left front fender well tank??

what is that for and can i just block it,

 

edit: for correction

Dirty Pool gets credit
for the correct answer in his post.

ADD vacuum tank

 

do i need that ?

 

Yes. It's part of the EGR system.

Unless you delete the whole system. Which is a PITA without removing the motor.

 

That is a vacuum accumulator tank for the ADD system. It allows for a steady constant vacuum to the ADD VSVs. At least on a 99 V6 it is. Follow the hose back to see for yourself.

 

^ yer right and I was wrong.

* previous post edited to reflect

If the vacuum cannister is fubar...
wouldn't the ADD fail to engage/disengage ?

 

EGR and EVAP are two separate systems dudeeeeeeeeee

 

don't blame him...
it's probably my fault for posting incorrectly

Dirty Pool pointed out my unthinking booger...
and I edited my original post for correction.

sorry I posted the wrong info

---------------------

OP

[FONT=Arial,Helvetica]"If the ADD system does not properly engage the front drive mechanism, the first items to check are the vacuum supply hoses. First, look under the hood and locate the ADD solenoids. Ensure that the vacuum hoses are connected to the solenoids or vacuum switching valves (VSV) as they are commonly called by Toyota. Next, look at the hoses at both the differential and vacuum reservoir located in the R/F wheelwell. Make sure all hoses are connected and not torn, cracked, or otherwise in poor condition. Once the system is engaged or disengaged from 4WD, it will stay in that position. Basically, if the system is not functioning, the vehicle can be placed in either 2 or 4 wheel drive manually with a vacuum source for testing. If you plan to leave the ADD system disconnected you will need to apply vacume from the engine to make sure the front end does not unlock."

fm: http://www.off-road.com/trucks-4x4/tech/the-automatic-disconnecting-differential-system-19259.html [/FONT]

 

I unplug the hose from the vacuum cannister, and and everything still work so i might try to plug the hose or relocate with small plastic canister in the hood

 

Yep, I wouldn't want to think what Toyota gets for that tank. A short scrap of 3" PVC or ABS pipe with 2 end caps. Epoxy in a little tube for the vacuum hose and you will be good to go. Heck, with just a little effort it could be made to look stock.

The system should work well enough with the hose off and plugged at low throttle (high vac). The whole point of the tank and the little check valve right after the vac source is to provide vacuum when the engine is not making enough on it's own (lots of throttle). Kind of like a "vacuum battery".

If the ADD system is working with the hose open there may be a clog somewhere. When that tank first got a hole there would have been a vac leak that could have sucked in some crud and plugged something up. Might be a good idea to check.

 

Hey I know this is a pretty old thread, but has anybody ever had any luck finding an aftermarket vacuum tank on ebay for this truck?