Whats the Vaccum Box do?

[Janiel]

What does that black box in the engine bay do? Could that be causing the surging of my motor at idle? It has 8 hoses coming out of it.

[shepherd79]

you have LXi, so it is hard to tell what it is for. i would guess it is for emission crap.
look under the driver seat from back. you should see computer. see if you can see any lights. if it is blinking, count how many times and come back for the answer.

[anchovies]

I think chiltons have a description of what that box does. Emissions definitely. EACV, EGR valves, switches and stuff if I remember correctly.

[cruznz]

i've scanned it ...if someone wants to post it....

[AccordEpicenter]

Yeah it controlls some idle valves and it has some sensors in it and some vaccum solenoids. I have the same problem and all my lines are good and ive changed my warm and cold idle valves on the intake manifold... Im startin to think it could be that stupid box. Mine will do it when you start cold and then shift into drive or reverse or what not, and then go back to neutral and idle, and it will do it then untill it warms up completely. Im thinking a vacuum solenoid is sticking somwhere and leaking... any ideas?

[HondaLuxury]

I hate to say anything bad about hondas, but i personally think that all of that shit has no purpose. My mitsubishi has many fewer sensors and wires under the hood. it does just what the honda does, and it rated the same as my 4g when i smogged it. that is one thing that I think honda should work on. eliminating the crap

[HondaLuxury]

excuse me, i meant 3g

[Janiel]

Ok this shit is pissing me off! When I start the car it rev's to 3,000 rpm and after about 7 to 10 seconds it goes to a 800 rpm idle. I changed the vaccum box from a car that worked fine and it did do a thing. I took the cover off that sensor thats right behind the TPS and it looked like new (well from the top). Do I have to take it out to clean it?

[Mike's89AccordLX]

Uhh I removed my black emissions box. But, I have an LX so yeah.

[carotman]

The Map sensor is also in this box.

Check your EAVC Valve in front of the intake manifold, cleaning it might do some good.

[Janiel]

Ok the little light doesn't blink at all. But yesterday I unpluged something that is in between the fuel injectors and the intake manifold which is actually on the manifold. The plug that i unpluged runs with the wires that feed the fuel Injectors. My car works fine now. But what does that thing do? And why didn't the check engine light come on when I unpluged it

[cruznz]

possibly air temp sensor......test it same way as testing coolant temp sensor

[anchovies]

Originally posted by Janiel
Ok the little light doesn't blink at all. But yesterday I unpluged something that is in between the fuel injectors and the intake manifold which is actually on the manifold. The plug that i unpluged runs with the wires that feed the fuel Injectors. My car works fine now. But what does that thing do? And why didn't the check engine light come on when I unpluged it

That should be for the EACV. Did you already clean the fast idle valve at the back of the TB?

[cruznz]

yeh...anchovies is correct....its the EACV(damn,..keep getting my models mixed up...sorry guys)....i can email you scanned idle adjustment instructions and diagram

Pete

[MrBen]

"you have LXi, so it is hard to tell what it is for. i would guess it is for emission crap. "

Haha that's funny. Emission crap.

[Sm0kin]

I have an accord lxi 86 model. my engine also revs up and down while at idle. It stops when my ac compressor is on and starts again when it kicks off. I had a friend of mine hook it to some sort of diagnostic tool and he said it was my throttle position sensor or something. when we got the part in he talked to a guy at honda(friend of his) and he said they had to replace 4-5 different sensors on a car same make and model. total on that from honda was around $700. so i gave up on it. I think eventually i will just replace all the sensors.

[AccordEpicenter]

its tough to say what each vaccum box does because the 86-87 and 88-89 boxes are different, and so are the intake manifolds etc, not to mention carb vs efi

[Janiel]

Well all i care is that my car runs ok now. Only when i turn the wheels, turn my bass on, and my fans come on the car sometimes turns off. I think i just need to adjust my idle.