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Warm up enrichment VS Lambda Target over ECT

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Hello Guys,

I would appreciate your opinions on the title comparison.

In my understanding, the 2 methods are essentially the same, as long as they are not being added on top of each other, correct?

Data logging on my Micra on OEM ECU, before switching to a Haltech Elite, showed that the car was running particularly rich (~0.80 λ) during driving while cold.

After switching to the Elite ECU, with a reasonable warm up enrichment, giving a λ of ~0.90-0.95, the car is very hesitant to drive, until the coolant is over ~50oC. So i am looking into adjusting the warm up enrichment to help it out.

Now, my question is whether i should keep working on the traditional warm up map, or allow for STFT earlier and switch to the λ target over coolant temp map instead.

All hints are welcome!

I'd suggest working on the coolant compensation tables to get it running perfectly, and not rely so much on the o2 sensor. In case the sensor is giving false readings or broken, you can still drive the car with no issues.

That's a good approach.

If the O2 sensor fails, the Warm up can still be done based on ECT and the rest on open loop.

There's two different things happening here. First of all when the engine is cold you will need additional fuel injection to achieve your target lambda and this is handled with the warmup enrichment tables. Beyond this though you will often achieve better idle quality and improved driveability when the engine is cold if you target a slightly richer lambda too.

The aim would be to tune the warm up enrichment until you're achieving target lambda with minimal STFT. You can then make target lambda changes and the ECU should track these when the engine is cold.

Hi Andre,

Thanks for the input. This improved driveabillity is exactly what I am after.

My main concern is that this engine runs anything but happy, unless reasonably reach (0.88-0.95) when the coolant temp is below~ 60oC, especially around idle. I confirmed that by logging on the OEM ECU. Being 25 years old, probably has the emissions tolerance for doing so.

With the lambda target set at 1.00, for running at normal temperatures, I am forced to warm up in open loop. With this in mind, i thought of using the Warm up lambda target table, to be able to also run close loop already at a colder engine.

I don't like running it so rich, unless I am forced to, to avoid hunting, and I believe it's better to rely on lambda target and closed loop for optimizing, once the Warm enrichment maps are reasonable.