Intentionally cutting off engine airflow

Hey all, another odd question. @EatSleepTacos and I will be installing a snorkel on my truck tomorrow, and I’d like to ensure all the connections are airtight. I read somewhere on here that starting the engine and intentionally blocking the snorkel with your hand is a quick and easy way to check if everything is hooked up properly; basically, if the engine instantly dies, you’re good.

While I see how that method works, I’m worried that it might cause damage to the engine or other components. What do you think?

 

Stalling an engine isn't "good" for it, but if you do it once or twice its not going to actually damage anything. The mass air flow sensor and ECU will basically sense that there's no air, and adjust the fuel flow, until it just stalls, or maybe it shuts itself off.

I don't think anything bad will happen by performing this test once, but I'm no expert. Maybe an actual expert will chime in and contradict me, in which case, listen to the expert.

 

It wont be completely air tight. From factory, there are a few small holes (1/4in ish) in the bottom of the elbow going from your fender well to the filter box. They're to help let out any water that is taken into the intake prior to the filter.

 

I just want to go on record and say I’m not on board with this test and if you’re adamant about it, you’ll have to be the one to do it.

Its going to be hard to get it perfectly air tight, and I wouldn’t want it to be. As mentioned above there are a couple holes in the factory box to let any tiny bit of water that enters to drain out.

 

If you were to do a partial block for a second while trying to listen for any air bleed in the snorkel joints, I couldnt imagine that would be too big of a deal. I feel it would be hard to hear over the engine noise though. Just be thorough on the install. Snorkels are meant for dust, not water.

 

Even on my 4 wheeler that I ride under water for miles, doesn't shut down right away when the air inlet is covered. I dunno.

 

You're not going to hurt anything by closing off the intake. All its going to do is stall, it will start right back up

 

I second this. I understand where you're coming from, but there no sense in going out of your way to beat on your engine for no real gain.

 

I don’t really see this being a problem. Though I’m not sure the test necessarily means you don’t have air leaks. Just means you don’t have an air leak large enough to supply sufficient air to the engine. But maybe large enough for water to get in.

I think there is a leak test with propane (or maybe some other gas, I’m not really sure) that you blow over all the joints. Is air is being sucked in then it will pull in the propane and stumble for a bit as it runs rich.

 

im more concerend my cheeks sitting in swamp water

my snorkel looking like an interstate to some parasite

 

You're not beating on the engine by cutting off airflow. Engines are air pumps, and hefty ones at that. If they were that brittle then you'd be doing damage just by taking your foot off the gas quickly.

 

I am aware of this. ARB's snorkel installation instructions suggest sealing them shut, which I'm not planning on doing in a permanent fashion. Just a piece of tape or something over them to check airtight-ness, which will then be removed for regular use.

Ask @His Randyness about how painfully thorough I am. I think he's sick of dealing with me, but is too accommodating to say it.

Per ARB, snorkels are absolutely meant for water. Not that I'm trying to turn my Taco into a submarine.

I was thinking about alternate methods. Maybe a "smoke test" like HVAC techs use to check for leaks?

I see what you're saying, but I dunno if that's an accurate statement. There are copious amounts of electronics involved that kick in when you take your foot off the gas quickly, compensating for sudden lack of airflow (or anything else) within a margin of normal operating conditions. Suddenly choking off all airflow is decidedly outside of normal operating conditions.

I'm gonna wait for some more input before I decide one way or another. This engine is barely even broken in at 42k miles, so I am absolutely loathe to cause any issues with it.

 

It won't cause any damage to the engine to block off the airflow into it as you described.

 

Right but the "electronics" just measure airflow and engine speed/position. Take away the airflow and the electronics just report no airflow. Its not like anything is going to short circuit

 

Just make sure whatever you use to cut off the flow is strong enough not to get sucked in.

 

Also curious what the point of a snorkel is if it's not sealed up in the fender? Doesn't sound like an upgrade if you can still suck water in down where the factory inlet is

 

A better way might be to use some smoke around the joints while the engine is running. If there's a leak, it should get sucked into the joint.

 

Can confirm that it does not seem to hurt the engine, just makes it absolutely gutless. Though I would be skeptical of getting every last bit sealed off enough to stall it.. Especially at idle

 

Holy carp you guys really overthink asinine stuff. The throttle body is pretty much closed at idle, with just the smallest little gap for air. You're not going to seal up a snorkel so tight you kill the engine, and you probably wouldn't want to since there is no way for any water that might get in to get out (you want the little hole on the bottom).

 

So, wouldn't water then go in that hole?