Engine Light/Hissing Noise When Pressing Gas - 2001 Hyundai Sante Fe

GET OUT QUICKLY! IT MAY BE POISENIOUS SNAKE!

GA from me.

He should also search for the (sir?) hiss with the AC belt removed (AC electric clutch disengaged may not be an option on all cars) to see if the hissing then stops completely.....

But if it was the AC, the AC would be "empty" in a very short space of time and:-

a) you could have smelt the filling and

b) the AC would stop working/compressor damage.

Its most likely a vacuum leak (and its a petrol engine which develops a vacuum normally) on the intake manifold. Some cars use vacuum to operate the heater controls etc...

You don't state if the hissing is coming from inside or outside the cabin. I will assume it is coming from inside as a large enough vacuum leak in the engine compartment to be heard inside the cabin would result in the check engine light coming on.

That having been said, have you checked the HVAC controls under the dash board area? Some of these controls may be (regulated low volume) vacuum assisted which would not necessarily trigger the check engine light.

Good Luck!

Thank you! The sound is coming from outside the cabin....I hope it will be an easy fix.

Thanks again!

You might consider kramarat's suggestion about using a hose. Seems that would make the leak easier to pin point.

Good Luck

Your exhaust is blocked

most likely the CAT

Its not vacuum as the vacuum on a gasoline engine all disappears when you open the throttle

the only thing that increases is the amount of gases going out of the exhaust

(I claim this statement as my own) " private joke"

this link is not mine.

http://www.youtube.com/watch?v=IzyvL5tQLzU&feature=player_embedded#!

this link is not mine either Hissing cars

http://www.youtube.com/results?search_query=car+makes+hissing+noise+&aq=f

HI I have just been looking at a web site run by an American called scottykilmer.com he was showing a gadget you could probaby use to locate you hissing noise, it is called Marksman, it works by ultrasonic, try bringing it up on the web.

A further check on the web shows you can purchase the Marksman diagnostic tool from Amazon.com also www,spectroline.com

Guest,

In any case please let us know what you find.

Some good explanations/suggestions have been offered here.

I am very curious now.

Thanks - KJK

If you can find the throttle body, you should be able to find the vacuum leak, if it is only leaking when on the throttle. the throttle body is what the throttle cable is connected to. Any vacuum leak that is only present when on the throttle will have to be from a vacuum hose that is just above the throttle plate in the throttle body. Examine any hose connected above the throttle plate, and you should be able to find your leak. Good luck.

Check for leaks in the Air Box/Air filter or air inlet from filter to throttle body.

I have an Aussie car with LPG conversion. The engine backfired up through the inlet (a not uncommon thing on LPG motors if things are not set correctly) and actually split the air box (that holds the filter). Waiting on replacement airbox, however the enginge does exactlky as you describe - hisses under open throttle. Its not exactly manifold vacuum, (agree with PeterG that manifold vacuum drops when throttle is open) its the low pressure caused by the restriction of the air filter, & the air gets sucked in through the cracked airbox when you push the throttle down a reasonable amount.

BTW My Engine Warning light is not on.

Tony

If the check engine light is on again, then you might want to have a different mechanic check the codes. It seems likely that there could be a connection between your noise and a monitored condition. Let us know what the codes are.

AC belt slipping?

My guess would be a plugged Cat with a small leak in the exhaust pipe in front of the Cat. Because of this the O2 sensor is sending an error message to the computer. Good luck.

Josh

Took my car to AUTOZONE to get print out of Engine Light codes....came up with P0171 and P0174. Oxygen sensor(s) in bank one and bank two, was told had a rich Air/Fuel ratio. Also, sprayed belts with WD40 to help with the hissing/winding noise.

Now, what will the mechanic tell me to do?? Any suggestions?? I want to be prepared when I go into the repair shop and they tell me it is no big deal....that is what I have been told.

P0171 and P0174 mean a lean air fuel ratio, not rich. A vacuum leak is one likely cause. Here's some info on Fords, but the principals are the same. If you can get the car to make the hissing sound, a friend could help locate the cause, by listening with a tube, etc.

One of the replies suggests it might be the CAT. I had a similar sound - more a whoosh than a hiss - on a turbo diesel. It turned out to be the CAT. The primary CAT broke up and destoyed the secondary CAT. It was accompanied by significant loss of power (possibly because it was a turbo). The exhaust was forcing its way through the exhaust coupling as it could not go anywhere else.

Warning - If you are checking the exhaust do not do it in a closed space as the exhaust fumes can cause you to lose consciousness without realising it with fatal results. Better have someone around to check you are OK even in a well ventilated area.

You don't mention if the hissing noise started before or after the A/C was replaced? If the problem occurred after this, take it back to the A/C shop.