MS2 reset issue

[323driver]

I finally had time to install the MS2 in the car with a separate harness I built. However, at 2100 rpm, the ECU resets. Every single time I reach that rpm level, it resets but catches back at a slightly lower rpm. If I force it enough, it will pass over that 2100 rpm level and it runs fine from 2500 to 5500. I didn't bother going further. So basically, as soon as I reach that rpm range from 2100 to 2400 rpm, the ecu resets.

I'm running MS2 extra with no idle control, fuel and spark with the 4/1 cas setting and a single coil (I went back to 1 coil as the car wasn't starting with coil pack but I will go to coilpacks later), stock 220 cc injectors and no EGO feedback.

I did the input mods listed on the MS2 extra 4/1 cas webpage (reversed the disty signal input and added a 2nd pickup circuit connected to JS10) and did the miata output mod for ignition, driving the coil at D14 ith a 1K resistor and using the stock igniter and coil.

The car runs too rich (from the plugs) but until I can figure out the reset problem, it doesn't really matter as it's undriveable.

Anyone have any ideas why the ecu completely resets at a specific rpm range (2100-2400 roughly)? I looked at the schematics but have no idea what could case the reset. It works great at all other rpm levels.

Any help would be appreciated. I will post my MSQ and a datalog tonight.
Thanks

[therieldeal]

take a look at the voltages on your log, and the rpm signal. you could be picking up some sort of interference or maybe have a weird grounding issue?

i have a weird stumble around 2100-2200rpm, always have... never really worried about it i just avoid cruising at that rpm. i wonder if its the same thing haha

[Lex]

Log what is going on. Are you sure it's resetting or is it something else?

[323driver]

Log file

Here is the log file of the last run from yesterday.

It is indeed in between 2100 and 2200 rpm but it's not just a stumble, it's a complete reset that makes the car jerk.

What do bit7 and bit8 refer to? I noticed their status change during the resets.

1coil_oct4_4_2.zip

Somebody must have seen this before. I can even pay or donate money if somebody can figure this out, I just don't have the time anymore for this and need it running.

[Lex]

Here is the log file of the last run from yesterday.

It is indeed in between 2100 and 2200 rpm but it's not just a stumble, it's a complete reset that makes the car jerk.

What do bit7 and bit8 refer to? I noticed their status change during the resets.

[ATTACH]33581[/ATTACH]

Somebody must have seen this before. I can even pay or donate money if somebody can figure this out, I just don't have the time anymore for this and need it running.

You've got noise on your tach line, the whole unit is NOT resetting. I've dealt with something similar and you can have luck with different options. Read these forums if you want to tackle the job yourself: msefi.com, msextra.com. Many people have suffered from the same problem.

If you want me to fix and test it, then you'll need to send it my way.

[photoeye0]

Read this

http://www.wihandyman.com/forum/showpost.php?p=451387&postcount=242

[323driver]

Thanks Alex for pointing out the culprit and actually, you're right, it's not resetting as all the other values are still there. All the lights blink though, just like at power up, hence the reason I thought it was resetting.

I did the transistor mod today but for some reason, MS wouldn't see the trigger at all so I went back to the initial circuit.

Photoeye, Unfortunately, the above link applies for the 2nd tach trigger which I'm not using as I run only 1 coil, might need it later though. The primary input already has a cap before the processor port.

I don't have a scope so I can't really tell what is going on there. I guess the next step is to change the ed capacitors value, maybe that will help.

[323driver]

I figured it out. I thought I wasn't using the home trigger but I was, as my setting was 4/1 CAS. So I kept the optoisolator circuit but increased the cap value and used a shielded cable and it all fixed my problems.

Yesterday, I rewired the harness as I finally added the VB921 to the board to get rid of the external igniter and rearanged the signal grounds because I had some bouncy temp and tps readings, hope it still works, lol.

Thanks to all who helped, much appreciated.