I've recently handed over IGN and FUEL back to the stock ecu and after doing so, the cars idles really poorly as if it's running on two cylinders. When warm it's fine and after a few cold starts (it's about 2degC here!) it's all fine now. It's almost as if the stock ECU needs to learn again how to run in sequential IGN?

I was running batch IGN with my MS1 using a cam-sensor, stock ECU is sequnetial.

It's not just a one off either. I did this a few months back and the same thing happened for about a day and then the engine runs flawlessly after that in all conditions.

Has anyone any ideas why this occurs?

http://www.ingenieure-reichel.de/upl...g_nb1.6_ms.pdf is the scematic I used when MS1 was controlling things.

 

Which two cylinders is it running on?

 

Impossible to say really as it only occurs for a few minutes during warm-up on the stock ECU. If I shut off and restart the engine again, it starts and runs fine. It's just the first start on the stock ECU after changing from MS1 that it occurs.

 

Not at all impossible to say. Start it, run to the engine bay, and start pulling plugs. I'm guessing they'll be no idle change on either 2&3 or 1&4. Which ever set doesn't change idle will kill the engine.

 

Stock injectors?

 

Yeah stock injectors.
I'll be able to recreate the issue if I give the MS1 Fuel and IGN again and then hand back to the stock ECU.

Fair point on pulling the plugs, but it was a pain in the **** to keep the engine from stalling so it'd be impossible for me to keep it running long enough to investigate the issue.