Bought a used RX8, Did I Blow the Engine?
08-28-2019, 06:54 PM
#60
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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
08-28-2019, 08:01 PM
#62
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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.
08-28-2019, 08:05 PM
#63
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.
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.
08-28-2019, 09:16 PM
#65
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.
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.
08-29-2019, 06:04 AM
#68
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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).
08-29-2019, 09:10 AM
#69
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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.
08-29-2019, 01:03 PM
#71
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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
08-29-2019, 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
08-29-2019, 01:18 PM
#73
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.
08-29-2019, 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
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
08-29-2019, 02:41 PM
#75
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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.