than before save for one instance of jerking and one instance of rpm meter self revving itself.

I did not have an opportunity to drive the car on Saturday or Sunday and this morning sat in the car for the first time since the weekend. Today was a slightly cooler day in Mumbai and I tried starting the car. First crank it starts and then it dies within 2 seconds. After that I must have tried to fire her up atleast 20 times with no avail. A small sputter for half a second and then nothing!

I am really at my witts end now. What should I do? Thinking of dropping of the car at Mahindra First Choice or Concorde Motors.

Cheers,
V

[planet_rocker]

do the injector light glow when:

1. engine starts?
2. fires up, sputters and dies?

Did they pressure wash the engine bay? if yes, was the ECU covered?

Did they check the Crank Position Sensor? It is located near the crank pulley (towards the bottom of the engine / LHS when you are facing the engine) - costs around Rs. 2000/-

Try and reset the ECU by disconnecting the negative terminal for more than 30 mins. Also disconnect the other wires connecting to the ECU - unscrew the ECU from the holder, pull it out - check for water deposits at the terminals - use hair drier (normal flow) to dry up the moisture and plug it back - see if problem occurs / car starts. check if the black round water seal is present on metal plate of the ECU.

I hope the battery health is good / ok.

[vcash]

Originally Posted by planet_rocker

do the injector light glow when:

1. engine starts?
2. fires up, sputters and dies?

Did they pressure wash the engine bay? if yes, was the ECU covered?

Did they check the Crank Position Sensor? It is located near the crank pulley (towards the bottom of the engine / LHS when you are facing the engine) - costs around Rs. 2000/-

Try and reset the ECU by disconnecting the negative terminal for more than 30 mins. Also disconnect the other wires connecting to the ECU - unscrew the ECU from the holder, pull it out - check for water deposits at the terminals - use hair drier (normal flow) to dry up the moisture and plug it back - see if problem occurs / car starts. check if the black round water seal is present on metal plate of the ECU.

I hope the battery health is good / ok.

Battery is a little over a month old. The car engine bay has not been washed in over a year. How does one check the Crank Position Sensor - Does it need to be connected to a diagnostic? I think I ought to take the car to a more modern service center to get a diagnosis done.

[planet_rocker]

The crank position sensor health should come up on a scanner - visually it is a black wire (about an arms length)

I am sure that MUM has better FIAT ASC with a scanner.

Do the ECU reset tonight - (keep the negative terminal disconnected and away from metal contact for the whole night or more than 30minutes) - Connect the terminal and see if the car behaves properly - the cabin clock and HU settings will be lost.

EDIT: please let us know if the injector lights glows when the problem occurs

[vcash]

Originally Posted by planet_rocker

The crank position sensor health should come up on a scanner - visually it is a black wire (about an arms length)

I am sure that MUM has better FIAT ASC with a scanner.

Do the ECU reset tonight - (keep the negative terminal disconnected and away from metal contact for the whole night or more than 30minutes) - Connect the terminal and see if the car behaves properly - the cabin clock and HU settings will be lost.

EDIT: please let us know if the injector lights glows when the problem occurs

Injector light does not glow when the problem occurs.

I just got home and upon the 5th crank, the car started but was accompanied by shuddering and bouncy RPM. After trying to idle her for a few minutes, I took her for a short spin - Same loss of power (Accelerator fully down) and rev below 1K. Then rev stopping at 2K - Finally after a few cycles like this, it seems that the choking sensation cleared and the car drives fine.

Come back and the car idles perfectly before I switched her off (It almost seems that as the engine reaches optimum temperature the problem disappears but I could be wrong)

Here are a few videos to demonstrate the issue:

1) After Initial Crank - Bouncy RPM, Shuddering, Auto Shutting off.

YouTube - After Initial Crank.mp4

2) Revving but getting stuck around 4K for a brief second and then switching itself off.

YouTube - Revving but get stuck at 4K.mp4

3) Perfect Idle and Rev post 10 minute drive.

YouTube - Perfect Idle post drive.mp4

Losing my mind with this!!

Cheers,
V

[planet_rocker]

Originally Posted by vcash

Injector light does not glow when the problem occurs.

that is a good sign in a way.

Originally Posted by vcash

I just got home and upon the 5th crank, the car started but was accompanied by shuddering and bouncy RPM. After trying to idle her for a few minutes, I took her for a short spin - Same loss of power (Accelerator fully down) and rev below 1K. Then rev stopping at 2K - Finally after a few cycles like this, it seems that the choking sensation cleared and the car drives fine.

was the timing belt was changed recently in this car - ask the mechanic to check the crank sensor again. the crank sensor is also known as RPM sensor [TDC sensor and Cam sensor are the same thing - FYI only]- i have a feeling that the crank sensor is at fault. the problem occurs when the car is cold and problem reduces when the car has warmed up.

Originally Posted by vcash

Come back and the car idles perfectly before I switched her off (It almost seems that as the engine reaches optimum temperature the problem disappears but I could be wrong)

if you can go to the car and restart - let it idle till the fan turns on couple of times - again - let it idle (Avoid Revving the car like that).

Originally Posted by vcash

1) After Initial Crank - Bouncy RPM, Shuddering, Auto Shutting off.

car is still cold and when it warms up ...

Originally Posted by vcash

2) Revving but getting stuck around 4K for a brief second and then switching itself off.

is that you revving the car or is the revving on its own? Search for "italian tune-up"

Originally Posted by vcash

3) Perfect Idle and Rev post 10 minute drive.

you should have let it warm up more - wait till the fan turns on couple of times. that is not optimum temperature as per the temperature needle

Originally Posted by vcash

Losing my mind with this!!

Cheers,
V

don't lose hope - she is a fine specimen - do the ECU reset thingy once - check for water droplets near the exhaust pipe.

EDIT: was going through the thread and found this:

Originally Posted by drpullockaran

Remote possibilities are the rpm sensor and the TDC sensor.

- get it checked as a measure

[vcash]

was the timing belt was changed recently in this car - ask the mechanic to check the crank sensor again. the crank sensor is also known as RPM sensor [TDC sensor and Cam sensor are the same thing - FYI only]- i have a feeling that the crank sensor is at fault. the problem occurs when the car is cold and problem reduces when the car has warmed up.

No - The timing belt was not changed but the Aux belt (Fan, PS, AC) were changed - A slightly larger belt was installed because the original smaller belt that runs the fan and PS etc. was not available.

if you can go to the car and restart - let it idle till the fan turns on couple of times - again - let it idle (Avoid Revving the car like that).

I was only revving it to demonstrate the problem. Typically the fan does come on after I switch the car off.

is that you revving the car or is the revving on its own? Search for "italian tune-up"

Upto 4K and beyond- it is me revving it but sometimes the auto rev goes up to 3K on its own.

you should have let it warm up more - wait till the fan turns on couple of times. that is not optimum temperature as per the temperature needle

So typically, when I am driving in traffic for over 20 mins, the temp indicator hits just below the half way mark. But moment the road opens up she falls to the 1/4th mark. I do notice less problems when she is around the half way mark.

don't lose hope - she is a fine specimen - do the ECU reset thingy once - check for water droplets near the exhaust pipe.

Will try this tom and check for water droplets. Will also go to Mahindra First Choice or Tata-Fiat and get the sensors checked out.

Cheers,
V

[vipul_singh]

@vcash: jumping into the thread late, and honestly, I have not read the thread in its entirity. I'd just like to say this: for each sensor feeding into the ECU, there are very specific (and simple) test defined in the vehicle's service manual. So if I were you, I would ask the mechanic to carry out those specific tests, instead of changing sensors left, right and center

Edit: again, my comments might sound like a wild goose chase, but can you check if air is entering into the intake manifold after the throttle body? This is known to cause the kind of RPM issues you have indicated.

[drpullockaran]

Get hold of a spare ECU of the 1.6 engine and use it for 1 week and ascertain whether the problem repeats itself.

I repeat get hold of a spare ECU. Get hold of a spare ECU.

Please read the PDF engineering service manual.

[planet_rocker]

Originally Posted by drpullockaran

. Get hold of a spare ECU.

Please read the PDF engineering service manual.

getting hands on a spare ECU is going to be tough. where did you find the PDF workshop service manual?

Originally Posted by vipul_singh

So if I were you, I would ask the mechanic to carry out those specific tests, instead of changing sensors left, right and center

No sensors were changed i guess

Originally Posted by vipul_singh

Edit: again, my comments might sound like a wild goose chase, but can you check if air is entering into the intake manifold after the throttle body? This is known to cause the kind of RPM issues you have indicated.

you mean in between the throttle body and the inlet manifold? if that is the case - wouldn't it affect the normal idle all the time?

Originally Posted by vcash

No - The timing belt was not changed but the Aux belt (Fan, PS, AC) were changed - A slightly larger belt was installed because the original smaller belt that runs the fan and PS etc. was not available.

I guess it is better to change the timing belt as a precautionary measure (may be on a later date)

the other belts / Alternator / PS / AC - i don't think these are related to this specific problem.

Originally Posted by vcash

I was only revving it to demonstrate the problem. Typically the fan does come on after I switch the car off.

fan will remain on only when the car is hot after switching off the car.

Originally Posted by vcash

So typically, when I am driving in traffic for over 20 mins, the temp indicator hits just below the half way mark. But moment the road opens up she falls to the 1/4th mark. I do notice less problems when she is around the half way mark.

its normal - no issues.

Originally Posted by vcash

Will try this tom and check for water droplets. Will also go to Mahindra First Choice or Tata-Fiat and get the sensors checked out.

why not a FIAT ASC?

[vcash]

No sensors were changed i guess

Other than the speed sensor last year - None.

you mean in between the throttle body and the inlet manifold? if that is the case - wouldn't it affect the normal idle all the time?

My mechanic who worked on the car last still insists that it is the throttle body control that needs to be changed - Between 5K and 13K is what he is asking!

I guess it is better to change the timing belt as a precautionary measure (may be on a later date)

Yup will do.

fan will remain on only when the car is hot after switching off the car.

Yup. Just wanted to ensure that the fan was working.

why not a FIAT ASC?

Concorde Motors (COCO workshop) has stopped repairing Palio's. Have heard some horror stories from my colleagues about the other ASC (Wasan) and Fortune is very far (Almost 2 hours away).

MFC has a diagnostic tool and said that they will check each component and take one day to diagnose. These guys might be thorough (I hope!)