1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

12 A problem

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Old Feb 23, 2008 | 10:13 AM
  #1  
mihu's Avatar
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Lightbulb 12 A problem

Heloo to all, I have a 1985 Rx-7 with the small 12A engine, please help me.

The won't start. The ignition is ok.
I quess the engine is finished.
I measured the compresion and the readings are around 3 bars on each of the rotors.

Can anybody tell me if the engine could start with such readings of the compresion?

One more thing after I crank the engine, the spark plugs are fouled in oil and gasoline. If I crank the engine without gasoline the spark plugs are fouled only in oil.

Please excuse my poor english, I'm a beginer.
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Old Feb 23, 2008 | 10:31 AM
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3 bars?? What did you use to measure compression?

If the plugs are fouled check to see if your getting spark from the coils.
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Old Feb 23, 2008 | 11:06 AM
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Bar is a unit of measuring pressure.

1 bar =14.50 psi

So 3 x 14.50 = 43.50psi.

43.50 psi is extremely low compression.

The combination of low compression and oil in your combustion chamber sounds like your engine is toast.

Last edited by '84-12A-GSL; Feb 23, 2008 at 11:11 AM.
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Old Feb 23, 2008 | 11:21 AM
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is he using a rotary tester?
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Old Feb 23, 2008 | 11:22 AM
  #5  
mihu's Avatar
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Originally Posted by Vashner
3 bars?? What did you use to measure compression?

If the plugs are fouled check to see if your getting spark from the coils.
I measured the compresion with a device similar to this http://cache.jalopnik.com/assets/res...6/compt_05.jpg

10x for the reply.

I measured the compresion in the following way:
-the carburetor was removeded from the intake manifold(not necesary, you cand just keep the throtle body fully open);
-I removed the leading spark plug on each rotor and replaced it with the compresion tester device;
-I turned the key to start the engine, and kept it on until the value on the device reached a peak and stayed there.
The compresion was measured with the engine cold, since I wasn't able to start it. Is that an "isue" in the corect measuring of the compresion?
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Old Feb 24, 2008 | 11:49 AM
  #6  
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You can't use a standard piston engine tester on a rotary because there's a one way valve in the ordinary teter and you need to see all 3 readings as the rotor turns. The one way valve will only let you see the highest reading. Also, if the tester has a long pointed end and sticks into the engine, it is possible to break the tip seals.
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Old Feb 24, 2008 | 01:36 PM
  #7  
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From: alabamer
Assuming the engine was running before, it is likely your chambers have moisture or excessive oil (from oil metering pump) in them. Black oily plugs are fouled plugs, red plugs mean fuel starvation. Tan plugs are happy plugs.

1..forget about using a standard compression gage on a rotary
2..instead, remove plugs, attach them to ignition wires, ground them against the body
3..remove fuel pump fuse
4..open throttle
5..turn engine over, and listen for the swooshes.....if a rotor is bad, you can hear it, and feel it by placing you hand near spark plug hole
6..also check ignition by checking for spark plug's sparking
7..pour and 1/4 cup or about 25 ml 100% methanol (dry gas) down carburator, this will wash out an moisture or excessive oil in rotor's chamber
8.. spray wd-40 on plugs to clean them.....wd-40 is super flammable
9..reinstall plugs , fuel pump fuse, and attach ignition wires
10..try starting

11..send payment to my PayPal account.
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Old Feb 24, 2008 | 02:07 PM
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Blown oil seal?
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Old Feb 24, 2008 | 05:16 PM
  #9  
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Flooded...
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