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Rotary cold start tuning problem Link G4+

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Hi everyone

I am using premix for my rx7, and on every cold start or even water temp below 60C the car will blow blue smoke like crazy. But the exhaust soon clears afterwards.

The car starts right up without the need of pressing the gas pedal, however it will be nice if i dont choke the ones around me.

I tried to turn down the post start and warmup enrichment, but no visible difference.

Could please somone guide me a direction on which setting I should be fiddle with.

Thanks a million in advance

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I would target whatever AFR the car needs to run nicely at idle when its cold. Go as lean as possible. They kind of just naturally smoke, its just the way it is, especially when cold in the morning. Ive been told that the oil that was trapped in the chamber, slowly makes its way to the bottom during the night, and then is immediatedly burned at startup.

Here is a video of mine starting. yours about the same?

https://www.youtube.com/watch?v=kKpyO2g5lUY

Mine smokes alot worse at startup, but much shorter duration before the exhaust clears up.

AFR are fairly stable around 13-14 till fully warm

Should I be reducing the cranking enrichment until the motor begin cranking for longer? Will that help with the smoke?

Ive gone through the cold start webinar and the help page on G4+ but still dont quite get each setting's ultimate effect on the motor. Could someone please clearify it for me.

Thanks

I cant remember exactly without looking at the software, but i will generalize

On the link ecu, you have the following. Priming pulse, cranking pulse, after start enrichment, warm up enrichment.

Priming pulse activates once the ignition turns on and gives it a shot of fuel before the key is turned. This is to help make startup more immediate on troublesome engines

Cranking pulse is how much fuel is delivered DURING cranking. Again, to help the car start cold, etc.

After start enrichment is an enrichment applied that is time/temp based. This enrichmnent will be active until the time that you have set for it, decays. it will then move to the warm up enrichment table, which is coolant temp based. This table will keep applying an extra percentage of fuel (usually based on the fuel map) until the engine passes the temperature points, and gets to full warm, where you should have 0% correction.

Hope that helps?

Hey Thanks Evan, Ive got my cold start up perfect now, minimum smoke and immediate startup without accelerator.

I reduced Cranking, poststart and warmup enrichment for cold start, it was too much fuel before.

But, I cannot get the engine to start without feathering some gas when the coolant temp is above 70C. I reduced cranking enrich from 15 to 0, but still no good. Does that mean im still too rich to start? What should I adjust now?

When the engine is hot it catches but just keeps turning over, it will keep doing this until I press some gas.

I left my 'prime pulse' OFF for all temperatures.

Hi- my pick is you can reduce your fuel numbers at points lower than the idle speed . for example if the engine idles at 1000 rpm and you have rpm columns below this point ( say 750 and 500 ) reduce these numbers as when the engine is cranking they come into play . But i think it will effect the cranking enrichment numbers you have already set so they might need some adjusting . Not an expert by a long shot - but just an idea . That is of course if it is to rich at cranking .

^^what he said (=

Cheers guys, will give it a shot :)

Problem solved, removed fuel from main fuel table.

Thanks for the help guys!!!

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