Zero Compression
 

i went to start up the seven today and it turned over like it had absolutely no compression at all. the exhaust smelled like gas really badly. does anyone have any ideas?? thanks alot for your help in advance

Need more info. Has the car been driven daily, or has it been sitting?

it's probably flooded.

Try the different unflooding procedures.

Hugues -

yeah its been sitting for about a week. when i get home today ill try pullin the fuses but how could it cause no compression??? thanks for the quick replies

The only reason I asked, was that if they sit in cold weather, the seals will shrink, therefore no compression.
I don't use my car in the winter, and I've been caught 4 times ('89TII) since new.
Not knowing where you are located, just try the unflood procedure, but if truly no compression, and seals shrunk...It's time for ATF.

When engine is flooded, you lose compression because the fuel washes out the oil that seals the chambers. On a newer engine, it's not as much as a problem as it is on an older engine.

The loss of compression gets worse as the engine is cranked since the injectors are injecting upon startup.

So, the more you crank, the worst it gets.

If the "pull the fuse" thing does not work,
you can do the more involved procedure:

- remove fuse
- remove spark plugs
- crank engine, pedal to floor [to expel the fuel]
- put some oil in the plug oils
- crank engine, pedal to floor [to reseal the chambers]
- put back spark plugs (after cleaning them)
- put fuse back
- crank engine and be ready to catch the engine as it fires (otherwise you'll have to do it again)

Note: some pple prefer to use ATF, I prefer using regular motor oil since it is thicker and more readily available.

Hugues -

One last reply-If seals shrink in cold weather, you'll flood the engine because there is no compression. It works both ways.
You know immediately. As soon as you try & start it, the engine just free wheels immediately-no compression.

What are you talking about "seals shrink in cold weather and cause flooding"? Perhaps you are unaware of this, but all the seals have springs that hold them firmly in place. In fact, the car is much less likely to flood in cold weather than it is in hot weather. I drive RX-7s year around (in Canadian winters) and have NEVER had a cold flooding problem. My flooding problems happen in the summer (search for why).

The reason flooding causes no compression is because it washes the oil film from the rotor housings, this preventing the apex seals from sealing.

would that also mean that I got leaky injectors??

by the way thanks guys for helping me I REALLY appreciate it. This forum ROCKS!!!!

Aaron:
If car sits in back garage for more than @ 2 weeks without starting, I might as well let it sit all winter and do the ATF in the spring. As soon as you engage the starter, the engine just free wheels. No trying to start, no compression, no flooding at first.. The first time it happened it was towed to Mazda in 1992. From that time it's got me 3 times. Take one of the cars and let it sit for 2/3 weeks in 20 degree temps, then try and start it. There is no flooding, immediate zero compression. If you use it everyday, or once a week no problem.
Maybe you can explain zero compression without first flooding.

Your car has a problem then. Perhaps leaking (dripping) primary injectors. If the car sits long enough, the residual fuel pressure bleeds out through the primaries, thus flooding the engine.

To put this into perspective, I just started up my winter beater '78/'79 1st gen last week for the 1st time in 6 months. Fired up on the first turn of the key without using any ATF of oil (though I did fog the engine first). And that was on 6 month old gas.

Flooding causes zero compression because it washes the oil from the rotor housings and prevents a good seal. I said this in my first post. But letting the car sit and/or cold weather does not directly cause flooding.

Aaron:
Thanks for the reply, but I purchased my '89TII new in march '89. Just had an engine installed 156,000miles Aug. this year. It may be hard to believe, but the car has never flooded winter or summer. I can drive with air on, shut it off in hot humid weather, and it starts right up. Believe me, I'm not knit picking, but if the seals have springs, why wouldn't they seal even if there was no oil. Also, if flooded, you can crank the engine without plugs, replace plugs and it will sometimes start without the atf trick, and at that time there would be no oil on the seals on account of all the gas that has flooded chambers.
Just trying to understand why they won't start after sitting in cold weather. I've gone through this for 12 years. And I'm not the only one. The first time in '92, the dealer had 4 that week that had sat idle all winter and wouldn't start in the spring. T
Thanks

ill give everyone an update tomorrow. Do you guys think this should be archived for future reference??

yea it prob should never know when someone else will need this!!

ok the engine runs now but it seems like it is a little rough but it revs fine and everything else. there is a metallic clicking sound on the passenger side of the engine does anyone have any clues again??

just to let people know...aaron does know what he is talking about...not that everyone doesnt..but he knows his stuff

anyone??

great now that clicking turned into a constant squeal com'on somebody im in dire need here!!!!!!!! thanks in advance