air sucking noise

BowtechAndy · 05-18-2007, 06:43 PM

99 ram 4X4 with a 5.9L V8. Its making a vacuum leak noise but nothing is leaking. Its not all the time either. any help would be great.

also, I am getting average of 13 miles to the gallon. I am lifting and going with bigger tires. Would you suggest reprogramming the computer with a hypertech? Is it worth the $350?

thanks

andy

75K30 · 05-18-2007, 07:05 PM

Welcome to the site.
If you have a vacuum leak sound, then it has to be leaking. How do you know it is not?
As for the reprogram, what are you hoping to achieve by reprogramming?
Since you mentioned gas mileage, I am confident that after you increase the tire diameter, and increase rolling resistance, a computer re flash, or reprogram will not provide any better mileage. You might get back to a similar mileage if you change the gears but don't expect magic from a programmer.

BowtechAndy · 05-18-2007, 09:20 PM

Because I have traced every line and can't find any leaks. The only one it might be is the big one right under the air breather cause its kinda loose fitting.

As for tires I will be using 285/75/16 which is basically a 33. After reprogramming to the larger sized tire it should still improve over what I am getting now. I hope!!!

75K30 · 05-18-2007, 09:35 PM

what did you do other than visually inspect he lines to verify they were not leaking? Have you tried introducing a chemical, either liquid, or gas to verify no leaks? Bet if you run some propane around with a small hose, you will find the leak. Works every time.

BowtechAndy · 05-18-2007, 09:49 PM

how is that done?

75K30 · 05-18-2007, 10:06 PM

Some guys use something like brake cleaner, or carb cleaner, to detect vacuum leaks. If you spray a little around a suspected area, the engine rpm will change. Once a change in idle is detected, you have found your vacuum leak.
The other method is to use a gas like propane, or similar gas, (combustable gas, inert gases will not work). I use the gas method because with the help of a smalll wand that I made, I can concentrate the gas on a smaller more acute area. The results are the same.
The gas method is a little safer (more safe?) than the carb cleaner. Carb cleaner has been known to catch on fire every now and then if sprayed on a dist cap, coil or something like that. Although it will also tell you if you have a spark plug wire that is arching somewhere, it is still a little dangerous to say the least.

BowtechAndy · 05-18-2007, 10:10 PM

so just squirt a little on a hose to see if it leaks? Thats sounds waaaaay to simple. Can you think of a harder way!!!!!!

75K30 · 05-18-2007, 10:56 PM

Spray on one hose, and listen for the engine rpm to change. The change in rpm will indicate a leak that is otherwise invisible to the eye.
But, if you want it a little more difficult, leave the hood closed, (LOL) that should make things a little more difficult for you...........

BowtechAndy · 05-19-2007, 05:22 AM

hahaha good one!!!!

BowtechAndy · 05-19-2007, 11:20 AM

tried using the spray on all the lines except the one under tha air breather just because I couldn't reach it. Noting changed so I am thinking that its either that hose or its just a noise that the intake makes.

Gonna try something else on a day its not raining.
thanks

andy

05-18-2007, 06:43 PM	#1
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	air sucking noise 99 ram 4X4 with a 5.9L V8. Its making a vacuum leak noise but nothing is leaking. Its not all the time either. any help would be great. also, I am getting average of 13 miles to the gallon. I am lifting and going with bigger tires. Would you suggest reprogramming the computer with a hypertech? Is it worth the $350? thanks andy

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05-18-2007, 07:05 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Welcome to the site. If you have a vacuum leak sound, then it has to be leaking. How do you know it is not? As for the reprogram, what are you hoping to achieve by reprogramming? Since you mentioned gas mileage, I am confident that after you increase the tire diameter, and increase rolling resistance, a computer re flash, or reprogram will not provide any better mileage. You might get back to a similar mileage if you change the gears but don't expect magic from a programmer.

05-18-2007, 09:20 PM	#3
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	Because I have traced every line and can't find any leaks. The only one it might be is the big one right under the air breather cause its kinda loose fitting. As for tires I will be using 285/75/16 which is basically a 33. After reprogramming to the larger sized tire it should still improve over what I am getting now. I hope!!!

05-18-2007, 09:35 PM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	what did you do other than visually inspect he lines to verify they were not leaking? Have you tried introducing a chemical, either liquid, or gas to verify no leaks? Bet if you run some propane around with a small hose, you will find the leak. Works every time.

05-18-2007, 09:49 PM	#5
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	how is that done?

05-18-2007, 10:06 PM	#6
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Some guys use something like brake cleaner, or carb cleaner, to detect vacuum leaks. If you spray a little around a suspected area, the engine rpm will change. Once a change in idle is detected, you have found your vacuum leak. The other method is to use a gas like propane, or similar gas, (combustable gas, inert gases will not work). I use the gas method because with the help of a smalll wand that I made, I can concentrate the gas on a smaller more acute area. The results are the same. The gas method is a little safer (more safe?) than the carb cleaner. Carb cleaner has been known to catch on fire every now and then if sprayed on a dist cap, coil or something like that. Although it will also tell you if you have a spark plug wire that is arching somewhere, it is still a little dangerous to say the least.

05-18-2007, 10:10 PM	#7
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	so just squirt a little on a hose to see if it leaks? Thats sounds waaaaay to simple. Can you think of a harder way!!!!!!

05-18-2007, 10:56 PM	#8
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Spray on one hose, and listen for the engine rpm to change. The change in rpm will indicate a leak that is otherwise invisible to the eye. But, if you want it a little more difficult, leave the hood closed, (LOL) that should make things a little more difficult for you...........

05-19-2007, 05:22 AM	#9
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	hahaha good one!!!!

05-19-2007, 11:20 AM	#10
BowtechAndy Senior Member Join Date: May 2007 Location: Maine Posts: 66	tried using the spray on all the lines except the one under tha air breather just because I couldn't reach it. Noting changed so I am thinking that its either that hose or its just a noise that the intake makes. Gonna try something else on a day its not raining. thanks andy