Chevrolet Optra

[SEchan]

Advance needed.engine check light on, send to ws. diagnosed w com, it show cam shaft sensor. Replaced
2days later, engine idle irregular.
Ws plug on com & say all good.
Suggest to change spark plus & battery. Replaced.
Timing belt changed 6mth ago when I bought it.
Got back the car, 1day later, engine idle worsen till car actually stalled when waiting at traffic light twice.
Back ws.
ECU, crank shaft sensor also replug w a 2nd unit, problem unsolved.
Ws suggest it's the throttle unit.
Any reliable ws with Chevrolet service experience preferred for recommend?
Can anyone pls advice me?

 

[sinistral]

Google search suggest faulty idle air control valve.

 

[seeseelooklook]

Could it be fuel pump problem? Or ignition coil?

change ignition coil first if trying to troubleshoot cos it’s cheaper.

not an expert in car problems but these are the 2 common problems with Contis.

 

[iduncheckmail]

Could it be fuel pump problem? Or ignition coil?

change ignition coil first if trying to troubleshoot cos it’s cheaper.

not an expert in car problems but these are the 2 common problems with Contis.

This car is ex-daewoo, made in S.Korea la. What conti .

 

[thomas00]

Better sell this car.

 

[seeseelooklook]

This car is ex-daewoo, made in S.Korea la. What conti .

LOL. I didn't say his ride is a conti.

I said the 2 problems I mentioned are common with contis which I encountered previously.

 

[myviowner]

Advance needed.engine check light on, send to ws. diagnosed w com, it show cam shaft sensor. Replaced
2days later, engine idle irregular.
Ws plug on com & say all good.
Suggest to change spark plus & battery. Replaced.
Timing belt changed 6mth ago when I bought it.
Got back the car, 1day later, engine idle worsen till car actually stalled when waiting at traffic light twice.
Back ws.
ECU, crank shaft sensor also replug w a 2nd unit, problem unsolved.
Ws suggest it's the throttle unit.
Any reliable ws with Chevrolet service experience preferred for recommend?
Can anyone pls advice me?

You can try R.D.Y Autocare at Ang mo kio. The boss of the shop drives a Chevrolet. His shops mainly deals with this brand of rides.

 

[tremor]

Why is this in hardware clinic?

 

[SEchan]

You can try R.D.Y Autocare at Ang mo kio. The boss of the shop drives a Chevrolet. His shops mainly deals with this brand of rides.

Many thanks for time to reply me this newbee.

 

[keenklee]

Advance needed.engine check light on, send to ws. diagnosed w com, it show cam shaft sensor. Replaced
2days later, engine idle irregular.
Ws plug on com & say all good.
Suggest to change spark plus & battery. Replaced.
Timing belt changed 6mth ago when I bought it.
Got back the car, 1day later, engine idle worsen till car actually stalled when waiting at traffic light twice.
Back ws.
ECU, crank shaft sensor also replug w a 2nd unit, problem unsolved.
Ws suggest it's the throttle unit.
Any reliable ws with Chevrolet service experience preferred for recommend?
Can anyone pls advice me?

IMHO and especially, IIRC.
P.S. There should be many variant of Optra. Below is for the FL which is the older model.
Not sure if it applies. If got idling issue, looks like similar.

The engine is not efficient ( runs dirty) because of the low compression ratio.
The exhaust by-product will reach the throttle body which will cause idling related issues.
The engine also runs hot which will wear/tear other components.

For idling related issues after service, repair or otherwise, you will need to perform the
IDLE LEARN PROCEDURE.

1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 5 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is
above 185° F (85°C ).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic transaxle,
apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is
complete

Source : https://www.fixya.com/cars/t17504350-idle_learn_procedure_2005_aveo

Some tips.
1. Do not use RON98
2. Use fuel with cleaners ( best is Caltex )
3. Every 5000km, use a bottle of Caltex Techron in the fuel tank
4. Buy and bring distilled water for coolant change.
5. Use a good quality 5w40 engine oil. Do not overfill the engine oil.
6. Change ATF every 40,000 km. Do not overfill the ATF.
7. Tyres - cannot use comfort tyres. Must use semi-performance ones that has stiffer side walls to complement the Lotus tuned suspension.

Common Issues
a. Engine cover gasket leaked. ( Due to engine oil )
b. Throttle body dirty ( Lack of maintenance and fuel used )
c. Radiator microscopic leaked ( Not using distilled water during timing belt change )
d. Erratic fuel gauge. ( Dirty )

By any chance you using Shell petrol ???

You can go R.D.Y Autocare. The above tips applies.

 

[keenklee]

I expand the idle learn procedure

The car must be driven for quite a while for the engine to reach the operating temperature.

1. Park the car. Engine off. Handbrake engaged. AC OFF. off.
2. Turn the key to ON. The ding ding ding will last about 5 seconds.
3. Turn the key to OFF.
4. Turn the key to ON again and wait for the ding ding ding to complete.
5. When the musical dings completes, turn the key further to start the engine.
6. Look at the digital clock.
7. When the digital clock minute moves by 1.
8. Turn the A/C to ON for 10 seconds.
9. Turn the A/C to OFF for 10 seconds.
10. Step brake, keep the brake depressed and change AT to Drive.
11. Turn A/C to ON for 10 seconds.
12. Turn A/C to OFF for 10 seconds.
13. Shift AT to Park
14. Turn off engine.

IIRC, when just move off and the engine dies, can shift to Neutral and crank start engine, shift back to D and continue .........

 

[yycools]

Have the ws check all the vacuum lines are connected properly, and if there are any possible air leakage. Poor idle/stalling can be caused by disconnected vacuum lines, or hoses leaking air. It might be an oversight by the ws