cold start noise - SAI issue?

06 sequoia – 240k miles, well maintained. Month or two ago started getting a faint “squeak” when starting the truck (right when it fired up). Started about the time the temperature started dropping and it’s only noticeable when it is cold outside and the engine is cold. Does not make noise when engine is warm. It’s been getting gradually more noticeable (along with the colder winter temps). This morning along with the squeak there was a noticeable “whine”. Drove it around the block and the whine didn’t go away. I'm assuming the two noises are related. Have owned this vehicle for a few years now and have had my tundra for 12 years. it's not a pulley/belt type whine (which both my vehicles have), definetly sounds like it's more in the engine. This was a new noise I’ve never heard before. it was dark and cold and I had to get to work so I parked it and took tundra.

I know it’s impossible to diagnose based on descriptors like “squeak” and “whine” but gotta start somewhere… haha.

I thought I read somewhere that the secondary Air injection system can make some noises when it’s on the way out? (But may be getting that confused with something else). No check engine lights on at the moment. I’m thinking I’ll order a Hewitt bypass kit and do that regardless as its been on my to do list given the age and mileage of vehicle. Going to get the stage 1 kit.

Besides the SAI I don’t really know where to begin looking. Won’t have time to dig into it more until this weekend, so in the meantime I’m here hoping for some suggestions. Winter is here and I need my best winter vehicle!

 

Considering the age and miles, I would first look at squeak and wine- bearing type noises. Check fan clutch, alternator, power steering components. All of those can makes those noises when they start to go.

would be helpful if you can post up a vid.

 

i've definitely got some more digging to do. doesn't sound like a belt or pulley squeal (although those do make cold start noises on both my trucks...). Its similar to a PS pump whine, but coming from the engine. will try and get a video posted if its still making the noise tonight.


digging through forum and found several instances of SAI pump whines and noises. since that has been on my to do list I went ahead and ordered the Gen 1 bypass kit from Hewitt. Will plan on installing that regardless, might get lucky or will at least be able to rule it out.

 

Installed the Hewitt SAI bypass over the weekend. Didn't get rid of the startup squeak. Verdict is still out on the whine... Hasn't been noticeable last few days but I think weather has a lot to do with that. Either way I'm glad the bypass is installed.

The start up "squeak" as I'm calling it is noticable in the video below. Right after it fires and it's just the one chirp. Anyone dealt with this before? It's a pretty unique noise...

I've got a new drive belt I'll install this weekend. Fairly noticable cold belt/pulley noises are making it hard to pinpoint these other more concerning noises. I'll check the pulleys/idler/tensioner the best that I can.

 

Need someone to start the truck while you under the hood localizing the sound. Then bust out the auto-stethoscope to pin-point it.

 

That someone would be my wife and it would need to be on a weekend morning (it's cold)... wish me luck, haha

Good advice. That's where I'm headed, tried that last few days but the serpentine belt noise is making it harder to pinpoint, so that's the next step.

 

Was able to find just enough time on Sunday afternoon to install a new belt. It helped quiet the obvious minor belt noises. But did not fix the starting squeak/chirp (see video). Still, glad I did the belt, it was $18 well spent.

The "whine" noise that was very obvious one cold morning a few weeks ago has not come back. It hasn't been as cold since then. Thinking that's power steering pump and unrelated to the chirp. I loaded up PS system few months ago with Lucas PS fix which is thicky thicky thick... Worked great over the summer, but now that's it's cold, maybe less great. So I'm ignoring the whine for now. Just focused on the chirp. Will come back to this when I get the whine again (it's been a warmer than usual december...)

Next step will be to start truck with belt removed. See what that shows. Given the chirp is only when its cold I haven't gotten too many opportunities to stick my head in there while someone starts the truck (no one to help when I leave for work). With winter break coming up I'll have more opportunities to try and better pinpoint it.

 

There's a TSB for that...