How To Find A Vacuum Leak - EricTheCarGuy

greetings fellow gearheads or in some parts of the world petrol heads eric the car guy here i get lots of questions about performance issues and something that i recommend to check for a lot of times is vacuum leaks but i'm never quite clear on how you check for them and for me being clear is making a video about how to check for them now there are a couple of different ways you could do this there's the correct way and the correct way involves using propane enrichment which you would take a piece of fuel line and cut the end of this torch off or find an end that you could fit this hose on to and crack crack it open and go around the suspected area of the vacuum leak looking for an idle change this is actually safer than the method that I'm about to show you which is using carburetor cleaner most common method is carburetor cleaner but a word of caution and I've seen this firsthand especially when the engine is hot there is a very high potential to catch it on fire and if you do that that would make for kind of a bad day so should you employ this method that I'm about to show you I insist that you have a fire extinguisher handy and one that's fully charged if not you run the risk of burning your car down so definitely take that into consideration also if you do this with the engine cold you're much better off a vacuum leak creates a lean condition and many times what the car will do to compensate it was that will richen up the mixture now some vacuum leaks you can hear I've got a pretty good ear for vacuum leaks not four beeps of keys but a pretty good hear from vacuum leaks so when I hear that high-pitched hissing noise the first thing I look for is a vacuum leak particularly if there's a performance problem or if you get into more advanced diagnostics like say for instance you're looking at Short and long term fuel trim on a scanner you'll notice that it goes rich so if you see something that trends rich it may not be the o2 sensor that you're looking at it may very well be a vacuum leak in fact that's the first thing that I would look for let's get to it just to note that whether you're using carburetor cleaner like I'm using here or you're using propane the same rule applies you spray or hold the propane in the suspected area of the vacuum link and you listen for engine idle to change first you've got to start the engine now generally where I like to look is around the intake manifold for leaks because basically that's where intake manifold starts an end is all around the intake manifold area don't forget to spray around PCV valves things like that but basically what you're doing is you just spray like around with a base of the injector power anyplace they're vacuum when I connect there's one there notice the change in the engine right here I can't even stall the engine on this one that shouldn't happen let's do it one more time stop in the complaint on this car was that it would stall intermittently but start right back up kind of a strange problem to diagnose sometimes because well it's really difficult to diagnose something that's not acting up so in this case I'm just looking for everything and keep an ear out for that high-pitched noise I don't know if you could hear it on camera or not but if you hear that high-pitched noise while your engine is running and you do this test and you can stall the engine that's how you find an intake leak once you've found the intake leak repair it it may take some time for the ECU reset or you may or you may want to reset the ECU because what will happen with that short and long term fuel trim which I'll get into in another video is the engine will be biased rich so it will compensate for the extra air coming in through the vacuum leak and once you get rid of the vacuum leak it's all messed up it wants to make it richer than it was before so may well not want to run right for a while until it acclimates or if you reset the ECU it may be okay so that's how I check for vacuum leaks once again word of caution on a hot engine this can cause a fire so be very careful of that and have a fire extinguisher handy if it catches on fire and don't panic just grab the fire extinguisher and put it out if you don't have a fire extinguisher it's a bad day fire extinguishers make a big mess but you'd be surprised how much doesn't burn the engine is used to getting a lot of heat so even if it looks like the end of the world you put those things out and I've seen this firsthand put those fires out first hand you got a lot of black stuff everywhere but most of the time things are still intact can't speak for your particular situation I just want you to be cautious i'm eric the car guy visit me at eric the car guy calm because it's so much fun and it's a really cool place to be oh yeah stay dirty see

Channel: EricTheCarGuy

Views: 5,516,003

Keywords: idle problem, won't idle, rough idle, stalls, idle, idle problems, bad idle, car won't idle, truck won't idle, vacuum leak, intake leak, finding intake leak, intake vacuum, intake vacuum leak, how to car repair, how to, how to repair, diagnosis, automotive diagnosis, engine diagnosis, performance, performance problem, truck repair, engine repair, engine, rough engine, diy, diy car repair, diy auto repair, automotive education, ericthecarguy, eric the car guy, etcg

Id: 9CPqbaSgcok

Length: 5min 56sec (356 seconds)

Published: Mon Aug 23 2010