Low compression on a motor
12-28-2014, 09:38 AM
#27
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yes, I think it is because of a remote start. Because it never starts my car from the first try, it takes 2-3 times for it to start through a remote start. So I am pretty sure that it had something to do with a remote start. Thank you for all your help. I am very happy that my car is finally back on a road
12-28-2014, 10:15 AM
#28
Driving my unreliable rx8
Im glad you got it running again too.
And thank you for putting the results up. Too many people fix stuff and never post it so you have threads with no end result.
And thank you for putting the results up. Too many people fix stuff and never post it so you have threads with no end result.
01-05-2015, 10:51 AM
#31
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There are very very few "rotary mechanics" in the US. The closest one to NYC is in NJ I believe, JPR Imports?
If all you need is a compression test though, just go to a dealer, they will be closer.
If all you need is a compression test though, just go to a dealer, they will be closer.
01-07-2015, 04:38 PM
#32
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My Mazda dealership recently mis-diagnosed my car stalling as a compression issue and told me I needed to replace the engine. It turned out that the computer had lost the fuel trim levels since the battery had been disconnected. It drove fine the next time I started it and has ever since.
My point is that even the certified supposed RX-8 specialists jump to conclusions like this.
My point is that even the certified supposed RX-8 specialists jump to conclusions like this.
01-09-2015, 12:59 PM
#33
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Okay, so I got my compression test done. Here are the numbers
The first row is for front rotor and second for rear
The first row is for front rotor and second for rear
Last edited by QuiQuik2003; 01-09-2015 at 05:00 PM.
01-09-2015, 08:06 PM
#34
Okay, so I got my compression test done. Here are the numbers
Attachment 207514
The first row is for front rotor and second for rear
Attachment 207514
The first row is for front rotor and second for rear
well, I guess by the time summer comes, I'll have to get a new engine....
01-13-2015, 01:01 PM
#38
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I was looking around trying to find out when engines actually "fail" as opposed to "fail to meet Mazda specs". Some people are saying they still drive theirs with numbers in the 4's. Does anyone know roughly how low it gets before the engine stops starting? Or stops starting when hot?
I guess it depends on air temperature and altitude and stuff too but I was just wondering. Also I'm sure it affects the horsepower but I couldn't find any numbers on that either.
I guess it depends on air temperature and altitude and stuff too but I was just wondering. Also I'm sure it affects the horsepower but I couldn't find any numbers on that either.
01-13-2015, 01:12 PM
#39
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Too many factors to just throw out one number.
Plenty of people have driven the engine without any seals at all, which would score 0.0s across the board on a compression test. Granted, it's insanely hard to start and the revs have to be kept really high, but it's possible. I watched another member set their bumper on fire from keeping the revs over 8,000rpm to keep the engine alive.
Plenty of people have driven the engine without any seals at all, which would score 0.0s across the board on a compression test. Granted, it's insanely hard to start and the revs have to be kept really high, but it's possible. I watched another member set their bumper on fire from keeping the revs over 8,000rpm to keep the engine alive.
01-14-2015, 10:41 AM
#40
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Wow, that sounds...awesome? It wouldn't really be 0.0 though, right? I mean doesn't there have to be some compression to ignite?
At any rate, my point was that if QuiQuick2003 is in the 5.8-6.8 range he probably doesn't need to be panicky about getting a new engine this summer, right? Or do they drop that quickly?
At any rate, my point was that if QuiQuick2003 is in the 5.8-6.8 range he probably doesn't need to be panicky about getting a new engine this summer, right? Or do they drop that quickly?
01-14-2015, 10:49 AM
#41
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Yes, you need compression to produce the necessary combustion. The rotary makes more compression the faster it spins, so what I meant was that at the testing rpm of ~200-300rpm, it would be 0.0. At 8,000rpm, it's generating enough compression to get the combustion, probably in the 4s or 5s.
This is one of the reasons why low compression engines usually still "feel fine" and it surprises owners.
In the 5s though, he doesn't have long before it is terminally unable to start without extra-ordinary measures. Probably less than 5,000 miles. Blowby is accelerating the rate of compression loss, eating away the seals faster and faster.
This is one of the reasons why low compression engines usually still "feel fine" and it surprises owners.
In the 5s though, he doesn't have long before it is terminally unable to start without extra-ordinary measures. Probably less than 5,000 miles. Blowby is accelerating the rate of compression loss, eating away the seals faster and faster.
01-15-2015, 06:46 AM
#42
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But it wouldn't just stop starting one day. Would it? It'll take longer and longer for it to start. Right? I'm going back to JPR in about a month to see if the numbers keep dropping. Im still hoping it is recovering from that major flood that it went through recently. I know that wishing for numbers to go up is just wishing. But maybe they'll just stay the same.
01-15-2015, 08:28 AM
#44
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Yea well it's on original engine and it has 88k miles on it so it's not too bad. Maybe before it stops I can get it to 100 k. My boyfriend also suggested to put a mustang v8 engine in it. I did some research and it doesn't seem that anyone was actually successful at putting a new engine in or maybe just never posted the results. But I also love rotary so I really want to stick with the original engine. Maybe just turbo charge it for higher hp. That's the reason why I got this car. It's just so unique and so different and Im not about to just give it up. And I knew what I was getting into when I got this car. So Im sticking with the rotary.
01-15-2015, 11:36 AM
#45
Yea well it's on original engine and it has 88k miles on it so it's not too bad. Maybe before it stops I can get it to 100 k. My boyfriend also suggested to put a mustang v8 engine in it. I did some research and it doesn't seem that anyone was actually successful at putting a new engine in or maybe just never posted the results. But I also love rotary so I really want to stick with the original engine. Maybe just turbo charge it for higher hp. That's the reason why I got this car. It's just so unique and so different and Im not about to just give it up. And I knew what I was getting into when I got this car. So Im sticking with the rotary.
Some people call it quits when stuff like this happens. You have a bit of reading to do if you replace the engine with another Renesis (which is probably faster/safer/easier than other options). Things like where to get your rebuild and what to look out for when it's put in. There were mentions on the forum of Mazda re-manufactured engines shedding bits of silicone sealant into the cooling system, for one.
01-15-2015, 11:54 AM
#46
You gonna eat that?
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Hi, sorry to hear about your 8.
You can maybe try a de-carbon (sometimes called Zoom cleaning, Seafoaming) process. You might want to research it, it might buy you some time, unless someone thinks it's not a good idea.
You can maybe try a de-carbon (sometimes called Zoom cleaning, Seafoaming) process. You might want to research it, it might buy you some time, unless someone thinks it's not a good idea.
01-15-2015, 06:32 PM
#47
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yes, I do plan on doing seafoam this week. Friday or saturday. Also gotta do some research on how to do it properly cause different people say different stuff. So I'll do some research of my own on a forum.
01-15-2015, 06:36 PM
#48
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That's the spirit! Some people call it quits when stuff like this happens. You have a bit of reading to do if you replace the engine with another Renesis (which is probably faster/safer/easier than other options). Things like where to get your rebuild and what to look out for when it's put in. There were mentions on the forum of Mazda re-manufactured engines shedding bits of silicone sealant into the cooling system, for one.
Some people call it quits when stuff like this happens. You have a bit of reading to do if you replace the engine with another Renesis (which is probably faster/safer/easier than other options). Things like where to get your rebuild and what to look out for when it's put in. There were mentions on the forum of Mazda re-manufactured engines shedding bits of silicone sealant into the cooling system, for one.
01-15-2015, 08:22 PM
#49
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Plenty of arguing throughout the thread, but unbiased pics of before and after decarbing with various common methods to just see what actually happens inside the engine.
01-15-2015, 08:59 PM
#50
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Read this full thread before you do anything, and decide for yourself: https://www.rx8club.com/series-i-tec...r-pics-241867/ Plenty of arguing throughout the thread, but unbiased pics of before and after decarbing with various common methods to just see what actually happens inside the engine.