Find Your Vacuum Leaks (FM Live)

[@b2bb]

MAJOR shade to the Subaru owners lmaoooo

[@AT-fi9dj]

Great lecture! Reminds me of auto mechanic school. An easy way to understand vacuum is to compare a piston inside a cylinder to a syringe. When you pull the plunger down in a syringe it sucks air in. Also, when a piston moves down in a cylinder it creates a vacuum and sucks air in. Many systems in the car use the vacuum generated by the engine such as the brake booster. When having this conversation you also need to discuss the oxygen sensor. That’s the sensor(s) in the exhaust that monitors what the air fuel ratio is. Ideally it should be the stoichiometric ratio of 14.7:1 (air:fuel). The car varies this ratio between lean and rich in order to allow the catalytic converter to do its job and clean the exhaust gases. When the O2 sensor reads too much oxygen, due to a leak in the intake, it will trigger a lean code.

[@sonofdescent3234]

Damn I thought that stumble my 94 is making was because of a bad fuel injector wiring harness. Going to check for a vacuum leak 😅

[@sonofdescent3234]

Update: it was the wiring harness 😅

[@michaelh.9866]

I've got a buddy that's a heavy smoker. Could I just get him to exhale into the tubing?

[@johannagnarsson]

What is the normal idle vacuum range for NB2 cars running your CARB Legal Turbo kit?

[@markfelkey1720]

How do you troubleshoot a brake booster internal vacuum leak and what are the symptoms of that kind of leak? (note this question was posted on your Instagram announcement of this live FM session beforehand.

[@FlyinMiataVideo]

We're sorry if we missed this one. Going back, I do not see this specific question on any of the instagram posts announcing this video. We try to stay on topic and only answer questions that are relevant to the video topic, and since this video was specifically for engine vacuum leaks, brakes were off topic and not addressed. If you need help with your brakes, please contact our support team directly. You can give us a call at 970-464-5600 M-F 8-5 Mountain time or drop them a line at [e-mail]. Thanks!

[@uncleansanchez]

Mark, I have the same question. I'm not sure how they consider it "outside the topic" when the brake booster is vacuum operated, but whatever. I currently have an all original '08 NC1 with 34k miles and its throwing a P0507 code occasionally and it idles up when I press the brake pedal. What are your symptoms like?

[@mr.lostmyaccount4721]

Could a vacuum leak cause an engine when idle to rev up from about 850 to around 1500rpm for a few seconds then back to normal?

[@FlyinMiataVideo]

Vacuum leaks can cause all sorts of erratic idle issues. If you need help finding the issue, give our customer support team a call. They'll be happy to try and help.

[@QuincyStick]

could be a vacuum leak, could also just be your idle is set wrong. the NAs have 2 different idles, one is mechanical and the other is ran by the ecu. when your car is idling the ecu takes a second to kick in so it relies on the mechanical one until the ecu catches up, hence why the erratic idle is only temporary.

[@BigStreams_]

Could a vacuum leak cause a slight fuel smell to be noticeable on start up?

[@FlyinMiataVideo]

Depending on the car, that smell is probably caused by either a faulty/damaged charcoal canister, bad injector o-rings, or the check valve near the fuel pump in the cabin. Please reach out to our customer support department directly for more info or help diagnosing your issue. Thanks!

[@dennisloh2250]

Could it be a vacuum leak or if not, what may be a cause of low rpm (1st/2nd)

[@FlyinMiataVideo]

This one might take some additional troubleshooting. Send us an email at [e-mail] or give us a call at 970-464-5600 so we can help!

[@darkrage1138]

Would jerry rigging a halloween fog machine with a hose, but using it instead of a smoke machine be okay? I feel like the answer is no, due to fog machines being water based.

[@FlyinMiataVideo]

It looks like most fog machines for parties use pretty similar stuff as the automotive machines, though we can't guarantee this! (use at your own risk). I'd aim for stuff that doesn't leave residue and is water-based. Be sure to leave the intake open to dry out for a few minutes before putting it back together.

[@rykaphotomedia]

Can it cause pinging at certain rpm and sputter when trying to downshift?

[@blackhatch46]

Hahahahaha all new stis come with a vape. Prove me wrong!

[@38tech]

Ok...need help trying to diagnose something. Cold start the car will stutter up to about 3500 rpm, as the car warms tje stutter hoes lower and lower till it just goes away completely as it reaches operating temperature. Any ideas??? Ive done the usual stiff like you just did and it yielded nothing Nb2 with 85k on the clock, all oem except a drop in k&n filter. Thanks in advance.

[@FlyinMiataVideo]

Would you mind reaching out to our customer support team directly for help with this? This could be a rabbit hole, and it would be much easier to diagnose with more information through a conversation rather than KZbin comments. Please give us a call at 970-464-5600 M-F Mountain time, or drop us an email at [e-mail]. Thanks!

[@Tethys213]

Mike's face at 24:03

[@Vtertdfgwrth5ybdfasgagadfg]

I know its a long shot but you have replied to me before hahaha, I have an nb and have been chasing an egr gremlin during which i discovered the vaccum hose coming from the hitachi "boost" sensor had been cut and removed, saw 2 other cars on the forms who have noticed this too, but no definitive answer as to why, do you guys have any info/ come across this before?

[@FlyinMiataVideo]

Cut and removed at the factory, or by a previous owner? That sounds like the sort of bad information that comes out of forums and facebook, that removing the boost sensor will (unlock more power/fix a certain driveability problem/increase sex appeal) especially if it's cross-pollinated from something like the MSM. Put it back, your gremlins will likely be reduced.

[@Vtertdfgwrth5ybdfasgagadfg]

@@FlyinMiataVideo Not sure, if it was from factory I would expect it to be capped off properly, may have been done by a previous owner. I will find some hose, fingers crossed😄👍

[@Evansforrest]

I didn’t see videos on doing a smoke test and purchased a vacuum pressure gauge. Can I use that to test I take and exhaust

[@FlyinMiataVideo]

It's easiest to pinpoint leaks when you pressurize the intake system so, that's why we suggest the smoke machine. Getting a vacuum reading can show a general leak but narrowing down the possibilities of where it's at will be difficult.

[@Evansforrest]

@@FlyinMiataVideo thank you, that’s clear. Question, do you see a loss of power from clogged fuel injectors? This symptom started suddenly, car starting fine, but lacking power, can’t get over 3500 rpm.

[@Evansforrest]

@@FlyinMiataVideo since I have a vacuum gauge and no smoke machine at the moment, I’m going to the vacuum test. What hose on a 1990 do I connect to?

[@FlyinMiataVideo]

@@Evansforrest A clogged injector certainly could cause a loss of power concern, but the description of the symptoms you're experiencing sounds more like an ignition concern. If an injector was causing this issue, the issue would likely be present all of the time (starting, idling, and under throttle).

[@FlyinMiataVideo]

@@Evansforrest You'll need to hook the gauge up in-line between a vacuum port on the intake manifold and one of the vacuum line attached to that port. If you're able to find an unused vacuum port, you could just hook the tester up to that port.

[@matthewaguilar3624]

Could a vacuum leak be causing my rpms to drop when coming to a stop but not stalling?

[@FlyinMiataVideo]

Yes, it's a big possibility!

[@coreysmith5397]

It can also be the "pot" that dampens the throttle slamming shut when you suddenly lift your foot. Visible on the throttle body. If you keep your fingers on the throttle wheel when you let it slam closed, you should feel a ~1sec delay before it actually hard stops