Difficulty Starting Engine and Uneven Idling

[Siewss]

I encountered a new problem upon reaching Port Dickson 2 days back:

 

1) Difficult to start - the engine normally just fires up at the turn of the ignition, but after parking for 1 hour at the resort carpark, the engine refused despite a few series of cranking. At the end, I got the car started after applying gas through the pedal. It's still the same today.

 

2) Idling is uneven - when in the past the engine will turn at 850rpm thereabouts (with or without aircon), now the rpm fluctuates between 700~1000, depending on the aircon. Vibration can also be pronouncely felt the cabin, when in the past such intrusions were completely absent.

 

Everything goes back to normal once on the run - no power loss, smooth pickup and cruising....till the next stop.

 

Thinking back, I can only relate this symptom to one thing I did wrongly. 2 weeks ago, the engine was idling quietly when I absent-mindedly cranked the engine. There was that all familiar sandy-rasping sound, but nothing happened at that point.

 

Anyone can advice what could have gone wrong?

[Kb27]

Idling valve problem

[Siewss]

Idling valve problem

 

That's a possibility. Is difficulty in starting the engine also linked to the idling valve?

 

My 1st thought was weak battery, but the cranking wasn't weak at all - it just refused to fire up.

 

My 2nd thought was sparkplug misfiring, and this seemed likely. I stood behind the exhuast pipes, and can hear the irregular spurt of emitting gas, unlike the usual low pitch throb I'm accustomed to.

 

I'll guess there's only one way to find out - send to the workshop.

 

 

[Macrosszero]

Maybe fuel pump issue also?

[Kb27]

That's a possibility. Is difficulty in starting the engine also linked to the idling valve?

 

My 1st thought was weak battery, but the cranking wasn't weak at all - it just refused to fire up.

 

My 2nd thought was sparkplug misfiring, and this seemed likely. I stood behind the exhuast pipes, and can hear the irregular spurt of emitting gas, unlike the usual low pitch throb I'm accustomed to.

 

I'll guess there's only one way to find out - send to the workshop.

You said you got the car started by "applying gas" then the engine started. What you've done is open the throttle plate so air can get in.

Without "applying gas" the only air passage is going into the idling valve, which is quite likely clogged based on your experience.

 

Then your idling is also unstable, which really points to a clogged valve.

[Mini-itx2010]

I encountered a new problem upon reaching Port Dickson 2 days back:

 

1) Difficult to start - the engine normally just fires up at the turn of the ignition, but after parking for 1 hour at the resort carpark, the engine refused despite a few series of cranking. At the end, I got the car started after applying gas through the pedal. It's still the same today.

 

2) Idling is uneven - when in the past the engine will turn at 850rpm thereabouts (with or without aircon), now the rpm fluctuates between 700~1000, depending on the aircon. Vibration can also be pronouncely felt the cabin, when in the past such intrusions were completely absent.

 

Everything goes back to normal once on the run - no power loss, smooth pickup and cruising....till the next stop.

 

Thinking back, I can only relate this symptom to one thing I did wrongly. 2 weeks ago, the engine was idling quietly when I absent-mindedly cranked the engine. There was that all familiar sandy-rasping sound, but nothing happened at that point.

 

Anyone can advice what could have gone wrong?

 

It sounds like your ICV is having problem.

[Yeobh]

One possibility is air bubbles in the fuel lines. The aeration maybe caused by very low fuel level in the tank or leaking fuel line fittings. Because of the presents of air bubbles, the fuel line header pressure is below the min require pressure ( most Asia car fuel header pressure is about 7kg/cm2) require for efficient firing - low pressure and low volume resulting in no firing.

Maybe it is good to have yr mech carried out check on the fuel line /injector pressure.

[Siewss]

Maybe fuel pump issue also?

 

I suppose anything to do with air/fuel intake is now suspect. I'm glad I made it home if it's really a fuel pump problem.

 

[Lowrider]

check all vacuum hoses for leak before inspecting something else...

 

hope u can solve the problem and nothing serious...

[Siewss]

You said you got the car started by "applying gas" then the engine started. What you've done is open the throttle plate so air can get in.

Without "applying gas" the only air passage is going into the idling valve, which is quite likely clogged based on your experience.

 

Then your idling is also unstable, which really points to a clogged valve.

Now that I'm back home, there's been a change in the symptom - now the engine fires up to 2krpm instantly before settling down to 1krpm after 5 secs. I don't need to prod the gas pedal to get the engine started.

 

But the idling problem remains - it swings from 900 rpm to 700 rpm at regular intervals, resulting in the characteristic vibration of low RPM.

 

I have a bottle of STP engine cleaner - wonder if that will help in clearing the clog, or need something more drastic.

[Siewss]

It sounds like your ICV is having problem.

 

 

Is ICV = idling valve?

 

I wonder if it can be resolved by pouring a bottle of those engine treatment solvents into the fuel tank, and let it run for 10 mins.....

[Siewss]

One possibility is air bubbles in the fuel lines. The aeration maybe caused by very low fuel level in the tank or leaking fuel line fittings. Because of the presents of air bubbles, the fuel line header pressure is below the min require pressure ( most Asia car fuel header pressure is about 7kg/cm2) require for efficient firing - low pressure and low volume resulting in no firing.

Maybe it is good to have yr mech carried out check on the fuel line /injector pressure.

 

Meaning there's a leak in the fuel lines?

 

Will this still be a possibility if I can drive 300km back from Port Dickson without a hitch? Problem only comes back when the engine is idling.

[Siewss]

check all vacuum hoses for leak before inspecting something else...

 

hope u can solve the problem and nothing serious...

 

Good idea. Check hoses before going on to idling valve.

 

Will swing by the workshop today if possible.

 

[XALmoN]

the iacv is easier to check than your hoses leh. check the iacv first.

[Kb27]

Now that I'm back home, there's been a change in the symptom - now the engine fires up to 2krpm instantly before settling down to 1krpm after 5 secs. I don't need to prod the gas pedal to get the engine started.

 

But the idling problem remains - it swings from 900 rpm to 700 rpm at regular intervals, resulting in the characteristic vibration of low RPM.

 

I have a bottle of STP engine cleaner - wonder if that will help in clearing the clog, or need something more drastic.

Most likely your idling valve or IACV is clogged.

Pouring STP engine cleaner to the oil sump will not help.

Need to remove the IACV to clean.

IACV is in the air passage, not the fuel or oil lines.

 

Just curious, are you using stock air filter or some "high-performance" air filter ?

Edited October 25, 2010 by Kb27

[XALmoN]

if you can still find carburettor cleaner, take out your air filter, spray some after the AFM, then reassemble everything, then start the car up, go for a drive, see if anything changes.

[Rainman]

I encountered a new problem upon reaching Port Dickson 2 days back:

 

1) Difficult to start - the engine normally just fires up at the turn of the ignition, but after parking for 1 hour at the resort carpark, the engine refused despite a few series of cranking. At the end, I got the car started after applying gas through the pedal. It's still the same today.

 

2) Idling is uneven - when in the past the engine will turn at 850rpm thereabouts (with or without aircon), now the rpm fluctuates between 700~1000, depending on the aircon. Vibration can also be pronouncely felt the cabin, when in the past such intrusions were completely absent.

 

Everything goes back to normal once on the run - no power loss, smooth pickup and cruising....till the next stop.

 

Thinking back, I can only relate this symptom to one thing I did wrongly. 2 weeks ago, the engine was idling quietly when I absent-mindedly cranked the engine. There was that all familiar sandy-rasping sound, but nothing happened at that point.

 

Anyone can advice what could have gone wrong?

 

Mine has the same idling problem too, but if I off the aircon totally, the problem is gone....

 

Think its time to service the aircon.

 

[XALmoN]

aircon compressor will definitely draw a load on the car, but maybe just do a regas and see how it goes?