What is this noise?

S

sutton61

New member
I'm hearing a noise coming from my O1. It almost sounds like a vaccum operated door or valve of some kind opening and closing. I seem to hear it more when I first start it up while sitting inside the cab. It doesn't matter if the ac is on or off and everything seems like it is working okay. Any ideas?
Thanks
 
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I saw something on another web-site about VSV ticking? Is this maybe what I am hearing? It seems to happen more when I am using the brakes, coming to a stop and when backing up slow and coming to a stop. Any ideas?
Thanks
 
really hard to say without hearing the sound, but offhand, it sounds like something's rolling around in your truck somewhere, hitting the opposite side when you stop??:confused: any idea what general location the sound is coming from?
 
sutton61 said:
I'm hearing a noise coming from my O1. It almost sounds like a vaccum operated door or valve of some kind opening and closing. I seem to hear it more when I first start it up while sitting inside the cab. It doesn't matter if the ac is on or off and everything seems like it is working okay. Any ideas?
Thanks
Click to expand...

If it happens at start up maybe the fuel pump?

Just a guess.
 
Thanks for the replys everyone, but this is different. I know those sounds. This is almost like something is operating or cycling. It's the same sound everytime. I'm starting to think it has something to do with the ABS brake system? maybe? Thanks for the help, its most likley something normal but now I'm just listening for it more now that I've noticed it.
 
re: pump noise

Most likely its your hydraulic brake booster pump. It cycles on and off to maintain proper brake fluid pressure in the master cylinder. My 01 does the same thing and it's normal. Most noticeable is the loud click you hear when the pump relay switches the pump off.

I just got my 01 six weeks ago - aint it grand?

Cracker
 
Thank you, I thought it was something like that. Yours does it often? I'm wondering if there might be a leak in my brake system. Mine will make the noise about everytime I stop. What do you think?

Love the truck!
 
The pump goes on for about 5 seconds about every fifth braking action in my truck, and it runs for about 20 seconds when started in the morning. Others with the same model report the pump runs at about the same rate. If it runs every time you stop even when you are in stop-and-go traffic, well, I might be concerned about a problem. But if there was a leak you would detect that by looking at the level in the fluid resevoir, right? So if the level isn't dropping, I wouldn't worry about it.

Have fun.

Cracker
 
Thanks for the reply. Sounds like what my truck is doing. Wasn't sure if maybe I had "vacuum" leak somewhere in the system. Sounds like everthing is normal, I push the brake pedal 5 times and the pump will kick on. I guess the noise I'm hearing is the valve closing after the correct pressure has been reached in the system.

Thanks again
 
I hate to keep going back to this, but if my pump kicks on when ever I push down on the pedal(when in park). You had said it should hold for aprox. 5 cycles. Where would I start looking for an air leak? Could my brake booster be bad. Any ideas on this?
 
Hmmm. I took mine out and warmed it up then parked it and started working the brake pedal. My booster pump turned on about every fourth or fifth press on the pedal.

You should not find any air (or vacuum) in your brake hydraulic fluid system, so I would rule out air leaks. It may just be a factor of how quickly fluid moves out of the pressurized system into the fluid resevoir. I don' t know why yours would behave differently.
I might suggest that your master cylinder has a bad valve that makes the system lose pressure quickly when the pump is not operating. But I'm no expert on this system. I only know it does not use a vacuum resevoir for boost.

Good luck.

Matt
 
Thank you for your reply, I have also noticed now that I am driving in a different traffic pattern, mostly the stop and go in the Atlanta area, the brakes seem to grab all at once during a panic stop. I am thinking this is a problem. The air leak was thinking it may be would be in the vacumme side of the booster, not the hyd side. Maybe I don't know enough about the system to be talking about it. I do know the brakes on my Tacoma are nothing like the ones on the 4Runner.

Thanks again,
Steve
 
I went to the dealer today and I was told my ABS motor was making the noise and it would only get worst. I have not had any problems and the ABS system is working, just keeps cycling. I was also told this motor had to be replaced along with the whole ESU. Total for parts $1500? Plus who knows how much for labor. Any feedback on what I was told?
 
Wow, that's the first time I've heard of a dealer recommending a new pump. Then again I've never heard of a pump running as much as yours does.

BTW, the ABS pump is the same as the brake booster pump that I've talked about. I don't know what ESU means. You sure he didn't mean ECU? There's a Skid Control ECU for instance. It's the main brain for the braking system.

Have you thought of going to another dealer for a second opinion? Wouldn't hurt. Don't tell them there's something wrong, ask them if something's wrong.

Good Luck.
 
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