Bypass pipe, now a vacuum leak

Good morning!
New to the forum, thanks for having me. My 06tacoma 2.7 with 180k miles is due (over) for a lot of repairs and maintenance, and I am learning as I go.
What I have crossed off the list so far:
All four struts/ coil
Front brakes
Reverse switch (that was leaking but I snugged it down and is ok now)
Water bypass pipe

still to go, may wait till spring:
-Oil pan is rusted at the seam, not leaking yet but I’d like to replace next oil change
-complete fluid change trans, front+rear diff, I looked up the oil and that’s going to be pricey


And now I am thinking I should have replaced the intake manifold gasket, throttlebody gasket, and a few of the vacuum lines while I was in there doing the water pipe. This was an intimidating project for me, and money is tight and the gasket looked ok so I left it.
After reconnecting everything the truck runs fine, I just took it down for inspection. But the first 10 to 15 seconds after starting up there’s a hissing sound followed by kind of a quick poof and then the truck operates normally.
Are there any other symptoms that would indicate a vacuum leak, any advice on pinpointing the source or should I remove the intake again and do the gaskets?
Thanks

 

Welcome to TW, Patti!

 

Welcome!

If It were me I would take it down again and replace all the gaskets involved. You should always replace the gaskets and seals when you reassemble. It prevents doing the job twice.

 

Yes that is what I will do. At least this time will be easy cause I have already done it, and broken through all the dam the rust.

I tried capturing the hiss poof/whistle pop sound when I started the truck this morning but it didn’t do it.

 

It should be a snap as you already have a practice run completed.

Wishing you the very best!

 

There is a small vacuum hose on the back of the intake by the firewall, passenger side.
It's really hard to see and easy to miss when putting it all back together after removing the intake.

Check for that before you take it all back apart, could be an easy fix.

And welcome to Tacoma world!

 

Welcome to TW Pat

 

When I double checked all the hose connections, I did make sure to look at that one. that’s actually the hose whose clamp was rusted and broken and needed to be replaced, also the end of the hose was a tiny bit dry rat, but not beyond the clamp. Is it possible that i reattached one of the hoses not on all the way, and the vacuum pressure when I ran the truck snugged the hose on for me? The sound has not returned, I only heard it twice right after reassembly. Now everything sounds and runs great.
Winter came back here, so I’m waiting for a sunny day to do any more non-emergency projects
And thank you for all the welcomes and advice!

 

Dry rotted hoses need to be replaced

 

Will do, in spring. Along with new gaskets and a thorough cleaning, that leaking coolant did a number. I don’t have a garage, so if it doesn’t leak and drives good then I’d better wait for good weather.

 

Hiss and then poof might be the air injection pump cycling on, normal on cold startup

Do you have a little scan tool that can read codes and data? Long term fuel trims would quickly tell if you have an intake leak

 

“Do you have a little scan tool that can read codes and data? Long term fuel trims would quickly tell if you have an intake leak”



I don’t have a scanner, is it the same code reading tool they use at the auto parts store to diagnose check engine light? And would having the battery disconnected reset/ clear out the old information?

 

Mine snapped off from being old. I jb welded it a few years ago. It's still holding up. Problem solved

 

"Oil pan is rusted at the seam" You might want to clean it really good and use some JB
Weld - It's worth a try - It's expensive to replace the oil pan - JB Weld is next to nothing in comparison.

 

Years ago, I did the JB Weld to my then girl friend's Chevy Vega. It held for a long time, at least to junk yard.

 

Curious - What's a long time ?

 

I bought a purple ‘75 Astre from the original elderly lady. Perfect purple interior. On my way home I opened the ashtray and it was perfectly clean with the original dealer key tag. It was the most fun car until the tree fell on it. Edit: shit and I paid $185 for it and drove it for 3 or 4 years

 

Over two years and then I lost contact with her and the Vega. I was not disturbed by the loss of either.

 

Sounds like it's worth a try .

 

T

Thats what I was gonna say. Mines always been loud on cold start then poof and quiets down