ok well, as some of you know my uim cracked last night.....
so today i replaced it.... anywho ..
when i started it up, there was some smoke.. ofcourse from the coolant that leaked out last night. .... but there was A LOT of hot air blowing out of the intake from somewhere, im not sure where it was from yet, but it seemed like it was coming from the lower intake, or possibly the EGR, but.. i dunno theres something going on here i cant figure out ... anyone have any thoughts?

 

were you the one who said they lost their EGR? if you don't have one you did block off the ports correct?

 

How do you crack an UIM?

 

He told me on aim he statred it one night and coolent just sent everywhere, i dont think even him knows how it broke

 

I'm still lost.... the UIM is pretty thick metal. I gotta see pictures of this.

 

I asked the EXACT same question in his other thread. I told him to post pics. If he doesn't post pics, we can't help him.

I removed the EGR before I really understood it. There is a valve on the top of the intermediate housing that closes and opens. When its open, it allows exhaust gas from the combustion rotation enter a port that is right beside the valve, underneath it. This port leads to the intake manifold, through a seperate jacket OTHER than the intake. This jacket travels UP to the center of the lower intake manifold to a valve that is behind the Air control valve. This valve opens, and vents the exhaust gas, to, well thats as far as I know. Like I said, I never fully understood it, I just removed emissions and said **** it.
ANYWAYS, isn't EGR gas supposed to go into the intake during idle? I thought that was totally normal? or is it when the engine is in the upper rpm?

 

EGR passes innert gasses into the intake during cruise, innert gasses(exhaust) merely displace some of the intake charge going into the engine to lower combustion temperatures and therefore lower NOx output from the emissions of the engine.

NOx is a poisonous gas to humans.

 

well, i put my egr back on and everything before i tried to start it last night..... the only thing i cant figure out is why there's hot air coming from the intake manifold, it might be where the LIM bolts to the engine.... which could only mean one thing... that the LIM has cracked as well.... the UIM cracked simply because i over tightened one of the bolts... stupid yes, the stud came out with the nut so, i used a different one and had to tighten it down like a mother $%^$%^% just to get it to stay down, so inturn, that section of the UIM cracked, but it's really not even a bad crack, could be welded and fixed up just fine, and FYI:
the UIM may be thick metal but, its aluminum... no matter how thick it is, stupid mistakes like over tightening WILL make it crack, there is a reason the FSM says to only tighten it 14-19# ...

anywho, if anyone could please PLEASE help me figure out what could be leaking from the LIM i would be so thankful, it's an audible sound, it's very loud, wooshing sound, but... it's blowing air OUT which is the strange thing, it seems to be right where it makes to the block...

 

bumb = it's light out again, need to get to work on the car... and i take you people's advice over most things, so any input would be great

thanks,
alan

 

Get a copy of the service manual or Haynes manual. Find everything that has to do with the secondary air injection system, and the EGR circuit. Follow the paths of both circuits and look for your leak.

EGR valves aren't really necessary on the rotary, and Mazda killed them for 89+ 2nd gens. The long "chamber" shape and intake/exhaust overlap on the rotary creates a "natural EGR".

 

I have mine disabled by blocking off the vac. line that runs to it, but would like to remove it next time I get the time to pull the UIM off again. Can you just cut a block-off plate and replace it with that, or is it more complicated since it's re-directing through the housing?

 

Well, the air isnt coming from the EGR... just checked it all out... but the LIM seems to be in good shape, is there any vac lines on the back side of the LIM that i dont see? (the side close to the firewall) because i can feel air coming out when running it, it's coming from somewhere down there next to the LIM... i thought at first it had something to do with the aux. ports... but i dont see how in the hell they could be leaking THAT much, i did just clean them... but damn this is A LOT of air, i can hear it, feel it, smell it.... it's an eye burning air, im just worried that i cracked the LIM as well ....

 

is it the split air pipe from the exhaust? if it is, your car will sound like a nitro R/C car when you rev it up.

 

well, i dont have the split air hooked up, i have the hose coming out of the manifold, but its just hanging there... i couldnt feel any air coming out of it, so i didnt put it back on before i started it up.. but whatever my problem is now with the air, the engine wont idle, i can start it, and hold the idle myself, but if i let it drop, it will instantly die, also everytime i start it, for some reason EVERYTIME it does the AWS start up..

 

3 places that blow air in the engine: exhaust, cooling fan, smog pump.

EGR is related to exhaust so if you checked the EGR you can rule that out. next i would start looking at the air injection system for possible leaks somewhere.