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Bought a used RX8, Did I Blow the Engine?

Old Aug 28, 2019 | 06:06 PM
  #51  
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That plug looks good. Not even that used.
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Old Aug 28, 2019 | 06:14 PM
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Theres weird silverish putty on thus one, its a trailing
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Old Aug 28, 2019 | 06:17 PM
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Old Aug 28, 2019 | 06:20 PM
  #54  
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Probably anti-seize compound.
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Old Aug 28, 2019 | 06:21 PM
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The silver stuff looks like anti seize. If the plugs were installed right after the rebuild, then the rebuild is recent. Those plugs have hardly 1k on them.
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Old Aug 28, 2019 | 06:22 PM
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Thank you!
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Old Aug 28, 2019 | 06:29 PM
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Ot

Other leading plug,,, you say about only 1k on them?
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Old Aug 28, 2019 | 06:32 PM
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Yeah they are young. With time they build up a crust.
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Old Aug 28, 2019 | 06:37 PM
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So then what next,, converter? Or how do I test coils
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Old Aug 28, 2019 | 06:54 PM
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Last plug looks the same,, theres some oil on the bottom of the oil pan, I overfilled the oil I think but dont know if that would have anything to do with it,, and there oil pressure guage has been fine,, it looks like small amounts may have leaked from the bolt but idk
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Old Aug 28, 2019 | 06:56 PM
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Decided to drain it and do an oil swap
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Old Aug 28, 2019 | 08:01 PM
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Check that cat before driving the car more, They can clog a little and give you less power and clog a lot and kill the engine because it can't breath. I've almost burnt my car to the ground with one.
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Old Aug 28, 2019 | 08:05 PM
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Ah! Overfilling the oil sometimes makes the engine burp oil into the intake, dirtying the MAF and sometimes causing idle or driveability problems. Not exactlt like your no-start. Wouldn't be a bad time to check for oil in the intake.

Testing the coils: you can get a simple clip on spark tester that allows spark plugs to fire outside the engine. It'll allow you to see the spark. If you're handy with a multimeter there are electronic tests as well, but you'll have to google those.
Given that the plugs are recent, perhaps the previous owner was wise enough to change the coils at the same time.

As far as next steps, yeah having a look inside the cat is probably best, and compression test. You're looking for the honeycomb or spiral element to appear clogged, broken or sitting cockeyed in the cat.

So we've established you're not burning coolant and the spark plugs are in good condition and appear to be sparking. And the engine isn't flooded. That eliminates a bunch of possible problems.

When you change the oil, look for metallic shimmer on the used oil. The rattling sounds you describe are probably not bearings, but its good to check.
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Old Aug 28, 2019 | 08:40 PM
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So if not converter then compression?
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Old Aug 28, 2019 | 09:16 PM
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Originally Posted by BenG
So if not converter then compression?
One thing at a time. A compression test is never a bad idea regardless of the symptoms, so you know where you stand.
The cat isn't preventinf you from starting, but if has been damaged for a while, it could have caused you to lose compression amd the symptoms you're experiencing.

So if you prefer, comp test first. If it's fine then we need to look at starting speed, electrical connections etc. But that's hard stuff to nail down.
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Old Aug 28, 2019 | 10:54 PM
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So I took the cat off and its already been gutted, so that explains cel,,, but that doesnt explain the no start issue :/ so what next
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Old Aug 29, 2019 | 05:29 AM
  #67  
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Possibly the starter?, it looks rather old
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Old Aug 29, 2019 | 06:04 AM
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I agree with Loki - the cat was gutted (for whatever reason) so I would recommend to determine the health of the engine though a rotary-specific compression test. You may find someone near you that has one and can help you with the diagnosis - post your need on the regional-specific forum on RX8club.com (example if you live in Greensboro, NC there are 2 people with CTs that I know).
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Old Aug 29, 2019 | 09:10 AM
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Before spending any more money you should still ensure you are making good compression and can pass a block test. Otherwise you are throwing your money at what will be an expensive time bomb.
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Old Aug 29, 2019 | 12:49 PM
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Can a normal shop do the test? And how much
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Old Aug 29, 2019 | 01:03 PM
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Originally Posted by BenG
Can a normal shop do the test? And how much
The block test any shop can do but the compression test requires a rotary compression tester. Just bring it into Mazda or just buy the tester yourself. Www.rotarycompressiontester.com
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Old Aug 29, 2019 | 01:10 PM
  #72  
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Mazda is like 3hrs away from me :/, and I cant afford the tester ha,, Ive seen videos of it done with a normal pressure tester, so thats not possible? And what will the block test tell me
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Old Aug 29, 2019 | 01:18 PM
  #73  
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You can try testing with a regular tester and a camera, in a pinch. It's not super precise, but it's good for confirming major compression loss. It's not great though. If it gives you a borderline result you may want to confirm it with with a real tester.
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Old Aug 29, 2019 | 01:23 PM
  #74  
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I was literally in your shoes 4 years ago when I bought my 8. You can look back at my threads and check it out for yourself. Same symptoms and all. I would listen to these guys and just get the info or test that they are requesting.
I will say it sounds like your gonna need a rebuild as I did also.
And the more miles you squeeze out of it. Will just end in more things being replaced internally or kill some other external components of the engine.


I'm sorry
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Old Aug 29, 2019 | 02:41 PM
  #75  
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Originally Posted by BenG
Mazda is like 3hrs away from me :/, and I cant afford the tester ha,, Ive seen videos of it done with a normal pressure tester, so thats not possible? And what will the block test tell me
It's good only just to confirm if there is major compression loss. Driven by Madness on youtube has a very detailed guide on how to do it. Wont be as accurate as the proper tester but it's better than not testing it at all. The block test will test to see if the engine coolant seals are still intact. If those seals go the engine itself wont be far behind.
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