Diagnosing a vacuum leak in intake manifold

A Malfunction indicator light (MIL)/Check engine light (CEL) indicated trouble with the EGR (Exhaust Gas Recirculation) in a Mazda Mx6 1993. Vacuum hoses, solenoids, EGR valve position sensor and the EGR valve itself were checked. Pretty much everything checked out, with the exception of a vacuum "nipple" source which upon application of external vacuum didn't hold vacuum nor 'sucked' with the car in idle (good vacuum should be produced with a closed throttle plate). Since the source of vacuum used for the EGR valve is 'stored' in vacuum chambers/vacuum reservoirs, a leak in their connections could explain the EGR malfunction code. Thus, here I performed a 'propane test' but using Throttle Body cleaner instead --Carb cleaner is supposed to be equivalent. Be careful, this is FLAMMABLE. Have somebody look at the RPMs in the tachometer while you spray carb cleaner in suspected areas (use a straw). In this case I started with UNO (1) at the firewall, driver's side of the air intake and proceeded clockwise in 10 total spots - the last 6 correspond to pits where spark boots enter the engine (intake runners). The flammable carb cleaner taken by a vacuum leak proceeds into the intake plenum enriching the gas:air mixture and increasing the engine speed, which is the readout here. I'm NOT responsible for any mishaps you might make. Actually I do NOT recommend this test, if at the end you do not want to spend the whole weekend disassembling or assembling the intake manifold (it's up to you).

Category:

Autos & Vehicles

Tags:

• Vacuum
• leak
• vacuum
• chamber
• reservoir
• intake
• manifold
• carb
• cleaner

[opsvideo2008]

Can you please advise whether I can use an aerosl contact cleaner instead of a carburettor cleaner? Its contents is petroleum distillates and it consists of hydrocarbons. 

[robueno70]

@opsvideo2008 I guess that if petroleum distills are what your solution is made of, yeah, go ahead and try it. Just be careful.

[turbomx66]

that is a MX-6 correct?

[robueno70]

@turbomx66 Correct, this is an Second generation Mazda MX-6 2 LS 2.5L V6. I was hit on the driver's side door, so it was considered a total loss. The car is gone now.

I do happen to have a brand new Mazda orignal tensioner+timing belt for sale.

[Jr72]

hey man you seems to know what your doing maybe you can help me?i got the same problem with my ranger 2004 the garage said there's a leak vacuum in the intake manifold.wich is due to (gasket plenum or another gasket) my neighbour just moved and the guy is a fucking junky.the guy put something in my gaz tank. unfortunartly a started my truck i did drove for a minutes and the gaz pump gived up and now a leak vaccum.any idea whath he can put that can cause that?

[robueno70]

@Jr72 Hey man. Possibly the guy added oil spirits to your gas tank. A few people have complained about adding these to an empty gas tank without filling up the tank immediately, which makes things worse for no known reason. Alternatively some junk from the tank clogged your fuel system. Check fuel pressures and possibly also change the fuel filter. Do so following the Haynes manual instructions for your vehicle. Failing to do so could be life threatening. Good luck.

[marc2583]

WTF is that a smile face light on the dash

[Morbidminister]

If you speak three languages your trilingual, if you speak two languages your bilingual, if you speak one language your American. Lazy ass Mercans.

[ThePsychoBrigade]

@opsvideo2008 i use strting fluid or brake clean

[biggurs]

also if you smell, and are a gay dad fucker then you definitely an american

[ericklgh]

Por lo que escucho hablas español, hablo ingles tambien pero no entiendo que es un vacuum leak... podrias explicarme que es y como encontrar el problema?

porque me pasa lo mismo con mi nissan sentra 2002, y no se como arreglar el problema

[zthundrbird]

Your all idiots..... got a gov that rips us an new ass every day and you HAVE to go after your brother man. Just a Joe Grunt like your self. Fucking brilliant. Doing thier work for them :/ Anyways' you chublets want to know how to track down a intake leak? Hoses etc? Get a can of quick start and spry it lightly in small qiuck bursts 1 area at a time. Wait a sec for a responce, engine will rev up when you hit a leak or crack in a hose. Just keep spray from intake hose, go figure, lol.

[Division1985]

@ParadiseofTruth Hey, that's exactly what happened to me last week, word for word. Yes, the hose sprung a leak, and I had it replaced. The check engine light went off, but came back on the next day, so I'm like wtf now..

[ParadiseofTruth]

When a vehicle has a vacuum hose leak, does it cause the car to vibrate violently when you get up to a certain speed? Also, when you come to a complete stop (red light, stop sign), does the car sometimes cut off? If that's not the cause of a vacuum hose leak, then what is? 

[lazyboy2oo6]

SES light wouldn't be on if you had a vaccum light... its prolly a loose connected AFM