Jeep Cherokee 4.0 vacuum leak solution

[@goldenresin5221]

I just looked and that is exactly what the problem is on mine. You saved me a lot of unneeded work!

[@TR-qr9hs]

What code was giving you. Mine running to lean wasting alot of gas.

[@richardweinberger2756]

My 2000 XJ had an intermittent high pitched whistle that would put the check engine light on. Yup, another bad rubber elbow, mine was the bigger one on the intake manifold that the A/C and cruise control feed off of. If it's a 20 year old car then we need to check ALL the rubber connections - they don't last forever.

[@kevinkibler2181]

I have that same whistle sound coming from mine.... I'm gonna look at that. Thanks buddy!!

[@jamesdoe5824]

Good video. These rubber elbow connectors are located all throughout the vacuum system so if you don’t find your leak here, check the other connections. Mine was at the connection going into the firewall as well as the connector going straight into the intake manifold. My air conditioning vents worked properly after I fixed it. There must still be a tiny leak left somewhere in my system because when accelerating, the vacuum system loses pressure. Anyone else experience this?

[@sotoman2]

Kaipo Fitisemanu Thanks! Have you tried smoking the vacuum system? It's a great way to find leaks.

[@jat-justamaturetech-philpj8285]

Which of the three hoses from the manifold was it to the firewall??✌

[@owenlittle9172]

Bro thank you so much! I think this might be my problem. It was like ear piercing on how high The whistle was

[@thomasdearment3214]

FYI the Grand Cherokee has those too, front of the throttle body black square box its underneath pointing down 90 degrees to the throttle body

[@wjb111]

Very interesting. Mine just started making that vacuum noise and haven’t been able to find it. You may have just solved my problem.

[@TheChosenOnex7]

Did you get a check engine light ?

[@wjb111]

@@TheChosenOnex7 Nope

[@cherylkirk7242]

Your idle air control will do that to.

[@cherylkirk7242]

@@TheChosenOnex7 your map sensor controls air in the intake

[@JoseReyes-wo2lm]

( I use a rubber hose, one end in my ear, I prob around, it magnifies the sound !)

[@shaimran8933]

ty bro

[@drew-shourd]

Cool video, thanx bro....ain't it always those damn elbows....and the butler, always dem elbows and butlers...hahahaha

[@cherylkirk7242]

You might think its a leak but its good possibility it is map sensor

[@8avexp]

On my '88, the tube going to the MAP sensor elbows into a rubber plug at the throttle body. That rubber plug popped loose just as the engine started; it almost sounded like a misfire. There was a loud hissing sound and the vacuum gauge dropped from 15 to 11 inches of mercury. After a minute or two of poking around, I spotted it. Plugged it back into the throttle body - problem solved.

[@sotoman2]

Replace it! Snug is not good. Rubber under the hood needs to be airtight. Snug is why the elbow popped off. Technically the elbow is a failed component. The rubber becomes brittle over time. Those are high temp and high pressure systems under the hood, snug is never airtight. When you put on a new elbow it should be difficult, like it's too small to fit. But use a little spot and it'll cooperate. It should be on there airtight and really tight. This is the only way that air won't get in or out.

[@8avexp]

@@sotoman2 Sadly, that Jeep is on its deathbed now. Cranks, but won't fire. It's not the crank sensor, either.

[@sotoman2]

@@8avexp no spark or fuel getting in there. If you have a spark tester use it on each plug wire and see if it sparks when you crank it. Narrow it down one thing at a time. You'll get it running.

[@nathanmccumber8965]

​@@sotoman2what code was it throwing ?

[@sotoman2]

@@nathanmccumber8965 It wasn't throwing any code. It wasn't bad enough to register on the OBD2 system. The OBD doesn't really register performance related issues. Think of it more like fine tuning.

[@jat-justamaturetech-philpj8285]

That elbow is too BIG! I just replaced my MAP last night. It's a bit of a bitch to put on cause it's so small and it's right under the sensor and you can't see to put it on, so I put some spit on it and it worked!🤣

[@kowalski363]

Great video

[@manualtuning5222]

I think I have the same issue, whenever I have the Jeep running it literally sounds like someone screaming "weeeeeee" really high pitched and I have code p0306

[@SuperBobby1974]

Where can I buy those elbows? Do you have part numbers?

[@luishuertag.6357]

Repuestos codos de vacío: Dorman 47431

[@jerroldtaylor3047]

Good to know will try

[@jesse4335]

I just got a check engine light and u can't find that elbow

[@allenfurtado9849]

did the whistle sound stop when accelerating?

[@allenfurtado9849]

I have found that a cracked exhaust manifold and cracked exhaust manifold gasket. That was the origin of my whistling when idle

[@joshuaderstine4133]

Fuel line clamps work also

[@sotoman2]

Clamps are a great idea.

[@jamesjohnson427]

Why so many beanos on these car links?

[@maniacalmonster2293]

SORRY FOR THE NOVEL You say what...? Vacuum leak its a loud whistle??? THATS what that is???? Man you say yours is bad...? I’m always having to work on my car late at night and when I start my engine the whistle is so loud I believe that I wake up my neighbors lol until my engine warms up and it goes down to almost nothing....Almost. Anyway, I tried to just diagnose the sound by ear where it was coming from and I swear it was coming directly from my alternator. This I’m thinking because my ear is within an inch of it and it sure as hell sounds like the whistle is coming directly from my alternator. So, I thought I needed a new alternator and was about to purchase one and replace it. So that maybe just saved me a wasted purchase and this vacuum leak is somewhere else or, can the alternator possibly cause a vacuum leak to make that whistle??

[@sotoman2]

Sorry I haven't been around to reply to everyone. But try this to isolate the cause of the loud sound you have: -1. get a large piece of metal, like a long screwdriver, or an extendable antenna from a radio, or any other long pole-like metal rod. 2. Start the car, and use the piece of metal like a doctor's stethoscope and touch all components under the hood (be careful!) The effect is like putting your ear to train tracks and hearing the train off in the distance. It does work. The cause of the sound will be much louder than the other parts.

[@StockCarGuy]

does this cause ac to not work properly as well ? also effects cruise control.

[@TR-qr9hs]

Did you figure out what wrong or your a/c.

[@StockCarGuy]

@@TR-qr9hspartly fixed, will be fixing up my jeep later this yr

[@jackrose5670]

A Throttle Body Spacer will cause a whistle at idle also.

[@dcarden3031]

Did you m.a.p sensor cause a lose of power

[@sotoman2]

D Carden Yes I did the map sensor.

[@jmeezy6342]

So you just felt around? I have a 97 with a vacuum leak, but I have very little mechanical knowledge.

[@sotoman2]

J Meezy Yes. I had the engine running, and I felt the different vacuum hoses. I.e. I squeezed them, or I covered them with a few fingers. Doing this could reveal a leak. Listen for a change in sound when you try the different hoses.

[@BUKWulfSh0t]

I just got code p1294 on my 97 xj I drove it around there block and now it won't start it cracks but no start... any idea?

[@BUKWulfSh0t]

I also replaced the 02 sensor with Walker brand.... can that be the issue?

[@sotoman2]

first- dont EVER clear your OBD codes! the computer scans and finds the problem. you fix it, then the computer scans and if the problem is fixed, the light goes away on its own. if you clear codes youre erasing the history of everything that the computer is keeping track of. okay it sounds like your air/fuel ratio is bad. since you reply to my video about vacuum leaks lets start with that. (since im not there to see it myself) if a vacuum leak is letting in too much unaccounted air, it can prevent it from starting. heres what you should do for starters: double check your battery voltage, replace every damn vacuum hose that you can! -- our naked eye cannot detect microscopic tears in a hose, nor can it tell a good hose from a worn out loose one. i was an army mechanic, Dod certified. trust me when i tell you that if it 'feels' good or if it 'feels' okay its probably not. ive seen it many many times when a vehicle has many tiny vacuum leaks, they add up. the guy thought it was his engine. do your car and yourself a favor. replace all the hoses one by one. your jeep deserves it. also never forget that we put our lives and the lives of our loved ones in our vehicles. dont go cheap, and dont cut corners. once you find the problem(S), your car will run better than ever!

[@twilliamsusmc]

I really wish my vacuum leak was more major.

[@joethenerd2427]

Just give it some time 😂

[@ralphnabozny8494]

Thank you. I have been smelling fumes. Thanks. I completely missed that. I was going to sell the car. But I love my car. I will look thanks to you. real hard. did it smell funny?

[@sotoman2]

It can. Depends on where the vacuum leak is

[@justinflowers2111]

This reply is late, but I believe if you are smelling fumes, it would be a good idea to check the vacuum lines and elbows connected to the fuel evap canister. The elbow leading from the canister to the fuel tank was badly cracked on mine, (even though I was not smelling fumes).

[@nathanmccumber8965]

What codes were you getting ? And are u by Midwest are u selling xj ?

[@spokes1355]

I have a 98 that I just changed the intake and manifold gasket on and. Now when i crank it it goes to about 5,000 rpms high rev like someone is holding the vas pedal down

[@sotoman2]

Altin Wood Sounds like the idle air control valve. It's on the throttle body. Take it off, clean it with carb cleaner, see if it helps. Let me know what happens!

[@antigen4]

i had the same thing as Altin Wood but i replaced the IAC and a few other sensors - NO DIFFERENCE - so the hunt continues

[@kylequatier4408]

Check the Pcv elbows on top of the valve cover

[@patrickmoehle3763]

I came across this issue on a 4.0 Person had replaced intake manifold gasket.. Problem was when putting the manifold back on didn't get manifold lined up with pins on the head so manifold did not seat to the head completely. Engine was puling in air between manifold & head. So much air it would it would burst to 4500 rpm. Took manifold back off lined up to the pins to seat manifold to the head & that solved the problem

[@talldave7799]

where can I find the vacuum lines to replace the one that's used for the Heater!?!

[@nathanmccumber8965]

U gotta flush it water hose it by fire wall.

[@nathanmccumber8965]

Or u gotta open Manuel Ally open door from passenger seat under glovebox by floor

[@awakenedgoddess2855]

Mines doing same thing man. Real bad. Tell me how u fixed it please. Driving me crazy

[@cynthiarichards6494]

Can you please let me know exactly what size is used for the vacuum elbow. I bought the one specific for the 2001 Jeep Cherokee and it doesn't fit.

[@sotoman2]

It fits! It needs to be an airtight seal! Use a little spit. It'll get on there. It feels like it's too small because if it's any less tight, air WILL get past it either in or out.

[@antigen4]

i have a 4.0 that starts slowly revving up to infinity (well i shut it off when i hit 3000 or so RPM) at idle after it starts getting warm . someone on a forum suggested to me that it might be a vacuum leak ... does this make sense? I tried checking a few of the relevant sensors and even replaced a few but that did nothing .. any advice would be appreciated.

[@sotoman2]

Hi. Have you checked out the throttle position sensor and the idle air control valve?

[@antigen4]

yes cleaned and replaced both ... thinking now it's either my head gasket or else computer needs to be reset from a low voltage condition previously

[@sotoman2]

@@antigen4 Double check for vacuum leaks with smoke. An old fog machine works best. I'd start there instead of the computer

[@antigen4]

i think the computer would be the easiest to try first - no effort required - someone with almost my exact complaint on a forum has this problem and it was solved by resetting the computer - weirdly enough - so i figured it's worth a try ... but since the behaviour only starts after about five minutes when the engine is good and hot - i suspect either the head gasket of exhaust manifold ... certainly could be a random vacuum line though - as long as it's attached to something large and metal which expands when it gets hot ... i guess ... though i would maybe try the WD40 thing before the smoke trick

[@antigen4]

as for the head gasket - i was thinking along those lines since a head replacement was the last thing that happened to the engine ...

[@slyjeeper]

🤙🏼wave