stalling issue

[Essien]

Hello! Please I have a space star with a Gdi 1.8 4g93 model engine with a stalling problem. I just fix the timing belt and valve, and since then, have lost the idle running. The engine starts and dies immediately unless I accelerate it and once my leg is off the pedal,the engine dies.

I have checked the MAF flow meter,fuel pump throthle but still the same.please I need help.Thank you

[Twin Turbo]

What's your idle speed?

[Davy]

Hi Essien, welcome to the forum!

Assuming the timing belt and valve replacement has been done properly, it could be that your Throttle Position Sensor needs adjustment. From memory, I remember the Mitsubishi 1.8 GDI engines having an adjustable TPS as well as a very bulky idle air control mechanism. I'd advise you to get the throttle body properly inspected first. It may even be something as simple as a disconnected/leaking  vacuum line that's causing the engine to die. Then get the TPS adjusted and observe if that results in a stable idle. 

Just out of curiosity, why were the valves replaced? Is it due to the inherent carbon deposit issue on GDI engines? 

 

  On 3/10/2018 at 1:28 AM, Twin Turbo said:

What's your idle speed?

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It doesn't idle. "Idle speed" is zero. 

[Essien]

 

Edited March 10, 2018 by Essien
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[SXP]

Hi,
Most of the idle issues during neutral and park positions are due to a faulty IAC (or IAS as some say). This is the Idle Air Control device which controls how much air is taken in to the throttle body when throttle position is 0%

This is operated through a PWM signal from the ECU. If the device is faulty it does not let enough air to reach the engine during idle then resulting an engine stall. You cannot adjust the IAC, hence need a replacement if it's faulty and not too expensive to replace.

If IAC is working properly you here a faint hum near the throttle body

Good luck with the diagnosis.

Sent from my SM-G900F using Tapatalk

[Twin Turbo]

  On 3/10/2018 at 1:55 AM, Davy said:

Hi Essien, welcome to the forum!

Assuming the timing belt and valve replacement has been done properly, it could be that your Throttle Position Sensor needs adjustment. From memory, I remember the Mitsubishi 1.8 GDI engines having an adjustable TPS as well as a very bulky idle air control mechanism. I'd advise you to get the throttle body properly inspected first. It may even be something as simple as a disconnected/leaking  vacuum line that's causing the engine to die. Then get the TPS adjusted and observe if that results in a stable idle. 

Just out of curiosity, why were the valves replaced? Is it due to the inherent carbon deposit issue on GDI engines? 

 

It doesn't idle. "Idle speed" is zero. 

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I've seen a Vitara made to idle at 350 RPM by a local grease monkey in a bid too make it more efficient. 

[Essien]

Thank you all for this info,

The valve got damage when the timing belt was fixed wrongly so I had to fix the cylinder as a whole.

For the air control valve,I have search all around the engine but could only see something that looks like EGR valve which have removed and clean but don't know if its faulty cos its still looks good and springing well.

After all that the car still would not stop stalling and dying. Could it be the spark plug?

[Davy]

  On 3/11/2018 at 9:37 PM, Essien said:

Thank you all for this info,

The valve got damage when the timing belt was fixed wrongly so I had to fix the cylinder as a whole.

For the air control valve,I have search all around the engine but could only see something that looks like EGR valve which have removed and clean but don't know if its faulty cos its still looks good and springing well.

After all that the car still would not stop stalling and dying. Could it be the spark plug?

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As mentioned above, the IACV is on the side of the throttle body. You can't miss it because on this particular engine, it's quite bulky and the mechanism can be taken apart and cleaned unlike sealed stepper motors. Take the throttle body out, clean it, and put it back in. Make sure you don't spray carb cleaner on the TPS or IACV connector and dry any cleaning fluid before putting the throttle body back in.

Also, was it the same mechanic who installed the timing belt incorrectly who did the repair again and is diagnosing this issue? If yes, you might want to try a different mechanic. From what you're saying it seems like you're just shooting in the dark. 

If your battery was disconnected during the repair, it might even be that your ECU was reset and is still re-learning. How many kilometres have you driven after the repair? Also, is the check engine light showing up on the dashboard? Did you for broken/loose/disconnected vacuum lines? Did you adjust the TPS at some point? Was the idle screw tampered with?

 

[Essien]

Thanks Davy

I really appreciate your concern and information its really helping. The truth is, I got the correct timing position online when I realize the mechanic had made the mistake. I discovered one of the spark plug coil was not contacting.

I have not driven the car for long distance because of the stalling issues and I also notice a high fuel consumption during test driving.so am planning on changing all the spark plugs and the faulty coil.

Please how do I reset my ECU when the vehicle is still stalling? the check engine light is on and it has been like that even before the problem. It was when I had issue with the tthrottle body then, that the check engine light was blinking,and its stoped when I replaced it.

[Davy]

  On 3/12/2018 at 10:07 PM, Essien said:

Thanks Davy

I really appreciate your concern and information its really helping. The truth is, I got the correct timing position online when I realize the mechanic had made the mistake. I discovered one of the spark plug coil was not contacting.

I have not driven the car for long distance because of the stalling issues and I also notice a high fuel consumption during test driving.so am planning on changing all the spark plugs and the faulty coil.

Please how do I reset my ECU when the vehicle is still stalling? the check engine light is on and it has been like that even before the problem. It was when I had issue with the tthrottle body then, that the check engine light was blinking,and its stoped when I replaced it.

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You should have mentioned that the check engine light is on. That's an important bit of information! 

Get a diagnostic scan done and address the error code(s) first. The ECU is already telling you what's wrong, so don't blindly replace stuff ignoring the check engine light.

You can perform a manual ECU reset by disconnecting the negative battery terminal, waiting about 15 minutes to allow for capacitor discharge and reconnect it. Your check engine light will re-appear after a while if the car still detects an issue. I recommend doing the diagnostic scan before resetting the ECU because you will lose all stored error information when you reset the ECU and an intermittent error might not resurface again when you want it to.

[Essien]

Thanks

I tried to reset the ecu by removing the negative terminal of the batery for some minutes, but it initialy appeared to be working but after like 10 seconds, the rpm goes down to almost zero and shaking then dies.the worse thing again is that the batery light as join the check engine light on display even when the car is moving .

[Davy]

  On 3/14/2018 at 12:34 PM, Essien said:

Thanks

I tried to reset the ecu by removing the negative terminal of the batery for some minutes, but it initialy appeared to be working but after like 10 seconds, the rpm goes down to almost zero and shaking then dies.the worse thing again is that the batery light as join the check engine light on display even when the car is moving .

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Again... You need to get a diagnostic scan done. There are clearly issues now that the Check Engine light is coming up even after an ECU reset.

As for the charging indicator, I'm pretty sure it's because you didn't tighten the negative battery terminal properly.

Just get it scanned. Please.