CrazyJoker

I got an 87 TurboII with no cats and no airpump, but Im not sure on how to disable the damn ACV valve. It's still pumping out air, cause if you put your hand next to it you can feel the air pumped out, and you can hear the ACV working as well. But the main reason I need to disable it is because my checkvalve behind the ACV has gone bad, and because of this, exhaust fumes are venting out of the ACV and get pulled into my vents and make my car smell like exhaust fumes, and at higher revs you can even see some smoke come out of the ACV hose. To remedy this, I just put a hose on the ACV and plugged it at the end so the exhaust couldn't vent out, but I'm concerned that this might not be good for the engine. If I plugged up the ACV, then where is all that air and exhaust gas actually going if it's not venting out? But oddly enough I noticed that after I plugged the ACV, my boost hits harder and the car definetely pulls more at higher rpms with less hesitation. How could this be? Can anyone help me out here??

CrazyJoker

bump

tesla042

Not sure if the turbos are the same way.....but on the n/a's, you can block the ACV off. You get to take off the lower intake manifold, and fab/buy a blockoff plate.. Unbolt the ACV, dropkick it, cut some gasket to the size of the blockoff plate, maybe some gasket sealer too, and screw it on.. all done!

-Tesla

CrazyJoker

Thanks for the info. But does anyone know of anything that I can disconnect in order to disable the ACV valve without removing it?

jrussell

I have an 87 T-II also and I just bought the block off plate from MazdaTrix, and get a gasket too if you don't have a new one. You will need to drill and tap a hole in it near the top bolt for the boost sensor and get a nipple for it. You can tell where the hole needs to be from the gasket. Then take off your ACV and put on the block off plate at the same time. You may want to do your EGR valve and split air pipe at the same time while you are there.

You can easily make your own too if you have the equipment.

I don't know for absolutely sure, but the exhaust gasses that used to go to the ACV should just go out the exhaust now.

13BAce

I just use the blockoff plates RB and Mazdatrix sell--the same part. If you don't have a gasket you can just use silicone. There's no need to tap anyholes for a vacuum nipple. I don't know why they say you need to do that. Just make sure that you cap off any open vacuum nipple. Mazdatrix sells a split air blockoff plate.

Keith

No, you cannot totally disable an ACV. The reason for this is that the Anti-Afterburn valve is enabled by intake manifold vacuum, and it is connected to it's source internally. If you could put the ACV in permanent relief, you could do it, but on a TII you need air from the air pump to do it, and you don't have that. Remove the ACV, it's your only option.

Irv, Keith's dad

ROSHX7

Hey guys, I WANNA know the ANSWER to this guy's other question! LIKE IS IT DOING any damage by plugging UP his ACV hose that goes to his airpump? Cause I got my airpump off the car and that hose that goes from the ACV to the Airpump is just sitting there opened and I think I might be losing some exhaust gases out of it too...is there any harm in JUST PLUGGING that sucker up completely?

CrazyJoker

Exactly, thats what I'm doing to my 87 Turbo II. I just put that hose back on and plugged up the end of it because I couldn't take the smell of exhaust gases venting out and getting inside the car. I immediately noticed better acceleration, and the boost hits harder now. Maybe it's because my checkvalve inside the ACV is bad and letting out exhaust gases, but whatever it is I still wanna know if running this setup is ok.

NCsublime

I can't guarantee it, but I'm almost positive that it is perfectly fine to just plug it up. A block off plate would work/look better though. That is why they are telling you to use the plates.

Good luck,
Derek

natedogg

I have an N/A with down pipe and pre-silencer from RB and I had to completley remove my ACV and block the opening from the tube that I unplugged from the airbox.

You will have to plug the hole left by removing the ACV. That isn't hard you just have to be patient. Use a metal plate, perferably something strong. My plate is about 1/8 inch thick with three holes used for mounting. Mazda put a double threaded nipple on their that you will have to unscrew to put a plate on it. You will need to remove it with a pair of clamping pliers. Then Just using gasket sealer should be sufficient. Something with a copper base.

Good luck!