Can anyone please explain where the oscillation in idle rpm -as seen in attachment - is coming from? The EGO-correction is not yet active.
MS1, Ford Pinto 2.0 OHC injected.
tia

Once my map was pretty close I turned off EGO enrichment for this reason.

I think there may be an anti-stall feature that enriches if the idle drops, maybe this?

More lightly that or you are pushing in to much fuel, that's what carbs do if you leave the choke out when not required. Back down the warmup enrichments.

Regards Mark

It would be easier to take a look at the actual log file to see what it going on, but it looks as if you are getting into a feedback loop caused by the spark map.

As the load increases, the spark advance increases, which reduces the load, which reduces the spark advance, which increases the load... and so on ad infinitum.

I would start by reducing the 1000 RPM cells between 25 kPa and 65 kPa to 10 deg and see if it helps.

With regards to EGO correction, it is possible to have EGO correction only active above a certain RPM set point.

The temperature is 78.9 deg C so you are already off warmup. No need to touch those settings. The MAT is 48.3 deg C. That seems to be quite hot. My MAT is usually around 25 to 30 degrees.

The AFR is 16:1. That is a bit too lean which won't help idle stability. Depending on the exact engine, anywhere between 13 and 14.7:1 would be better for a stable idle.

It'd be better if you posted your datalog and Msq file then we could see it in real time. As an aside if that's it at idle then your wasting a lot of your ve table entries are you not. Everything in the rows below in fact. Unless I'm mistaken???

You need lower MAP bins to tune for over-run, but it's a fair point. 1 or 2 over-run bins should be enough. Ideally you want the load and RPM bins to be clustered around the areas of high VE curvature.

Do you have any form of idle control?

here is the msq

and here is the logfile

again the msqfile

With such a high idle pulsewidth, I would consider moving the injector staging to 4 alternating or 4 simultaneous. It is recommended to have as many squirts as possible while keeping the idle pulsewidth greater than 2.0ms.

Are you sure the MSQ is for the log file? The spark advance in the log file doesn't seem to match the advance table in the MSQ.

There seems to be several problems in the log file:

Your throttle sensor doesn't seem to be properly calibrated. Fully closed throttle shows as 14% in the log file.

The MAT is way high. The temperature reaches almost 55 deg. Have you got the sensors correctly calibrated?

Lastly, the datalog looks like you just left the car idling on your drive. It would be better if you could take it out on the road and take a proper datalog. The datalog says that the engine is running about 10-15% too lean but that could be caused by a number of different things:

Wrong VE table
Wrong MAT sensor calibration
Wrong coolant corrected air-density curve

In the mean time I discovered a small air leak near the intake. I'll solve that first.
When the under hood temp is high, I still get backfires in the exhaust when not pushing the throttle. I think the MAT is right because the air intake filter is too close to the exhaust, hence the high under hood temp when not driving fast enough. How should a proper air-density curve look like?
I add the proper log and msq file of a warm up on the driveway followed by a tour on the road. tia for the analysis of these files!