So I've been having issues getting my 13b up and running on ms2. I'm running the latest 3.4.2 firmware.

The symptom was the car didn't want to rev past ~4500RPM. At first I thought it was fueling because the AFR would richen up. After pulling fuel in that area, the problem didn't seem to go away. To investigate the issue, I decided to make a 36-1 wheel simulator with an Arduino and try simulating on a test bench. To my surprise, there seems to be an issue with the leading ignition signal generated by the ECU. Here are some GTK Wave captures of the problem at different RPM ranges.



I've flashed ms2e version 3.4.1, 3.4.0, and 3.3.3 and I'm seeing the same behavior on all of them. I've attached my .msq file, if you want to give that a look.

Is anyone else seeing this?!?!

Things I've tried to narrow the issue down:

• I've disabled staged injection... doesn't make a difference.
• I've messed with the trailing split... doesn't make a difference.
• I can swing ignition advance around and I doesn't make a difference.
• I can reposition the #1 tooth angle and it doesn't make a difference.

The only thing that seems to affect it, is if I increase decrease the nominal dwell. With increased decreased dwell, the misfire occurs later in the rev range. This make me think it's related to the dwell calculation in the code, but briefly looking at the source code I don't see anything that stands out.

 

U need to post this on the ms extra site forum...that guy that is one of the developers and forum moderator here hasn't logged on here in over 2 yrs..not even sure why he is still showing as a mod. here

 

Thanks, I'll try reposting it on the ms extra forums.

After further testing, I found that if I drop my nominal dwell to 1.5ms the issue doesn't present itself within the operating rev range of the engine. I've yet to test it out on the car though.

I'll be sure to post here if the ms extra forums lead to any results.

 

Please post the msextra thread here to follow.

I am wondering if this is only an MS2 problem

 

This was in fact a bug in the ms2 extra firmware!

For further updates, follow the thread on the ms2 extra forum here.

 

Good job!, crazy that no-one ever noticed this issue before. I've had the same firmware on my rx-7 but used it in rx-8 mode with 4 coils so no issues.

 

Wonder how long this bug was in the code if using leading wasted spark? The above is an interesting post (post#3) from this thread
https://www.rx7club.com/megasquirt-f...s3pro-1131166/
There is no mention of the configuration settings but wondering if this would b a possible culprit?

 

Has there been a new release candidate to rectify this yet?

Edit: I see now that the 3.4.2 beta 5 version has the fixed code in it, so that means 3.4.3 RC6 will be the upcoming rc, but it's now out as of yet.

 

I've been on 3.4.3 beta 3 since I finished the car and was never able to get rid of the high rpm misfire. I took it to a dyno day and it seems like there's a consistent, repeatable misfire a little past 5000 rpm or 90 mph. This is happening after peak torque and my plugs are gapped to .022" so I'm ruling out spark blow out.

I recently updated to 3.4.3 beta 6 with the hope that the ignition bug was my issue but there's still high rpm misfire, feels pretty much the same as beta 3. I'm already running an FC leading coil but I've given up and ordered some ign1a coils since that's all I can really think of now. Some what disappointed that I could make 303 lb-ft of torque but only 309 hp but I believe if there was no misfire, it should've gone up to 330-340 hp?

 

change to C.O.P and you would not have the problem.