2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

full boost = going no where?

Old Nov 26, 2002 | 01:12 PM
  #26  
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First let me say that yes comp. test is the first rule of rotary troubleshooting, and yes you should probably do it anyway for the hell of it, but that probably ISNT the problem. I know your rebuild isnt even 1.5 years old IIRC and I dont see it going out unless you did something dumb.

Next, he was just saying 15psi as a comparison, meaning that at 0 boost or full boost it feels weak. Doesnt mean he actually ran it at 15psi, he said he ran it at 12, which is borderline ok for stock IC and fuel.

IF it were me, I would pull my exhaust OFF and go for a quick run, just to eliminate that. WIth a modified exhaust a big restriction is doubtful, but you never know, and its easy to do.

ALso let it be noted that the 680's without a controller will LOSE you a bit of power, though it could be considered a safety mod and thus isnt all bad. I have done this personally, and yes it'll run and drive fine, but you WILL have a stumble and power loss between 3 and 4500 if you cant turn 'em down.

Next the oil deposits int he secondary intake runners is normal. Every rotary Ive looked in had that, and though people's opinion of what it comes from varies, its nothing out of the ordinary.

However the smoking is not normal if it is that bad. It could be the turbo itself, or it could be internal. Not a real good way to tell since the turbo can shoot oil out the exhaust only, or out the intake and exhaust, in which case you can find it in you intake path. You might try another known working turbo, or even pulling yours and runnign the car to see if it still smokes. Be sure to reroute your water and oil lines back into their respective drains before trying this. It'll be loud as a ****, but you can let it run adn see if it still smokes without the turbo in the loop.

You could also have a boost leak somewhere, so check your hoses and **** and IC for leaks.

Im assuming your ignition is good, as that seems to have been covered, check your timing though.
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Old Nov 26, 2002 | 08:54 PM
  #27  
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well i did a comp test like everyone wants it came out 90psi on the front and 20 on the rear, keep in mind done with a piston compresson checker with the check value in. Now, knowing that I still dont understand this. the car will run, if the compression was truely bad shouldn't it have trouble idleing or give a big fuss trying to start? I can't believe that this engine has gone bad, it only has 10k on it and i've been babbying the crap out of it. WTF! I'm got some atf in it right now to see if maybe its just a stuck seal, I'll got start in on thursday so it has a full day to soak and then test it again. My motor was freshly built can i just replace the seals and make everything all better?
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Old Nov 26, 2002 | 09:12 PM
  #28  
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From: usa
Well, that sucks. Dont really see how that happened.

However, trust the results since you used the same tester. IF the number for the front is semi-accurate then the number for the rear shoud be very similar as well.

This is to say that the actual *number* you got may not be accurate, however the *difference* between the 2 chambers is accurate since you used the same testing method and devide on both.

Guess those 680's arent as much as a safety margin as I may have thought

Let me know if you want help diagnosing it or getting it back right. Depending on internal damage we might be able to do a partial rebuild for under $1000.
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Old Nov 26, 2002 | 09:42 PM
  #29  
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Originally posted by jacobcartmill
are you sure that you have good compression on your rear rotor? it sounds like the compression was low and it finally gave out. just a thought... it seems like you're checked everything else. the only other thing i could think of is a very very restricted exhaust, like a clogged cat, but you say you checked that.
the reason i think you could have low compression on atleast one rotor is because you were running 15 lbs of boost...
i was right!
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Old Nov 26, 2002 | 10:20 PM
  #30  
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Originally posted by jacobcartmill


i was right!
I was right first
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Old Nov 27, 2002 | 12:39 AM
  #31  
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damn
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Old Nov 27, 2002 | 12:43 AM
  #32  
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hey guys, i was thinking about renting/borrowing a compression tester. where can i get one? i was thinking about checking my compression even though the motor feels pretty strong... you never know. any places other than the mazda dealer to get one?
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