Hi All,
my 65000km 2010 R3 has just suddenly developed a considerable power loss from 4500 up,
no codes
car has no Cat, near full tank of fuel
have BHR coils, and plugs done about 3000ks ago
Idea for cause are
SSV solenoid?
Fuel pump ?
coils?

is there a best way to differentially diagnose between these possibilities?

 

Sounds like your car may be in "limp mode"...perhaps d/t an OMP issue. M/b worthwhile to search it on the forum. Good luck.

 

If it was in limp mode it wouldn't go over 4k or 5k rpm.

The SSV and VDI solenoids can be tested. Remove them, put a MityVac hand pump on the port that connects to the vacuum accumulator (opposite side of the solenoid from the connector). Pull 10 psi vacuum and see if it holds. If it does, apply 12v across the pins and see if the vacuum is vented to atmo.

 

Check your MAF sensor?

 

cheer,
will do,
seem likel the easiest thing to do

 

True... somehow misread that...

 

Engine Power Loss

• chokes as revs increase
  • O2 sensor failure (too rich)
  • MAF failure
  • MAF disconnected
  • e-shaft sensor fouled
  • accessory belt fraying
• high end power loss (hard fuel cut)
  • Rev limit reached
• high end power loss (jerky and stumbling)
  • Ignition failure
  • fuel pressure loss
  • e-shaft sensor fouled
• high end power loss (smooth)
  • Catalytic converter clog
  • air filter clog
• low end power loss (smooth)
  • Engine compression loss
• low end power loss (stumbles)
  • Ignition failure
  • front O2 sensor failure
• revs slowly but smoothly
  • O2 sensor failure (too lean)
  • catalytic converter clog
  • air filter clog
• sudden power drop at a specific rpm
  • Intake valving actuation problem
• trouble getting to redline
  • Ignition failure
  • front O2 sensor failure
  • catalytic converter clog
  • air filter clog
  • e-shaft sensor fouled
  • fuel pressure loss
  • MAF failure

 

Still not had time to look at it,
but today it thew a pending P0302 code, on cold start,
started v badly,
but was fine once warmed

 

another bad start yesterday,
still same pending code,
ill change the leading rear coil on weekend,
hope that sorts it

 

Thought a little more about this.

I wonder if maybe a plug wire slipped loose or one plug was not seated correctly and that could be causing your code? I would check your ignition system first since that was the last thing you changed in the car.

 

I think its the rear leading coil, will change soon as time permits

 

for that ignition system the first thing you should do is check all the coils and wires per the S1 DIY thread. I recommend checking at the wire spark plug connection first; good spark test then both wire and coil good; weak or no spark then one or other is bad. Also make sure the main ground wire is secure and proper. Also check to make sure the coil harness wiring is not rubbing against the front engine lift hook; common problem.

https://www.rx8club.com/series-i-do-...-wires-222641/

More likely to be a leading rather than trailing issue for that significant of a loss. Also reset ESS profile, clean and test ESS sensor if problem persists.

also, get a vacuum gun and pull a vacuum on the solenoid tank and see of it holds. No need to pull solenoids if it does, only if it leaks down. Most likely an SSV issue if starting from 4500 rpm (should open after 4100 rpm under WOT, otherwise no secondary ports). Make sure the actuator arm opens and closes smoothly.

Any unusual exhaust smoke/smell on start-up? Running rough until warm could indicate a leaking coolant seal. Might cause a misfire code too.
.

 

Not sure what you meant by leading coil. Do you mean the coil that connects from the wire to Rotor 2 leading plug? I'd check it out before trying to drive it anymore.

 

No other signs of ,
just occasionally terrible rough starting after damp cold night,
and is fine after about 1 minute, still gutless through mid rage,
so,
maybe combination of issues
got some new coil on the way,
and don't know how long till I have time to do much more on it

cant rule out coolant use yet,
but am monitoring it,
don't know why mazda made the coolant tank so hard to read,....

 

In the end this was a combination of issues
1) stuck (shut) SSV that didn't throw a code,
2) weak Leading coil on rear rotor
3) plug wires were routed so that the longer leading ones were on the trailing,
so they were very tight,

I replaced coils,
had ssv " unstuck" and also replaced solenoids at same time,
so far so good.

 

Congratulations, but you need to be concerned about why the SSV is stuck. That’s generally going to indicate a possible problem elsewhere that’s resulting in those deposits.

 

Yes, know its not a done deal,
I wonder if a failing coil for 5000K's might have been a contributor,
and I had been a bit lax on really thrashing it out daily
it now feels like it had more power than it ever had,
so maybe it was partially stuck the whole time

Im just surprised it didnt throw a SSV code

 

Because Mazda only designed it to throw a code if it’s stuck open, that’s why.

 

I see,
I thought the code was for stuck shut,
do you think the dying coil could have been part of the problem?,

 

Well bugger me,
the misfire is back
a few days without it,and this morning,
rough start and same P302COde same code, rear rotor,
anyone think it might be the coil adapter harness as well?
SSV def working still,
so,
?
harness?
PLugs?
Pug wires?
Leaky injector?

 

well you have to check those coils again

 

Sorry to grave dig, but what was the final outcome, OP? I've had a very similar problem!