RXTbone

I just had my shutter valve go bad. I've done a search and pretty much understand I can either replace it or close it off. A couple of questions I couldn't find the answer to:

Has anyone ever doused it with carb clearner, both on the outside and some down the hose? Is there a remote possibility this will work?

Also, should I decide to close it off - do I end up having to adjust the idle speed?

Thanks!

racermike

Usually the diapham gets a hole, so lubing doesn't help. However it's possible that the plate inside the manifold is stuck. Disconnecting it from the valve will allow you to determine that and possibly free it up. As long as you block ALL hoses, and the mechanics are in the right possition, I think you should not have to adjust idle.

RXTbone

... OK... got a bit of an update and details for any help you guys (and gals) may provide...

So I go home at lunch and call a buddy - tell him I'm getting white smoke when I try and start the car. He goes "uh oh - you've blown a gasket".

I might believe that, but the smoke smelled exhaust, straight up (no sweet smell), and my carb seems to be filling up with excessive gas. Right now I can't seem to get it started... so I'm charging the battery and going back to work.

Am I wrong in that the white could be from the car being flooded? The car runs rough through the entire RPM range. Also, I tried the trick of closing off the hole to the shutter valve via the air cleaner, and that just kills my car.

Am I hosed with a busted gasket? Or are these all symtoms of a shutter valve gone bad? Any thoughts?

Thanks in advance!

RXTbone

One other detail - when the air cleaner is removed - I'm getting white smoke up through the carb...

Thanks for any help...

Rx7carl

Sounds like you flooded it. If you carb barrels are full of gasoline, then your needle valves are stuck. Tap the top of the carb with a screwdriver handle where the fule lines go into the top of the carb. Your smoke is probably the extra gas, so get that fixed first, and un flood it. If you need to bloxck off the shutter, look at the emissions tutorial, theres a section in there on how to handle this.

inittab

I'm not suggesting that this is your problem but does anyone know if shutter valves ever get stuck closed. If that happened the engine would pretty much only run on the front rotor. Just curious.

RXTbone

Thanks - I tried that, to no avail. I do think it's flooded though...

I pulled the plugs, everything seems to be firing OK. The front rotors plugs were covered in gas. I did notice what appears like metal dust in the gas though - that's a little disconcerning...

At this point, I can't get it started - there is gas getting in the carb - so I think the fuel system is OK.

The car was running rough, and I did notice a lack of power. I turned the car over with the plugs out of each housing. The front sprayed gas against the in fender well will some force. The rear seemed dry as hell, and didn't seem to have the pressure the front had. I could be imagining things, but I'm afraid I may have to face facts - I've lost a rotor.

Very weird though - as I mentioned, I'm fairly certain the white smoke was from the car being flooded - and if it was water, wouldn't I be running low in the radiator? I must have driven it for 20 minutes getting home, and lost no water. Could I somehow have lost gas to the rear rotor?

Happy Holidays.

RXTbone

Actually, I had wondered the same thing. Is this possible (or another explaination to my last post).

Thanks everyone!

Rx7carl

I'm sure its possible, but you can manually move the linkage to see if its stuck. Also that would cause low compression on the rear rotor during a test as almost no air can get thru. Last resort could be a ATF/MMO treatment in case you just got stuck seals. But at least try to get it running first.

BrianHeston

The worst thing that I have seen happening with the shutter valve is what happens with ROTORCOASTER's. His is all still hooked up the way it should be, it just has what appears to be very loose linkage, so it just randomly decides to shut on him. Needless to say, this can be very unpleasant. From the sounds of it, lately it has been shut more often than not, so it's more just a thrill when it opens.

Anyway, he doesn't come on here much, but if he does, maybe he'll see this and comment a little. Just thought I'd let you know.

Brian

RXTbone

Well f*&k - no I went a busted a solenoid tip off trying to open the shutter valve.

Time to quit for the day. I'll working under the theory I have a stuck shuttle valve tomorrow...

Hey, BTW, are those six solenoids interchangable?

ROTORCOASTER

Yeh, it is a daily problem, that I need to repare soon.

Rx7carl

Yes all the solenoids are the same AFAIK.

82transam

iTrader: (18)

technically it'd be running on half of the rear rotor cause the shutter valve only coveres one of the two intake runners (whatever they're called) going to the rear rotor. Just a side note about the shutter valve, its totally useless, I had mine plugged and was having problems with inspection, so I unplugged it thinking that was at fault and the emissions got worse. Turns out my cat was bad and replacing that with the shutter valve plugged passed emissions with flying colors. So the shutter valve basically does nothing other than kill the engine slowly.

jayroc

To my knowledge the shutter valve, or coasting valve, causes the RPMs to drop faster by cutting off most of the airflow to the #2 rotor. The valve actuates the primary intake port of R2, so if it's stuck closed and your secondaries aren't opening like they should, then your R2 rotor is running way lean. I think R2 would still get some fuel, though, since there's overlap on the manifold itself on the primary side.
I've messed with trying to change it out. Let me tell you, it's not anywhere near worth it. It's expensive, and a pita. If you want to do the job right, you need the throttle plate, the shaft, the valve and new gasket. The valve itself isn't too bad, but if the throttle plate needs to be replaced, forget it. Too much trouble.
All I would do, if I were you, verify it's not stuck closed and then put a vacuum cap on the vacuum port of the valve, then plug something down the tube for the air cleaner. When I did this, I noticed the RPM falloff on decel was slower.
If you have the money, you might also look into a carb rebuild and removing the rats nest. Sterling or rx7carl reputedly have mad carb skillz. That is of course, presuming your motor isn't blown.
Anyways, good luck, either way.

RXTbone

... I have faith I'm dealing with a carb problem, I certainly don't want to be rebuilding an engine over the holidays...

I'm still haven't figured out why the engine is running rough - it's as if the timing is off. When the shutter valve is actuated, the timing isn't affected is it? I'm guessing the roughness and backfiring is a by product of the flooding...

ray green

iTrader: (14)

Damn that's a pretty 7. Hope you get it fixed!
Ray

bliffle

Nice looking car, RXTbone.

B

RXTbone

Thanks fellas...

... she RAN great, too... !

Happy Holidays!

jayroc

There's a FAQ on the mazdatrix site that explains the shutter valve. If it has a whooping idle, the culprit is likely the shutter valve. You can test by taking off the top of the air filyer box and putting your finger over the hole from the valve that goes into the airbox. If the idle stablizes, then it's the shutter valve. If you follow the hose from the valve you should be able to locate it, but if you can't mazdatrix has the detailed instructions.

RXTbone

... I've tried that. There was plenty of suction, which I understand means it's bad. But then it completely killed the car - so I'm confused.

I think my baby's off to a professional...

inittab

It dies because the idle and mixture screws are adjusted against a faulty shutter valve. I'd start by adjusting the idle up quite a bit then block off the large vac hose to the shutter valve. The idle will drop but it shouldn't die. With the shutter valve disabled now you can adjusted the idle and mixture properly. Make sense?

82transam

iTrader: (18)

yea what inittab said, I had to fiddle with my settings quite a bit after blocking it off to make it work right.

RXTbone

Cool - I'll mess with that before I take it in - like I said, I stopped when I blocked the hose and it died. I'd rather try that before I pay someone to work, though...

Hey, I've PM'd a couple of members about a choke cable and a green solenoid valve I busted in the process of f'ing with the shutter valve - anyone have these two items?

jbcobra

While we are on the topic of shutter valves, I blocked off the vacuum tube on mine a couple of months ago when the valve went bad. This made a huge difference in the idle but my gas mileage has gone to hell. I used to get about 20 mpg and now it's more like 16 mpg. It also seems to be running really rich at start up. Is this normal when the shutter valve has been disabled or should I be looking for other problems. I’m using an after market fuel pump without a regulator so I though I might try a regulator so see if that helps.