85gsl2ndtimearound

So i have been at it for about 12 hours now and i think i need to stop or me, or the car has to die!!!!!

The problems...#1 cant get the car to idel below 1200 a rough 1200 at that #2 when crusing ie. speed limit is 45 and im trying to maintain 49 in 4th the car pulsates for lack of better word and it does so even more at a lower rpm
#3 notices more backfires also ther happing in the cat at least that is where the sound is comming from

new plugs (yes ngk)
newer wires (cleaned all contacts and checked the spark by hooking up old plugs and watching them spark on my feder)
VL you say mabey but i sprayed a whole can of carb cleaner and 1/2 a buttle of propaine around the rats nest and carb

what else should i try !!!!!!!!!

SSRx7

read my post in your other thread... hope it helps. sounds alot like what mine was doing.

Later,
Bill

cdrad51

rough idle, backfires = check your leading ignition, make sure you get spark, if no spark, check ignitors, cables, coils.

Kentetsu

Vacuum leak somewhere.....

NewRXr

Check and confirm proper operation of the Air Control Valve and check valves. I had these problems for over a year and that's what it was. If you have this problem you have a large vacuum leak that is varialble dependant on ACV position and pressure fed by the Air Pump so the higher the RPM the worse it got.

Vernon

85gsl2ndtimearound

changed fuel filter this morning and NO help. Went through a whole bottle of carb cleaner again could not find the VL ?? I guess ill wait for the pros Carl Sterling where are you. One last thing shutter valve has ben blocked for 2 years now.

SSRx7

Ok, I was wrong. Now you got me curious. You said it started suddenly, or has it slowly started acting up the last few days, or weeks? Is it only at certain rpm/ speed/ gear or does it do it at the same rpm in any gear etc, etc?? Narrow down as to the driving conditions that it happens. One other thing that I can think of is that one of the floats may have started leaking, become fuil logged( unable to float) and is holding the valve open that lets fuel into the bowl on the carb. Under hard acceleration, you engine uses all the fuel it can, so it would not be AS noticiable, but when cruising, starts flooding out the engine.

My coworker use to be the rotary guy at the local Mazda dealer, and he is the one I turn to on all things rotary. He was telling me a while back that the floats on these things do leak occasionally.

Just another thing to try. Hope it may help.
Later,
Bill.

SSRx7

Just re-read your first post above, and noticed that you said that the backfires sound like they are coming from the cats. To me that would indicate a lean misfire, because usually, timing problems cause backfires through the carb.

Check the egr valve operation. also check the air control valve and related hoses for leaks. I once found one of the large hoses on mine laying down by the exhaust and had a hole burnt through it. I could never hear the air leak down there and found it by spraying brake cleaner on all the vaccume hoses until I eventually found it.

I confess that I am not a "rotary expert" but all internal combustion engines run on the same principles, therefore, the same set of rules regarding air, fuel and combustion apply. Also, I'm just passing along what has happened too me.
I hope that all the things that have been posted by everyone here will lead you in the right direction.

If all else fails, process of elimination almost always works.

Later,
Bill

inittab

It sounds like the symptoms of a burned up anti-afterburn hose. It's on the passenger side of the engine bay near the firewall and exhaust. http://www.mazdatrix.com/c-5.htm

85gsl2ndtimearound

Thanks but took it off and no cracks or holes shot, compressed air through it no leaks?

85gsl2ndtimearound

could the valve be bad?

85gsl2ndtimearound

Just got back from my mechanic, I am getting ample spark trailing & leading, we also checked compression w/ a non rotary tester and 3 pulses were shown and heard. I dont know whayt it could be? once again please help PLEASE.

Kentetsu

Vacuum leaks can be very hard to detect. One method that might help is to take a long piece of hose (even garden hose will work) and hold one end up to your ear while you move the other end around the engine. This works just like a stethoscope.

The other option is to go down to Autozone and pick up a pack of assorted vacuum lines that are colored (this helps to make sure that you don't miss any, and makes the engine look pretty too). Start replacing them one by one. After twenty some years, she's due for new lines anyway... Cost should be under twenty bucks.