Well just got my exhaust welded up and i cant figure out why i have no brakes. Bled the system, put a one way check valve in between the booster and vacum port, and still nothing. Im also getting a high/surging idle. It will start up and run at about 2200 rpms and jump down to 1200 back and fourth. I still need to hook up the vsv's and plug in the o2 sensors but you guys have any ideas or suggestions? Thanks

 

No brakes or power brakes? With the engine off, does the brake pedal feel correct (a bit of resistance) or does it fall to the floor? Is the booster line plugged in somewhere that actually generates vacuum (un-plug it with the engine running and put your hand there and feel for suction)? Is the check valve in the correct way (disconnect the hose at the booster and check for suction)? Did the power brakes work before the swap?

For the idle...are you throwing any codes? Test your IAC and MAF to verify they work correctly, clean them both (they'll likely need it anyway). Make sure you don't have a vacuum leak from not having the VSVs hooked up (not sure if this would cause a high idle or just a sporadic one). Plug in those O2 sensors, they play a bigger role than most people think (at least the first one does).

 

DId you ever hear this motor run before the swap? Did it idle correctly then?

I had HIGH idle on both of my swaps at start up.
One was the throttle cable improperly adjusted. Tried fixing by tweaking the bracket with a crescent wrench, but ultimately had to go back to the stock 3.0 cable and I could just never ge the 3.4 one to work right for whatever reason. Been a LONG time.

Second was the IAC valve, and combination of crap buildup on the butterfly.

There is a good IAC writeup in the 96+ forum that I used, but i just looked for it and i cannot find it. Try searching for IAC writeup and you may.

As far as the power brakes go, everything that SacRunner stated, is what I would try too.,

 

I think that the old write up in the 96+ section is gone. At least all the pictures were.

Here's another
http://www.toyota-4runner.org/3rd-ge...-iac-pics.html

You don't need the 90degree screwdriver. Those screws can be a female dog but just go easy and you be fine.

 

So with the engine running or not, there is resistence but the pedal goes to the floor. Same amount of pressure all the way to the floor. When driving there is no stopping power even when I pump the pedal. The check valve is in the correct way, and the booster line is plugged in where it is supposed to be.

 

You verified that you are pulling vacuum thru the line to the booster. If so, this sounds like the same things my daily driver tacoma was doing. I ended up having to swap out the booster.

May be time to do that.....at least try another one? Might be a good reason to upgrade your booster and master. Can't remember if you have a donor vehicle but my buddy put the booster and master off my 97 Runner onto his first gen runner and he said that stopping power was an incredible difference.

May be a blessing in disguise.

 

So a 4 runner or taco booster and master will bolt up and fit an earlier model? Donor was a 2000 4 runner /5 speed 4x4. My truck is a 93' x-cab 4x4 , 5 speed.

 

went into my buddys 85 without issue

 

Well its not the booster... I confirmed im getting good vacuum through the line. I don't know. This is driving me crazy! I just wanna drive the dam thing. Onto the high idle, its up there right around 3000 rpms. I cleaned the IAC and changed the TPS. I do not have the VSV's plummed in yet because im unsure how they are supposed to be. Plus im not sure if I even have the ones I need. I would like to just eliminate them if I could, or just route them using the 3.0 canister... If someone could take a picture of the three that are needed and how they mounted/set them up on there fender or firewall that'd be awesome! Im thinking my main problem leading to no brakes and a high idle has to do with vacuum routing.... I got rid of the stock air box and am running a AMSOIL cone filter and also eliminated the intake silencer box...Im at a stand still right now.....

 

Bump!!!!

 

It really sounds like you still have air somewhere in the brake system; the pedal shouldn't make it all the way to the floor.

I would get a buddy and re-bleed the brakes the long way; open the bleeder valve, push the pedal in, close the bleeder valve, release pedal, and repeat until no more air bubbles. Or let it gravity bleed, make sure the master cylinder is full, open a bleeder valve and let gravity push the fluid through, making sure to refill the master cylinder before the fluid gets too low.

No real advice on the high idle.

 

Well i cleaned the hell outta the IAC valve again and the idle is at 750. Finally! Gonna throw some new calipers on the front and see if that changes anything. The brakes are now the only thing holding me back from driving it other than in 4 low. So close !

 

Well these brakes are kicking my ass! New pads+calipers up front. Bled the hell outta the system. Its gotta be to do with vacuum of some sort. I have some of the ports on top of the plenum capped so I don't know!!! Could somebody take some pictures of their vacuum routing so I can verify mine. Also what are signs of a faulty brake booster??? They don't usually go bad do they??

 

You said you have good vacuum but have you tried swap out the booster? Your brake pedal should go hard without the engine vacuum. If it doesn't, it might be the booster itself.

 

Gonna try a master cylinder in the morning. Will post up after

 

So I replaced both the booster and master cylinder......And still nothing! I have searched for leaks such as a pinched brake line or something but have no idea anymore? Bled and Bled and Bled the system and there is no air in the lines. I have no clue what to go after next.

 

Did you bench bleed the master cylinder before installing?

 

Yup. Im completly stumped.

 

Can you just plug up the two holes that goes to the calipers and see if the pedal gets hard?

 

So let's start at the beginning of the system.

You've changed the booster and master and bench bled it. Changed the front calipers. Bled and re-bled the system.

All seemed good. Booster and master were KNOWN to be good?

I think I'd pull all the lines and blow them out with an air compressor. Make sure everything is clean. Possibly something got in there during it's sitting stage? Debris, insects, etc.

I'd be stumped too I think but it has to be something. Time to start over with troubleshooting. Maybe post up in the main 86-95 forum and maybe even the 96-02 as well. You'd get more eyeballs and maybe someone would have a winning suggestion. I'd start isolated individual components. Plug off the outlets from the master, if all good, plug off front right, etc until you find the issue.