Engine light, engine running lean

[Juddog]

To make a long story short, engine light popped on. I did a quick check online of what it indicates, engine code explanation states engine running lean. Looked around some more and it was said that it usually indicates a leak in the air intake system somewhere. So I pop open the hood, and I can hear the "HISSSSSS" sound, but for the life of me cannot find it.

Is there an easy way to find where the sound is coming from, or is it better to take apart the whole air intake system and put it back together piece by piece?

 

[programmer]

See if a long cardboard tube can help you isolate the sound (like from a tube of wrapping paper). Some hiss is normal, but yeah, with the light it probably means a vacuum hose fell off or cracked/disintegrated. You might also give a gentle tug to each small rubber hose and try to make sure both ends are connected properly. Good luck. Its probably a pretty easy fix.

 

[bruceb]

Sounds like a Vacuum Leak .. start by checking all the hoses for any that may have come off or feel loose on the fittings. Also any that are very old and maybe cracked should be suspected.

 

[Demon-Xanth]

Look for ends that are cracked, that happened on mine for a while (got it before the CEL) until I replaced a brittle hose.

 

[Juddog]

Originally posted by: Demon-Xanth
Look for ends that are cracked, that happened on mine for a while (got it before the CEL) until I replaced a brittle hose.

Ahh ok cool thanks for the advice everybody. I was looking at all of the connectors today for about a half hour and couldn't see anything that was loose, I didn't think to pull off the ends themselves and check for cracks.

 

[BW86]

Sounds like a vacuum leak - get a propane torch and attach a long rubber hose to the end of the torch. Turn the torch valve on and move the hose around the suspected leaking area. When your idle rises, you have found the leak.

If you think that sounds a little dangerous for you, you could always take a section of tubing, put one end to your ear, take the other end and point it at places around the engine. The tube acts like a doctor's stethoscope, and magnifies the leak sound when you get close to it.

 

[AdamK47]

This may sound weird, but take a cardboard center from a paper towel roll and put it to your ear. Listen around under the hood of the car. I've found an air leak from a hole in a hose on my Z28 this way.

 

[Belldo]

At my shop we take a can of carburetor cleaner and spray it on the vacuum lines and around the intake manifold gasket while the vehicle is running. When you find the leak you will notice the idle of the vehicle change

 

[Juddog]

Originally posted by: BW86
Sounds like a vacuum leak - get a propane torch and attach a long rubber hose to the end of the torch. Turn the torch valve on and move the hose around the suspected leaking area. When your idle rises, you have found the leak.

If you think that sounds a little dangerous for you, you could always take a section of tubing, put one end to your ear, take the other end and point it at places around the engine. The tube acts like a doctor's stethoscope, and magnifies the leak sound when you get close to it.

Hmmm interesting idea, I will try this when I get home. I have a butane blowtorch, will this work the same way?

 

[iamwiz82]

Originally posted by: Belldo
At my shop we take a can of carburetor cleaner and spray it on the vacuum lines and around the intake manifold gasket while the vehicle is running. When you find the leak you will notice the idle of the vehicle change

This is the method I used, as well. Worked for me.

 

[BW86]

Originally posted by: Juddog

Originally posted by: BW86
Sounds like a vacuum leak - get a propane torch and attach a long rubber hose to the end of the torch. Turn the torch valve on and move the hose around the suspected leaking area. When your idle rises, you have found the leak.

If you think that sounds a little dangerous for you, you could always take a section of tubing, put one end to your ear, take the other end and point it at places around the engine. The tube acts like a doctor's stethoscope, and magnifies the leak sound when you get close to it.

Hmmm interesting idea, I will try this when I get home. I have a butane blowtorch, will this work the same way?

yes

 

[Elstupido]

Just a tip, don't light the torch. Hope that helps. 🙂