MH44 EFI tuning for today.

I got started on the tuning today.

I adjusted the opening time delay on the fuel injectors to what they should be.

I cranked the timing up to 30 degrees from 26 at full RPM, with 18 up from 12 degrees @ 600 RPM, that really seemed to light it up, I still have to decrease these values at full load to simulate vacuum advance. I would still appreciate if someone could get me the advance tables from a Farmall M or MH44, they should be close.

I had the AFR richened to 13.5 at idle to 12.5 at full load, I cranked that back to 14.5 at idle and 13.1 at full load. I have to run the tractor at each RPM and load range to let the autotune correct the fuel values. I was able to do some today, but found a sawtooth throttle can jump 2 -3 hundred RPM between teeth. I ended up slowly moving the throttle between the teeth, it was a real pain. I was not able to adjust the dyno on each range by myself. It would be super easy to tune one of these with electronic throttle and dyno control. I would run a program that set the RPM, then ran the Dyno up for each RPM range and let the autotune do its job.

The tractor puffs a little bit of black smoke when you advance the throttle quickly, I may back the throttle enrichment ramp down a little.

The tractor put out full HP after these changes a lot easier than it did last time, I think the timing was a little slow and the mixture too rich.

There is no blow by when at idle or partial load, but a pretty constant blow by when the engine is run at full HP for several minutes, there is only about a dozen hours on the rebuild.

I did not get the EGT hooked up today for measurements, that takes a different computer and I was just not that prepared.

MH specs on the 44 gas is TDC at low idle, and 16 degrees total crankshaft at 1350 full load speed. Lower compression kerosene had 23 degrees total. I've found several times on the dyno too much advance can sound good but power falls off under load, especially on lower speed engines.

Two of my favorite posters. Your knowledge impresses me. Keep on posting.
Jim

Did you "load" it or are you just getting it going???

I cranked down the dyno and loaded it up fully, was running about 45 HP

I really like reading your posts about the 44 EFI, and I am sure you know to get the max power on a gas engine under full load the AFR need to be 14.7 to 1

Yes, I am slowly leaning it back, do not want to burn a piston.

This is from Garrett turbo page

Leaner AFR results in higher temperatures as the mixture is combusted. Generally, normally-aspirated spark-ignition (SI) gasoline engines produce maximum power just slightly rich of stoichiometric. However, in practice it is kept between 12:1 and 13:1 in order to keep exhaust gas temperatures in check and to account for variances in fuel quality. This is a realistic full-load AFR on a normally-aspirated engine but can be dangerously lean with a highly-boosted engine.

If you run it that lean under full load you will melt pistons. Every computer controlled engine is richened at high load , just like the old carburetors in cars had "power valves" that opened at varying vacuum settings to add fuel under high load. A lean mixture will make more power , it just won't make it very long.

having the pyrometers is a good idea you can tell exactly how much is too much.