[rusEfi] Nissan engine KA24DE #36

[AndreyB]

injection = f (map, VE, target_afr) see http://rusefi.com/wiki/index.php?title=Manual:Software:Fuel_Control#Speed_Density

so map, ve not changed - same result

map or ve changed - result changes. Expected behaviour I guess?

[AndreyB]

"output overflow stat" is a minor warning, it does not affect your engine operation. I will now increase some console data buffer size but usually you can just ignore this

as for your idle, is your idle valve connected? do you have fly back diode installed? does your RPM go up or down if you change idle position in manual mode?

[filip5]

One question about IAT. Where is IAT supposed to be mounted? Does it measure the intake air temp after the throttle or is it measuring the ambient intake air temp before the throttle?

Thank you

[AndreyB]

On mazdas IAT is close to air filter - either on MAF on older designs or on the air filter body on newer ones -pretty far from throttle body. Do not remembe Neon IAT position for sure but I believe it was again before throttle body.

[stefanst]

In a perfect world you measure IAT inside the intake manifold, since that is the most accurate. Many applications will substitute any location after the air filter though.

[filip5]

My Nissan has this idle valve that has 4 wires . I think rusefi works with 2 wires.

Any idea which wire to connect?

Thanks

[filip5]

Hard start. I have this engine sometime start very easily and nice and sometime does not start at all. I am posting 3 rusefi engine sniffer images from these hard cranking. As one can see the ignition for the start of the first or all other coils is not consistent and near top dead center. Cranking RPM are about 260 to 330. The ignition advance is 3 degrees, but here you can see that it changes a lot. The same can be said for the injection phases as one can see in the pict. Any way to fix this?

[AndreyB]

My Nissan has this idle valve that has 4 wires . I think rusefi works with 2 wires.

Any idea which wire to connect?

rusEfi red board only handles solenoid-type idle valves. It looks like you have a stepper side which is not handled out of the box

See also http://rusefi.com/wiki/index.php?title=Hardware:Stepper_motor

[filip5]

Thanks. What type of idle valve do you recommend? Do they draw a lot of current? Can rusefi handle them directly or should I use a rely ?

[AndreyB]

I would not say that i am happy with my own cranking parameters. From my limited experience the amount of fuel makes a huge difference, let me speculate that cranking confusion could be caused by too little or too much fuel. Can you please post your current tune?

Too many variables unfortunatelly between diffrrent cars. I was recently suprised to see how differently two of my miatas with same engine but different fuel systems behave.

[filip5]

If you look at the second pict is shows that the ignition sometimes goes way before dead center and the engine backfires. Same with the injection timing. That is why the simultaneous fuel injection on cranking seem to work better.

If you could be able to control in a fixed way let say the injection to happen at 270 degrees before tdc and the ignition to have a fixed dwell of 5ms let say but always at 0 degrees the cranking will work fine. Can that be done?

thanks

[AndreyB]

Thanks. What type of idle valve do you recommend? Do they draw a lot of current? Can rusefi handle them directly or should I use a rely ?

relay would not work since these valves are not on/off, these ones have variable position. Any chance you can get a spare valve with a pirce of harness? this case I would be able to set everything on a bench.

[filip5]

Problem with "warm up fuel correction". See video:
[video]https://youtu.be/fjJseoEZPiY[/video]

[AndreyB]

Please post your currenttune and logs

[filip5]

Tune and logs attached.

[AndreyB]

I can open the tune but the log is very short, I believe it does not show the jump or much change in CLT at all. Can you please "start logging" and reproduce the problem one more time? I think there is also a setting in TS to control data rate, the higher the better for this.

I've noticed 70.97 followed by 70.97, not sure if that's a problem but values should not be equal.

[AndreyB]

https://github.com/rusefi/rusefi/issues/440

[filip5]

I get this "need burn" in the TS. What is the meaning of it? Does it require for more fuel injection? If it so why and on what basis if we are looking for AFR of 14.64?

[AndreyB]

"Need burn" means it needs to save data into the chip which it can only do while engine is not running.

[filip5]

Ok

[filip5]

Would it be possible to have a TS project of a properly working Rusefi car uploaded here so I can see the basic settings of idle valve, fuel table, fuel injection phase, fuel injection closed loop, warmup fuel man multiplier etc?

Just to have an idea where they should be set at.

[filip5]

I have my Nissan Altima running on Rusefi and I can take the car on the road and drive it for hours with no problem. But I have a problem with car chocking as soon as the gas pedal is pressed hard from stop position or park to go on drive or reverse.

If I press the pedal slowly or moderately quickly it will not choke, but as every one knows we press the pedal very quickly so I would like this problem fixed if possible. When it chokes I noticed the fuel pressure going higher in the actual pressure gauge by almost 1 bar and the AFR going very lean for a second even though the fuel injector shows an instant increase in the TS gauge as per table of the fuel injections as soon as MAF value is instantly increased. So I think there is a problem there with the actual fuel being injected during this brief time of sudden MAF value increase even though the TS shows that fuel was injected.

Attached is the entire project of TS and a link to the video I made:

[video]https://youtu.be/DlyQwUGrQno[/video]

[Abricos]

If you wanna fix that ...
i think you need DYNO stand to make tuning maps ...
And a professional who knows how to do it ...

[AndreyB]

The problem of "if I hit pedal quickly" is called acceleration enrichment - my understanding is that tuning in steady states is first step, and tuning for transition mode comes after that. We have acceleration enrichment somewhat covered on http://rusefi.com/wiki/index.php?title=Manual:Software:Fuel_Control#Acceleration_Enrichment

For a tune of a real car for instance there is http://rusefi.com/forum/viewtopic.php?f=3&t=906&start=150#p25906 - there you have logs and tune for the race car, and trust me that tune worked pretty well for real racing which trust me includes a lot of stepping in gas pedal.

Now that you mention that it soulds like I should make my "tps to tps" acceleration enrichment map the global default so that people can use it as starting point.

[filip5]

Thank you. I will test it and post here the results.

[filip5]

I tested the acceleration enrichment and does not seem to work. My engine is a 4 cylinders so I placed 12 cycles, 3 per cylinder and other values set to 2. The issue stays, the car chocked and the fuel pressure showed sudden increase again.

I think the issue is not that the fuel goes into the walls during the pressure increase as the throttle is suddenly pressed. The oxygen sensor is showing the engine going lean and one can
speculate that the fuel is going into the walls instead of the cylinder but the fact that the there is a sudden fuel pressure increase as the MAF is increased does explain that there is a shortage
of fuel for a moment which is not being injected and showing as pressure increase instead.

I have not connected the TPS potentiometer as I am working with MAF only and trying to solve one problem at a time.

Attached is the project and 2 data logs if one needed to see them. The first is short because the engine shut down quickly the second (a) is a bit longer.

[AndreyB]

I have not connected the TPS potentiometer as I am working with MAF only and trying to solve one problem at a time.

At the moment TPS-based acceleration enrichment is the most successful one, it has the most flexibility with the "from TPS to TPS" table. This is more flexibility comparing with engine load based enrichment which is set via a number of magic thresholds.

In your load-based enrichment your threshold is set to "2" which alongside your MAF-based engine load is 2 volts on MAF. On one of the logs we see how extra fuel is only activated once only for the largest spike in MAF voltage spike.

[filip5]

Hi there. So what I am supposed to do?

Any suggestions how the enrichment table should look like ? How can I fix this problem? From the graph it looks like the fuel injection is not keeping up with the MAF even. I have to also state that this spike of
fuel might no be real at all because why is there an instant on the fuel pressure increase?

[AndreyB]

First step wiring and calibrating tps

[filip5]

ok, I will wire it tomorrow.