Application: 2002 Miata 1.8 VVT with MP62 supercharger. Fast Forward kit which ran well with minor issues. (hard cold start) Occasionally hard hot start. I took to a speed shop which convinced me changing to a MS3 would resolve all issues. This is when the real problems began. Now the car will start cold fine, drives strong and once stopped will not start for 10 - 30 minutes. Happens every time now. Also, if setting in line like idling for more than a few minutes the engine cuts out. Have to push off to side and wait for 10 -30 minutes. Shop will not respond to my calls or emails. What Have I tried? New CPS, New 80 Amp main relay, (if I recall this car has a new crank position sensor). Engine is total rebuild with <1000 miles since rebuild. Tried driving to fail start and pulled plug. Put new plug in lead and grounded (NO SPARK). MY LIMITATIONS: I am not good at anything electrical. I can look at fuses, I can check voltage and resistance but that's about it. All plugs look good, not fouled. Coils are not cracked and secondary test show correct resistance.

Where else should I look for a no spark condition after running for awhile? AF wide band also has failed several times now. But that is secondary to the start issue. Any thoughts?

 

Part of the reason no one replied to this thread is because you put it in the front desk section which is typically used for site issues. The reason I didn't reply when I first saw it is because you gave very little information. One of the huge advantages to a megasquirt ecu is the ability to see what the ecu is seeing for diagnostics and tuning.

Start by posting your current tune and a datalog of the issue.

 

Thanks for the reply, I have not posted often. Obviously I didn't post in the right place. My initial post was quite detailed and don't know if you saw this. My tuner always places me 2 months out before looking at the vehicle. Not knowing MS3 at entirely I'm at their mercy. Most recent update is that I've replaced the CAS, the coils, the main relay with an upgraded Denso 80 Amp, Fuel pressure is normal at key on and running and hot start conditions. Since replacing the coils the car started every time until today. 84 degrees outside and drove it to 3 stops before hot start failure once again. Waited 20 minutes and fired up again. The other issue is while at a light, or in line the car idles fine, then starts an occasional bump (miss) then dies. If I keep it in neutral and idling at about 1200 to 1400 it will not die.

 

I did see it and I disagree. A detailed post would have included a datalog of the issue and the current tune file. Those will tell us far more than you could ever put in to words.

 

Ok, I'm going to have to get this information from the Tuner.

 

Just to clarify (because "CKP", "CMP", "CPS", and "CAS" often get mixed up), are you saying that you have changed the cam position sensor yourself, and you believe the crank angle sensor is new as well? Or was that just referring to the differences between the earlier versus later model crank angle/position sensors? Anyway, just wanted to clarify exactly what was changed without using acronyms (or at least assuming their meaning).

 

The Cam Position Sensor, the crank angle sensor, the main relay and the coils have all been changed by myself.