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

i blew my motor.

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Old May 21, 2007 | 05:54 PM
  #1  
xfillthy's Avatar
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Freezing cold a/c
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i blew my motor.

on my way home last night my temp rose above 100 and the car overheated. someone had mixmatched the map sensor cables and when you try to start it you can hear the rotor hitting the housing.

pretty fucked but a lesson learned.
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Old May 21, 2007 | 06:10 PM
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87 t-66's Avatar
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"mixmatched the map sensor cables"

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Old May 21, 2007 | 06:15 PM
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Uhh...^

Welcome to the club (of blown motors).



James

Last edited by spot_skater; May 21, 2007 at 06:21 PM.
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Old May 21, 2007 | 06:19 PM
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Sorry, but nothing in your post makes sense.
First of all, 100 degrees F (which I assume you are using since you are in Cali) is well below operating temps.
Second, there is no MAP sensor on the car.
Third, assuming you are talking about the AFM, there are no wires to "mixmatch". It is a plug. If its plugged in the car works, if not it doesn't.
Fourth, there is not a way the rotor can hit the housings unless the e-shaft snapped or something, which isn't really possible.

So will the car start? If so, how does it run? I suggest you do a compression check.
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Old May 21, 2007 | 06:25 PM
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xfillthy's Avatar
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i run haltech and there is a cable from the intake manifold that runs through the chassis thats the map sesnsor cable. somone connected that to the blow off valve.
and it spun a bearing
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Old May 21, 2007 | 06:27 PM
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From: PHL
temp rose above 100

I'd love to get those temps!
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Old May 21, 2007 | 06:28 PM
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Do you mean a vacuum hose?
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Old May 21, 2007 | 06:36 PM
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Ah, ok, now it makes more sense. No idea you had a haltech. Anyway, thats weird it spun a bearing. I don't recall hearing of that before on a rotary.
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Old May 21, 2007 | 07:10 PM
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I think he meant 100C. Which is pretty hot since normal operating temp is around 190F or 86 C
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Old May 21, 2007 | 07:13 PM
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welcome to the blown engine club...im 4 months in and falling into depression
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Old May 21, 2007 | 07:15 PM
  #11  
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What a labor of love it is to have a 7
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Old May 21, 2007 | 07:38 PM
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welcome. i love it when i get to rebuild my motor. im still not buying the rotor crash into housing because of a spun bearing. it would if you broke a gear tooth on the stationary gear but that only happens at high rpm.
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Old May 21, 2007 | 07:45 PM
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The rotor may be slopping back and forth and hitting the cast irons, that can happen with a spun bearing. But no way is it hitting the rotor housing. That is quite strange that you spun a bearing due to overheating. If this had been on a microtech, it would have just richened the maps and it would have been fine (though it would have ran like poop). I am also in the club of loving to have a reason to rebuild the rotary. Pitty it is just as summer is starting. Cheers with that.


edit, if it was hooked to the BOV, than it was not BOV'ing right... all kinds of crazy here. You did not notice nothing strange about how it was running? Running badly, no BOV woosh, temp.

Last edited by Radial GT; May 21, 2007 at 07:47 PM. Reason: WOW'd
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Old May 21, 2007 | 07:53 PM
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Originally Posted by stevensimon
welcome. i love it when i get to rebuild my motor. im still not buying the rotor crash into housing because of a spun bearing. it would if you broke a gear tooth on the stationary gear but that only happens at high rpm.
Couldn't a spun bearing, in theory, cause the SIDES of the rotor to scrape against the plates? I doubt he means the apex edge and the rotor housing.

I might be a complete *******, but.... shouldn't somebody with a haltech...... nevermind....
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Old May 21, 2007 | 07:53 PM
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Originally Posted by rx7 FC TII
welcome to the blown engine club...im 4 months in and falling into depression
me too.
it's about 6 months now.
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Old May 21, 2007 | 07:55 PM
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I'm ten months...
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Old May 21, 2007 | 08:12 PM
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Originally Posted by micaheli
Couldn't a spun bearing, in theory, cause the SIDES of the rotor to scrape against the plates? I doubt he means the apex edge and the rotor housing.

I am a complete *******...... nevermind....

yes it could cause the sides to scrape plates.. but he didnt say plates or irons, he said housings.
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Old May 21, 2007 | 09:31 PM
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Originally Posted by MaczPayne
I think he meant 100C. Which is pretty hot since normal operating temp is around 190F or 86 C
100C is about 212F, which isn't particularly very hot.
The motor should handle temps intermittently above 230F or so...105C?


-Ted
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Old May 21, 2007 | 09:52 PM
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Originally Posted by stevensimon
yes it could cause the sides to scrape plates.. but he didnt say plates or irons, he said housings.
Yes, but technically "plates" and "irons" are housings, at least according to Mazda.

An yeah, even 100 C isn't terribly hot. While it could possibly do damage, I doubt it would spin a bearing. I maxed out my temp gauge on my s4. It cooked the already dead coolant seals, but it didn't do anything else.
Also, try being down for 20 months with a blown engine.
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Old May 21, 2007 | 11:14 PM
  #20  
xfillthy's Avatar
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Freezing cold a/c
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i dont know man but the engine is fucked and it ran pretty normal other than the fact that on the trip home it was 100c steady until my friend pointed it out we started to decelerate and the temp got up to 120 after i had turned the car off. cranked it and it sounded like someone was knocking on the door inside the motor.
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