Hurt the 13B, but what is the diagnosis?

[TiddlesRX7]

Thing is though, its only worth IF you can get something better for the money, and due to the spec of my car, getting something as quick in a straight line and good handling as mine (in no small part due to the extreme lightness) would be impossible I reckon even if I sold it for more money than I paid for it.
Seems like no matter if I was in to drag racing, drifting, track, whatever, my car, regardless of engine, its the ideal car to base it on, so would need some serious cash or another serious bargain to appear to let it go.

FC\'s FTW!!!!!!!!

[StavFC]

Was about to pull the engine today, but things have got even stranger now...
 
My brother was over from Canada and out of random interest I decided to show him the car was fooked, and oddly, it started!
Sounded lumpy and low, but it started?! Stopped and started it about 10 times and it fired up and idled every time, hot or cold- It would barely start even with a push start before.
 
We did a spark test-
Pull off the leading plug leads and it idles worse, but each rotor sounded the same, like they was running as healthily as each other.
Pulled off the trailing plug leads, and despite them sparking strongly, it had zero effect on idle- Do they do nothing at idle then?
 
The amount of missfire and so on varied randomly as was running too, better and worse, which seemed at odds with mechanical issues too.
 
Pulled off MAP sensor and FPR pipes and that affected idle as expected, so its neither them at fault.
 
The plug leads thing, showing both engines acting identically well/badly, plus the general behaviour of the car when it acting like this, suggests its not the engine now?!
 
Im going to change the fuel filter next and see if that makes any difference, but overall, im confused as fook.
 
BUT if its not mechanical, thats awesome.
 
I jus cant see how it can be mechanical, as the likelyhood of BOTH rotors having exactly the same amount of tip damage as each other that you cannot physically tell one from the other when testing them by pulling plug leads while running, is pretty damn remote, surely?

[ad4m1]

Compression test will tell you once and for all. Where you based?

[turbotoaster]

you really need to get to a proper rotary comp tester just to confirm.
 
the trailings dont really do anything at idle in the scheme of things.
 
Have you driven the car again, like around the block or just had the engine idleing.
 
from your previous explanation it sounded like it had good dynamic compression but crap static comp

[Prof]

trailing plugs \'catch\' the bit of charge that get\'s trapped as the rotor passes the midway point - and helps provide a better burn for emissions.  The engine will run on just the leading plugs with no problems and no appreciable loss of power.
 
Bit of a mystery as to why it\'s running better now.
 
Could a temporary oil shortage cause something like this ?  The oil is used to help build compression, if the premix/oil injectors or eccentric shaft oil jets fail to provide enough lubrication it might have given symptoms like that possibly ?
 
There\'s only one way to know for sure, but a full compression test is cheap enough and will give a good indication of whether you need to pull it apart or not.

[StavFC]

Im based in Cheltenham, Gloucestershire, and I dont want to drive it to our clueless local Mazda garage as they wont know what they are doing.
Really need a rotary comp tester.
 
But either way, for both rotors to sound/idle identical (to all 3 of us, and the other two people were an RAF mechanic and an aerospace engineer) when pulling off 1 leading plug at a time, rings some alarm bells, as for both to be that equally fooked, considering there are 3 tips on each, and the car is good enough to start pretty much first turn hot or cold, seems a bit unlikely.
 
The way the idle got better and worse so suddenly was odd too for a mechanical issue.
 
Its a mystery, but deffo seems like no1 job would be to borrow a rotary comp tester of someone.

[gazzgazz]

speak to Jit on here,
 
he has a genuine mazda tester and dosn\'t charge the earth, he\'s done a couple of cars for me and i\'m sure he wont mind traveling over to you.
 
i dont think anyone will be willing to lend out a compression tester tbh

[RobMatthews]

I never intended to step on someones enthusiasm for wanting to get more hp,im sure you(stav) is a great guy in life only thing that pee\'s me off was the quote

 "so it probably will be the spinning wheels of unreliability once again, lol."

as im always being asked how many miles i get outta my rotarys befor rebuilding them and people honestly believe they are so unreliable! first thing people say is that! and these quotes only add to that internet missinformed jungle out there!

[turbotoaster]

think about it though rob........how many turbo rotary engines make it to 100,000 miles, i cant think of one.
 
The compression ends up to low or most likely the seals fail.
 
Now compare that to most performance piston engines, yes some will blow up but there are alot that will make 100k and still be strong.

[Nik da Greek]

think about it though rob........how many turbo rotary engines make it to 100,000 miles, i cant think of one.
 
The compression ends up to low or most likely the seals fail.
 
Now compare that to most performance piston engines, yes some will blow up but there are alot that will make 100k and still be strong.

Meaningless comparison in the extreme. Why not compare rather more like for like and say "how many 1.3 litre piston engines put out between 250 and ~400 bhp and reliably make it even as far as 60 000 miles?". Then it may be worth wasting time typing out the question.....

[turbotoaster]

well there you go, thats the issue right there.
 
People dont look at the engine size, they just know it as a rotary engine.
 
Or the people that think they know something call it a 2.6litre.
 
If we ignore the capacity.....alot will compare it to cars in its class........200sx, cossie, evo, scooby....a cheap turbo car, they see all these engine builds or problems and assume people in other cars dont always have these issues and blame the engine.
 
The question should be, how many sports cars putting out 250-400bhp make it as far as 60000miles?

[StavFC]

Can we not have a debate, not till I fix this bloody thing anyhow.
The comment was in jest, the engine is just some mass produced lump, and neither are worth either the toys our the pram reply or this debate.
 
Comparing a rotary to a piston engine of the same size is totally pointless mind, as it shares absolutely no attributes, good or bad, to one.

[Jit]

Did someone call?! Sounds like chipped apex seals from the symptoms you described. I done one a few weeks back that had chipped apex seals on both rotors. started ok but was crap down low with fluctuating idle vacuum and the engine was visibly shaking.

[BenLewisMav]

Interesting Stav. As above, both rotors having chipped seals is possible... A video of it starting/running might help? As I said with mine it would start on the key and run fine, seemingly slipping out from being better (almost \'normal\' at some points) to very rough idle + revving..
I guess there\'s no way you could pull error codes off the fcon pro ecu? Actually just thinking it is a piggy back isn\'t it, so the stock ecu is in the car and you could still pull codes off of it.. Worth a try esp if its intermittent.

[StavFC]

Jit- The engine certainly had a lot more movement than it usually does, but an engine thats missfiring etc generally does, so I didnt take too much attention.
Good point about the idle vacum- I totally forgot to check.
It does still sound mechanical then, damnit. Shame you\'re 90 miles away if you have a comp tester!
 
Ben- Good point about the video, I reckon thats a good idea, it does sound like your one did, and also how Jit describes too. Always thought about doing a walk around vid of the car, but never thought itd be when its fooked, lol. I\'ll do it tomorrow if all goes well, showing the gauges etc too. Cant do any harm at least!
And yeah, FCon is a piggyback as it uses the stock thing to run the OMP I understand. Its intermittant but never totally right, if you know what I mean.