loss of power and black smoke when trying to accelerate (anti-shudder flap closes while driving)

**taxo_p** · December 26th, 2017 03:13 PM

Has anyone here experienced the same problem? I have a 2005 kia sorento crdi with manual transmission that very infrequently (about once every few months) would have a grinding sound coming from the front passenger side of the engine bay. Whenever this happens, the car would lose pulling power and black smoke would come out of the exhaust if I stepped harder on the accelerator pedal. The problem would disappear after I turn off and restart the engine. At first I thought it was the turbocharger that was malfunctioning leading to a pretty expensive "repair" that turned out to be unnecessary as I was able to finally confirm yesterday.

While I was driving, I suddenly heard the grinding sound (like a stuck electric motor) and then felt the loss of power. I stepped harder on the accelerator to see if black smoke would come out. It did and so confirmed to me that the problem was still there despite the turbo cleaning and rebuild.

I parked the vehicle in a nearby gas station and opened the engine bay while the engine was running. This was the third time it happened since the turbo cleaning and rebuild so I already had a suspicion it had something to do with the anti-shudder flap and the solenoid valve that controlled its function. This was however the first time it happened where I had the opportunity to park somewhere safe to look at the engine bay. As the engine was still running, I checked on the anti-shudder flap and saw that it was in the closed position. The grinding sound also seems to be coming from the solenoid valve that switches the flap to close.

I have been searching through different internet forums but can't find anyone reporting the exact problem. For now, I decided to just unplug the electrical connection to the solenoid to disable the anti-shudder valve function. If my understanding is correct, the anti-shudder valve is only used during engine shut-off to reduce the shudder and in cases of a "runaway diesel engine" scenario.
The electrical contact points look clean and free from corrosion. It seems to work fine during engine shut-off as I see it closing when I turn the key to off and open again after the engine has shut down.

Here are my options currently:
1. Keep the solenoid disabled(unplugged) as it does not seem to cause any adverse effects.
2. Replace the solenoid and see if it permanently solves the problem.

I'm leaning towards option #2 but would like to hear from others who may have better ideas. Can the solenoid be serviced with a simple DIY procedure? Any thoughts? Thanks!

**mda** · December 26th, 2017 03:17 PM

Don't know if you can repair it, but I think you should go for option 2 if yan nga yung problema. That thing is probably there for a reason.

While searching for the part, may as well observe the car to see if the problem returns just to make sure that the solenoid valve is really the problem.

**travajante** · December 26th, 2017 06:51 PM

Originally Posted by taxo_p

Has anyone here experienced the same problem? I have a 2005 kia sorento crdi with manual transmission that very infrequently (about once every few months) would have a grinding sound coming from the front passenger side of the engine bay. Whenever this happens, the car would lose pulling power and black smoke would come out of the exhaust if I stepped harder on the accelerator pedal. The problem would disappear after I turn off and restart the engine. At first I thought it was the turbocharger that was malfunctioning leading to a pretty expensive "repair" that turned out to be unnecessary as I was able to finally confirm yesterday.

While I was driving, I suddenly heard the grinding sound (like a stuck electric motor) and then felt the loss of power. I stepped harder on the accelerator to see if black smoke would come out. It did and so confirmed to me that the problem was still there despite the turbo cleaning and rebuild.

I parked the vehicle in a nearby gas station and opened the engine bay while the engine was running. This was the third time it happened since the turbo cleaning and rebuild so I already had a suspicion it had something to do with the anti-shudder flap and the solenoid valve that controlled its function. This was however the first time it happened where I had the opportunity to park somewhere safe to look at the engine bay. As the engine was still running, I checked on the anti-shudder flap and saw that it was in the closed position. The grinding sound also seems to be coming from the solenoid valve that switches the flap to close.

I have been searching through different internet forums but can't find anyone reporting the exact problem. For now, I decided to just unplug the electrical connection to the solenoid to disable the anti-shudder valve function. If my understanding is correct, the anti-shudder valve is only used during engine shut-off to reduce the shudder and in cases of a "runaway diesel engine" scenario.
The electrical contact points look clean and free from corrosion. It seems to work fine during engine shut-off as I see it closing when I turn the key to off and open again after the engine has shut down.

Here are my options currently:
1. Keep the solenoid disabled(unplugged) as it does not seem to cause any adverse effects.
2. Replace the solenoid and see if it permanently solves the problem.

I'm leaning towards option #2 but would like to hear from others who may have better ideas. Can the solenoid be serviced with a simple DIY procedure? Any thoughts? Thanks!

You seem to be running rich & struggling. Check your intake filter. I bet it's filthy & clogged. Change it.