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By Andrea Beraldo
#49190
Hi guys!!!
I have a problem with my e36 4 cylinder M43B18 engine.
I took an original 88 pin connector to keep my car's electrical system intact.
The problem is that in the manual the injectors are connected together like this 1-3 and 2-4.
The firing order is 1,3,4,2.
From what I understand if on the studio tuner I set the "paired" method with the stock wiring I will have the injection sequence 1-2,3-4.

INJ OUT 1 -> INJ 1-3
INJ OUT 2 -> INJ 2-4

It doesn't seem to me the most appropriate sequence.
If there was a way to change the activation order of the injectors from Arduino I would have solved the problem for example:
1-1-2-2

instead of:

1-2-1-2.

I'm not a computer scientist so I don't know where to go to change the firmware.

I hope I have explained the concept clearly.
Thank you.
By Andrea Beraldo
#49195
Yes I read the wiki but my problem is that I should change the activation order of the injectors from speeduino, instead of 1 and 2 and then again 1 and 2, I would need 1 then 1 then 2 and 2 having the injectors 1 , 3 and 2,4 connected together, not like in the photo which are 1,4 and 2,3.
User avatar
By jonbill
#49198
There isn't an option to change the order in which the injection channels fire. You have to wire your injectors accordingly.
from the wiki: "The injector channels always fire in numerical order (ie 1, 2, 3, 4) so your injectors should be wired to take your firing order into account."

Have you got a diagram of the BMW wiring/ECU pinout?
By Andrea Beraldo
#49200
jonbill wrote:
Sun Mar 21, 2021 5:51 pm
There isn't an option to change the order in which the injection channels fire. You have to wire your injectors accordingly.
from the wiki: "The injector channels always fire in numerical order (ie 1, 2, 3, 4) so your injectors should be wired to take your firing order into account."

Have you got a diagram of the BMW wiring/ECU pinout?
here it is the rectangle at the bottom is the ECU
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By theonewithin
#49216
It doesn't matter. Don't worry about it.

You are running batch fire so it really makes no difference.

Once over 25% duty cycle the injectors will be firing in the back of a closed valve anyway.

Don't overthink things.
By Andrea Beraldo
#49260
theonewithin wrote:
Mon Mar 22, 2021 12:37 am
It doesn't matter. Don't worry about it.

You are running batch fire so it really makes no difference.

Once over 25% duty cycle the injectors will be firing in the back of a closed valve anyway.

Don't overthink things.
Yes, but here we are not talking about batch injection in which all the injectors spray at the same time, when you couple the injectors you get semi-sequential injection,
In semi-sequential joining the wrong injectors some cylinders never fill while the injector sprays.
I asked here on the forum not only for my car, but also to get a clearer idea of ​​these fuel injection modes that often generate conflicting opinions.
User avatar
By PSIG
#49262
Any more than one injector is considered "batch" injection, even if there are multiple batches, e.g., a V8 with paired injectors would use batch injection across 4 sequentially-fired INJ channels (1,2,3,4). The injectors would be paired similar to wasted-spark ignition, where the pairs inject on the TDC of each cylinder. A paired batch 4-cylinder 1-3-4-2 firing-order engine with cycle sensor could be:
INJ1 - cyls 1 & 4
INJ2 - cyls 3 & 2

If set to 1-squirt simultaneous, all 4 would inject simultaneously. Millions of older engines use this quite well.
If set to 1 or 2-squirt alternating, each pair would fire 360° apart. Millions more use this.
If set to 4-squirt alternating, each pair fires at its two TDCs (2 per-cylinder). Even though only 2-channel batch, this is "double-shot" sequential, as used in many of today's systems.

If no cycle sensor, then 4-squirts simultaneous per-cycle can do the same even-fueling job, but the small pulse width may become a control concern for some injectors. Calculations or a quick test will tell you if this is an option for you, but as-mentioned most engines will run surprisingly well with any of the above combinations, so don't worry too much about it. ;)
By Andrea Beraldo
#49286
PSIG wrote:
Tue Mar 23, 2021 11:01 pm
Any more than one injector is considered "batch" injection, even if there are multiple batches, e.g., a V8 with paired injectors would use batch injection across 4 sequentially-fired INJ channels (1,2,3,4). The injectors would be paired similar to wasted-spark ignition, where the pairs inject on the TDC of each cylinder. A paired batch 4-cylinder 1-3-4-2 firing-order engine with cycle sensor could be:
INJ1 - cyls 1 & 4
INJ2 - cyls 3 & 2

If set to 1-squirt simultaneous, all 4 would inject simultaneously. Millions of older engines use this quite well.
If set to 1 or 2-squirt alternating, each pair would fire 360° apart. Millions more use this.
If set to 4-squirt alternating, each pair fires at its two TDCs (2 per-cylinder). Even though only 2-channel batch, this is "double-shot" sequential, as used in many of today's systems.

If no cycle sensor, then 4-squirts simultaneous per-cycle can do the same even-fueling job, but the small pulse width may become a control concern for some injectors. Calculations or a quick test will tell you if this is an option for you, but as-mentioned most engines will run surprisingly well with any of the above combinations, so don't worry too much about it. ;)
Ok yes that's right !!! If the injectors fire at the TDC there is no problem because in any case the fuel will always be stopped above a closed valve waiting to be sucked in.
The filling will be homogeneous for all cylinders as regards the ratio between condensed and non-condensed petrol.
The gasoline deposited will also lower the temperature of the cylinder head, correct me if I'm wrong.

The injection timing was my other doubt that did not give me peace because I was convinced that it was necessary to inject part of the fuel on the cylinders in the intake phase.

But what about sequential mode with one injector per cylinder?
In that case we use an injection timing right?

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