Turtle's TII

I Have 87TII I think I have an unmetered air prblem. I read once that sucking on the ACV nipple that sticks straight up should hold vacuum. Mine does not. Is it bad?

If so What can I do to block it all off to prove this is my problem? The car will not idle, when it is fully warm it will idle sometimes, then it hunts up and down.

I Have fixed every vacuum leak and can not find any more with my trusty can of carb cleaner. The boot from the AFM to the turbo is perfect, except it has a loose fit at the turbo so I will put a different clamp on so I can make the connection tighter.

Car runs awsome other than idle issue, and some hot start issues. Easily clear floods and restarts, will run the AFM or a fuel pump switch to fix this. But want it to idle first. Everything seems to check out fine this is why I think it's unmetered air.

Thank you for your time,
Terry
87TII
94 Formula

jimmyv13

The ACV sounds bad. If you don't emissions in your area then take it out and install a block off plate and plug all vac lines.

HAILERS

The one sticking straight up, right next to the one that points straight out at you as you face it, is the swithching diaphram. Mine is broken also. Just plug the vacuum line. Not a big deal in the scheme of things. Just one of those small 10mm bolts laying about in the line will do. Don't worry about the acv itself. That part cannot cause your air leak. But if you leave the vac line on the acv, then you have a small air leak, because the diaphram is busted in the acv, and that means you might as well just take the line off and lay it hanging in mid as to leaving it hooked to the nipple. That loose connection at the turbo inlet is not a good thing. Take the plastic belly pan off and idle the engine. With a full can of starter fluid. direct the spray at the connection. If no change in idle, its probably good. A sad idle might be a result of somebody messing with the variable resistor. Its the pot near the boost sensor that is black and oval in shape with a R and L marking on it with a screw in the middle. Screw turns about a half full turn. Usually somewhere in the middle of it travel. The factory service manual at http://www.iluvmyrx7.com/Technical_I...ice_manual.htm in section 4b for the turbo, shows better than I could explain, how to set the idle using this variable resistor. Another thing that can screw a good idle is differences in compression b/t rotors. Might check this also. You can figure the fix for that if not close to each other. P.S You don't wanna rid yourself of the acv because the switching diaphram is bad. It has other functions that still work like anti-afterburn and relief, and port air etc. Also look at the words at this site http://www.mazdatrix.com/b-egr.htm

Turtle's TII

Made a block off plate and it seems to run worse down low and sounds like it has an exhaust leak.

So sounds like I should put the ACV back on and just plug the vacuum ports. Correct?

I have three even bounces at 85psi on both rotors. I have a good EGR valve.

Turtle's TII

Just noticed there is a very small hole in the side of the 4 bolt plate in the middle ACV. It's at the 5 o'clock position. This is causing a leak at the nipple that sticks straight up. Looks like somebody drilled it.

I doubt it's factory. The ACV diaphragm seems to operate fine. All I no is if I spray carb cleaner at te ACV the car will idle.

HAILERS

Should not have run worse. Acv should have had no effect on the idle when it was removed. Question: What did you do for the vac line that runs from the top center of the acv to the boost sensor. You have to have a vac line going to the boost sensor. The other vacuum line that points straight up in the air, and is next to the boost line that points straight out, needs to be pluged with a bolt, whatever, stick, dowel etc. Acv should not have had any effect on the idle. I suppose you took the belt off the air pump? Again, you have to have a vacuum line running to the boost sensor, cause it you don't it'll run real, real bad and your ECU has no idea what boost your at.

Turtle's TII

It sounded like an exhaust leak. I think my nuts bottomed out and did not have the block off plate on as tight as I thought. I will try again with washers.

Should I just run the ACV and block off a specific vacuu port? I had the pressure sensor hooked up to intake vacuum.

Also I do not have a pils in the pressure sensor vacuum line. SHould it have one?

Pacey3182

When I made my ACV block off, I drilled a hole through the plate, centered over the small orrifice. I then pressed in a brass barb. Connect a vaccuum line from the barb to the pressure sensore.

Pacey3182

You can use ACV gasket as a template.

Pacey3182

You can go to your local auto part store and get a vaccuum resticter to replace the pill. I did, but I don't have the intake back on yet, so I can't tell you if it made any difference. I can tell you that after I took the ACV off, ( maintaining the vaccuum to the press sens), I noticed no diference in idle or performance. If anything, it was better, and does away with about five hundred potential leaky vaccuum lines.

HAILERS

Pill: YES With no pill you will have a large and intermittent jerk at high boost or rpm. Similar to someone pulling off a plug and shoving it back on in a millisecond. Won't be a solid, steady jerk, just happen intermittently. On the ACV you could have left it in place and just plugged the vac hose that went to the nipple that sticks straight up. Could just leave the nipple open. I do. That way you retain the other features of the ACV like the antiafterburn which should help keep the backfiring to a minimum. Or you can do Pacey thing. And yes, as long as you have a vac line going to the boost(pressure sensor), alls well. So, when you get time, what did you do with the airpump? Not a vital question. Just curious. If you take the acv off you should at a minimum remove the air pump belt, but that can lead to other problems like a slipping water pump belt. The airpump belt helps turn the water pump. Still, not a real big deal. It will only happen sometimes, not all the time.

Turtle's TII

My block off plate was not sealing due to it not being cut all the way so it was hanging up and causing a leak.

Trimmed the plate and now it's sealed and idles.

Thank You all for your time.

Pacey3182

I had belt probs when I took my air pump off. A dual belt alternater pully cured it.