well i got a second hand replacement from R-fastmotorsport and installed it earlier tonight. On my test drive the engine still revs a bit when i press the brake pedal and then let go when at idle. I can't tell id it does it at speed. However, the replacement has for some reason made the engine performance HEAPS better. Lot more power when accelerating. Why is this? Cheers.

that doesn't sound normal!

shouldnt be like a duck call!

should be free flowing in one direction, and not flowing at all in the other

maybe it is blocked/jammed

when you jiggle in your hand you should be able to hear and feel the slide mechanism going back and forward inside it, it should move very easily, and if it is operating correctly it will not restrict flow much at all, should be like blowing in a maccas straw

essentially there is just a solid cylinder in that valve that slides from one end to the other depending which way air is flowing

you should not be blowing you should be sucking, the engine sucks through that valve to pull the diaphram in the brake booster, you should be simulating that by sucking on the engine side of the valve (by doing this you are pulling the cylinder inside the valve to the engine side, this is allowing flow through the valve, so actually this is the same as blowing from the brake side..... you should be able to suck through the valve from the engine side or blow through the brake side.... and not the opposite scenarios)

edit[] the whole engine rev when brake thing is not particularily dangerous, although its not great, essential you are accelerating and braking together, which obviously is going to increase your stopping distance. you should definately fix this problem as a priority, although personally i would still drive it carefully if i had no alterative.... maybe to a brake place so they could fix it!

Thanks rally.

Took the valve off and tested it out. It was installed the right way. I blowed on it and it kinda sounds like a duck call used for hunting. Kinda hard to get air out the other side, is this normal? Sprayed a lot of WD-40 in there as well and put it back...the same way of course. One side is brass-ish color (the blow side) and the other end is the same color as the shaft. There were no markings on it that I could tell other than the letters E-K1 whatever that means.

Could the problem be at the ends? Where it meets the booster or the opposite end where it meets the valve on the manifold?

How serious is it to have the engine rev about 500 rpms when I touch the brakes and again when I let go of them?

edit: diagram indicates direction currently installed.

Cheers.

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wire connection orientation doesn't matter

the valve is the piece half way along the hose,

benny is talking about the small tube from the inlet manifold, it looks like its bent over backwards and twisted to seal it but would be good too see some rubber or sealant over it. This is separate t your brake pedal = engine rev problem


You need to check out the valve (half way along the length of the hose, from inlet to brake booster) i can see it is there in your picture. but you need to make sure this is inserted in the correct direction and is operating

check out if it has an arrow on it and take a picture for us

take the valve off both hose ends and check the mechanism is moving inside it, spray it with heaps of WD40 to clear it out

if you suck on one end you should get flow, if you suck the other you will not. the end you suck and gets flow needs to be the side which is connected to the hose that goes to the inlet manifold

i can not see how any other thing could cause your phenomenon of engine revving when hitting brake pedal

Thanks for the responses guys.

I had a look at the brake pedal where the switch is located and fitted a nut and bolt there (as suggested) since there was an empty circular hole where the switch fits in to, as you guys guessed correctly. (see the red arrow) I'm thinking that mashing the pedal the other night broke away whatever was there before. So the brake lights work properly again! Hooray!

Does it matter where each of the two green wire ends go on the switch? It seems to work either way and I didn't label them before I took it off.

As far as the rev issue...Benny is that valve out of the intake supposed to be blocked? I'm confused.

Cheers.

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Looks like the fitting in the inlet manifold is also not blocked off on the little tube that connects the the main fitting. Having this not blocked will lean up the fuel mixture. engine idle will be effected also.

Quote:

"nice products" do a direct replacement brake switch for B110. part number BS26. spend around $10, and your done.

valve must be in wrong way, pushing brakes is pushing air in to the inlet causing increased revs

the valve should allow the engine to suck air from the brake booster, take the valve out (disconnect hoses from both ends) and ensure you can do that (by sucking on the inlet manifold side) to check it is installed in the correct direction, if it has an arrow that should point towards the motor side not the brake side

eidt[] the brake lights is probably the switch as said above, the brake pedal actually presses this switch in to turn off the brake lights, it may need adjusting but more likely the plastic piece that actually pushes it (part of brake pedal) has perished, these are often replaced with a bolt and nut on the ol' dattos these days

As far as the brake lights staying on I'd say its something to do with your brake light switch, go to the brake pedal and look up until you see a switch, might be something wrong with that or might need adjusting. As far as the engine revs I think you have a vacuum leak somewhere as the others have said. Sorry can't be more help.