Diesel using WMI?

[Dust Buster]

Wikipedia suggests you have a Toyota 1N-T 4cyl 1453cc engine

Thanks, but it's a Renault / Dacia K9K 898 motor, which is also used in Nissan, Merc and Volvo.

Luckily, it has Nikasil coated cylinder walls and piston rings and uses semi-synthetic oil.

[BLSTIC]

In a gasoline engine water flow is supposed to be in proportion to fuel flow. Usually 25% or so is when the magic truly starts.

Although that's probably too much for a diesel, you'd probably be served by using a load input for your system that scales as least partially with fuel. Boost is not a good indicator of load on a diesel

Say tps, or a potentiometer wired between tps and airflow will give you a blend of both of those outputs for a good approximation of fuel demand.

[Dust Buster]

In a gasoline engine water flow is supposed to be in proportion to fuel flow. Usually 25% or so is when the magic truly starts.

Although that's probably too much for a diesel, you'd probably be served by using a load input for your system that scales as least partially with fuel. Boost is not a good indicator of load on a diesel

Say tps, or a potentiometer wired between tps and airflow will give you a blend of both of those outputs for a good approximation of fuel demand.

Yes, I've seen those figures, but I'm already at 127% with this nozzle.

I looked carefully at my scan tool logs when choosing which source to monitor.

Sources available for this controller:
1 MAF / MAP (0V to 5V)
2 Injector duty cycle (0% to 100%) based on single pulse injection (not suitable in modern diesels)
3 Frequency MAF (40 Hz to 220 Hz)
4 Frequency MAF (400 Hz to 2200 Hz)
5 Frequency MAF (2k Hz to 14k Hz)
6 Progressive Pressure Switch based on boost (or vacuum)
7 EGT (in conjunction with boost)

Why did I choose Progressive Pressure Switch based on boost?

There are a lot of hills in my travels around Cape Town and even mountain passes nearby. I use engine braking a lot (in gear, “ignition” on, but no accelerator being applied). The injection cycle goes to zero instead of the normal “up to” nine injections per compression stroke. Injection cycle would have been my first choice as it also increases in duration under load. However, the current technology of the injector duty cycle signal converter in today's controllers can only handle a single signal per compression stroke. When I looked at the MAF readings when engine braking, the signals didn't drop as quickly or deeply as the boost pressure as air was still being pulled into the engine based upon rpm. Thus, I choose the more analogue Progressive Pressure Switch to not flood the combustion chamber with mix when engine braking.

[BLSTIC]

Well that 125% could be part of the problem. That's a lot. 5% of that as fuel is a significant amount of extra fuel in the chamber, especially considering that fuel is all there ready to go boom when the diesel gets injected (which is a huge fire starter compared to a normal spark plug).

Now as for your load problem.

Do you have a voltage outputting airflow meter (and/or can you install one) and can you get a voltage tps somewhere like the throttle pedal? Are you able to log a potentiometer (voltage divider) output that's wired between the two?
If you did, you'd have a signal that would be low-ish (2.5-3v probably) at low rpm full throttle and climbed to 5v with increasing rpm/boost. It would also drop to 2.5 at maximum airflow as soon as you take your foot off the throttle.

[Dust Buster]

Well that 125% could be part of the problem. That's a lot. 5% of that as fuel is a significant amount of extra fuel in the chamber, especially considering that fuel is all there ready to go boom when the diesel gets injected (which is a huge fire starter compared to a normal spark plug).

Now as for your load problem.

Do you have a voltage outputting airflow meter (and/or can you install one) and can you get a voltage tps somewhere like the throttle pedal? Are you able to log a potentiometer (voltage divider) output that's wired between the two?
If you did, you'd have a signal that would be low-ish (2.5-3v probably) at low rpm full throttle and climbed to 5v with increasing rpm/boost. It would also drop to 2.5 at maximum airflow as soon as you take your foot off the throttle.

Thanks for the independent verification – I think the incorrect nozzle size has been my main problem. I'm using the smaller of the two nozzle sizes recommended by the OEM.

I can order their smallest nozzle which flows a third as much, which will hopefully allow me to increase to 15% alcohol.

I have a mass airflow (MAF) meter, 0-5V, which the ECU monitors and I can see via my scan tool. Diesels don't have a throttle plate, but it uses the accelerator cable sensor, which I can't see, for fly-by-wire adjusting the injection duty cycle (along with load, etc.). The MAF isn't as responsive as the psi to load. The MAF is directly correlated to the rpm.

[BLSTIC]

most pedal sensors have two 0-5v outputs in their wiring. One goes 0-5v from 0-100% and the other goes 5v-0 from 0-100%. You can usually get these at the pedal or the ecu.

Unless you are saying you have a cable throttle that goes somewhere with no wiring? I've seen semi-electronic non-common-rail pumps before and they do some weird things and I don't know how to deal with them.