Is this a vacuum leak? (1 Viewer)

[60 toy ota]

So. I did a valve adjustment (nothing was really out of spec) and got a stumble/hesitation upon putting everything back together. drove it once and the new cat was red hot. New noise in exhaust under load (can be heard in the video) (EDIT: would a new cat sound like that??). I even thought I could hear a hissing coming from the back of the engine. So far everything seems like I vacuum leak, right?

Here's what I've done so far.
I sealed off 2 hoses to take the valve cover out of the equation, no change. found a crack in the intake tube (HALT! I know what that means and will replace it. However, I didn't hear anything there through the stethoscope, and nothing changed when I sprayed carb cleaner all over it. Covered the area with duct tape, no change.) Sprayed carb cleaner all over the place and couldn't get any response from the idle. Hooked up a vacuum gauge and expected to see something between 5 and 10, but it was reading at 16. From what you can see in the video and my description, I'm headed in the right direction with the whole vacuum leak suspicion, right? Can you see anything I'm doing wrong in my testing?


Drew

 

[CaptClose]

Hey Drew... a hairline crack will leak more air after the engine is warm. Idle it for a while and see what happens with the gauge.

When spraying that carb cleaner, go heavy with it. You'll never find a leak doing it the way your video shows. Hit the usual places like the base of the carb and all around the intake manifold. There's no need to spray the valve cover. Get under the the car and spray up toward the bottom of the intake as well. Listen carefully. Avoid the distributor area.

 

[Output Shaft]

What is your altitude?
16 in.Hg of vacuum is low for sea level (should be near 20) but can be normalish up in the mountains.

 

[60 toy ota]

ah good point, I'm at 4500 ft

 

[60 toy ota]

Hey Drew... a hairline crack will leak more air after the engine is warm. Idle it for a while and see what happens with the gauge.

When spraying that carb cleaner, go heavy with it. You'll never find a leak doing it the way your video shows. Hit the usual places like the base of the carb and all around the intake manifold. There's no need to spray the valve cover. Get under the the car and spray up toward the bottom of the intake as well. Listen carefully. Avoid the distributor area.

I should mention that although it's a 60 I've ditched the carb for the 62 injection, thus the thought about the valve cover. I doubt it's a crack because it only started doing this after the valve adjustment and it behaves this way weather the engine is cold or hot. But thank you for the tip on the spray

 

[RockDoc]

I've had a vacuum leak at the gasket between the upper and lower intake manifolds o my 2FE. You plugged the PCV and fresh air feed that hook up to the valve cover? That would eliminate the back of the valve cover gasket (which is easy to get out of whack with how tight clearance is with the 2FE In a 60/62). Any other vacuum hoses disconnected? Brake booster? Intake hoses loose at the clamps?

 

[60 toy ota]

yeah I plugged/checked all those, and I didn't take off the throttle body or manifolds, just the intake tube and air cleaner cap. I did disconnect a few hoses around the brake booster area, but couldn't find a leak there. I'm about to buy new hoses just to eliminate that possibility, and because they're old anyway. If that doesn't do the trick...well, let's just pray that'll do the trick

 

[60 toy ota]

I hate reading posts that have my same problems but no solution, so I won't be that guy. It eneded up not being a vacuum leak at all, it was something stupid simple. My #1 spark plug was disconnected where I didn't see it, causing the stumble, hot exhaust, etc.

 

[LAMBCRUSHER]

good follow thru!