Hi Folks,

I have a series one RX8 with an rew engine.

I am using the rew front cover, FD throttle body, adaptronic select ecu and the FFE trigger wheel kit with the FFE renesis wheel.

In July we had the car on the dyno for emissions tuning and found that at 6000 rpm the tacho stops working and shortly after the engine starts misfiring badly.

Here is a link to a video of the problem,


I contacted adaptronic and they cant figure out what is causing the problem.

I followed their instructions on setting up the timing (locking it and checking the timing and its correct) , using the correct trigger settings in the ecu etc and still the problem is there.

Mad Max sent me an ecu file with some settings but that didnt solve the problem either. (he said he had a similar problem and upgraded to a modular and it solved his problem)

I am at the point now where I need to tune the car (dyno tune for power etc) but have a severe misfire and cant find the problem.

I have spent hours searching for a fix online and cant find anything.

Apparently this is a common problem, I was hoping somebody has found a fix.

This is the only problem with the car and its driving me crazy.

Any help would be greatly appreciated as Im at a loss to sort this problem out.

Thanks.

 

Also forgot to mention, I am using ls2 coils, would anyone have the dwell in milliseconds for these colis please ?

 

I have used as little as 3.5 dwell on the coils with no issues at high boost and water being injected. At 4.0 and higher life of the coil seems to be much less. Those trigger wheels seem to be a problem. I use rx8 wheel and 0 problems

 

My dwell is currently set at 3.5 ms. It was set that way by Mark at adaptronic however he recently told me to put it to 4.5 ms, Ill try that tomorrow.

Are you using a renesis front cover so that you can use the stock rx8 trigger wheel ?

 

Yes I use the rx8 front cover.

 

Have you scoped the trigger signal when the problem happens?

Does the Adaptronic have a trigger scope built in? I've ever used one.... some of the newer ECU's have built in ones

 

 

@dannobre, Im not sure if the ecu has that feature but I did send Mark at adaptronic a log file and he said that everything looked fine. (which is really strange as there is definitely a miss, like as if its bouncing off the rev limiter)
He said that the problem is possibly in the stock ecu and even mentioned that Max had the same problem and upgraded to the modular ecu.
Ill have a look if there is a scope function.

@mad666max I will try and play with the dwell settings today and see if that helps the misfire, it sounds like its hitting the rev limiter but I raised it to 8000 rpm.
I just looked on the banzai website and couldnt find the bracket so I sent him an email to see if he still sells them.
I would prefer to use the stock rx8 trigger wheel.

Thanks for the replies, I will let you guys know how I go with the dwell settings.

 

Just an update guys.
Today I brought the cas closer to the trigger wheel (1mm now, before it was 1.6mm) and played with the dwell settings.

Before at about 6200 rpm the tacho would stop working and just after that it would misfire.

I first tried 4.5 ms (it was set a 3.5 ms) and took it for a drive, the tacho went all the way up to about 7500 rpm and then stopped working and would misfire.

I then tried 4.2 ms, the tacho went all the way to 8000 then would misfire a bit but I think that is because I have it tuned too rich (about 10.8 afr at -5hg, I kept the car in vacuum for safety)

Under boost the car has much more torque and power down low too.

I then tried 3 ms just as an experiment, the tacho went to about 7300 and it would misfire but again I think because its so rich,

I dont know if it was bringing the cas closer to the trigger wheel or the dwell settings but the problem has definitely improved.

Tomorrow I will try to bring the cas a little closer and see if that helps.

 

What plugs are you running and what gap?

 

That was actually the next thing Ill change, Im using ngk 7's on leading and 9's on trailing (for FD, cant change the gap) but for the dyno tune will be using 9's for both. I figured the 7's may cause some of the misfiring too.

My main concern is the tacho cutting out.

 

if the tach is cutting out you are likely losing the crank angle sensor...... that's not something you want to happen..... no signal no spark or fuel..... It is also unlikely to be a spark plug heat range issue.... crappy plugs maybe... but you won't have plug issues from short runs.

I think most of us are running 10 heat range plugs for higher boost and HP

 

@dannobre I will try bringing the cas even closer to the wheel and see if that helps.

I will also try to get a banzai bracket and run the rx8 stock trigger wheel too.

 

The spark plug comment was more of a gap issue than heat range. You could always try a gap-able plug down to 0.02" and see if your misfiring goes away. If it does then your ignition system may be too weak. I would see how the rx8 trigger wheel and rx8 CAS works. I suspect it might fix your issues.

 

Maybe you just misstated what you have, but “LS2” coils are not the same as the GM “D585” coils people are using on the RX8

 

@TeamRX8 I am using ls2 coils, not d585's or the yukons, just ls2 coils from a v8 car that is available here in Australia. (Holden Commodore)

Just an update guys.

I managed to solve the problem.

I was able to bring the CAS closer to the trigger wheel (0.3 to 0.4mm).

I had to extend the CAS wires when I did the swap but I didnt use shielded cable.

I went to the wreckers and scored a piece of the rx8 cas cable, I extended my one using that and now the engine revs cleanly to 8250 rpm.

Thanks for the help and suggestions guys,

Much Appreciated.