Injector Sequencing

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Maddog6961
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Injector Sequencing

Post by Maddog6961 »

I just saw this feature and wasn't sure when it was added under the advanced menu. Does this feature allow you to sequence two banks of injectors? How does it work? I would love to be able to use a cam sensor to time each bank of injectors.
George Carstens
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muythaibxr
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Post by muythaibxr »

It allows you to select which trigger the first channel will start squirting on, then from there maintain that configuration across every burn. (Some people were reporting that after a burn, their engines run odd, and we found that it was b/c the injectors were changing what trigger they were squirting on).

So it can be considered "Semi-sequential" since it'll always do the same thing every time. It doesn't let you set exact injector timing.

Ken
Maddog6961
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Post by Maddog6961 »

COOL!

So lets say I had a 60-2 wheel on the crank and a single pin wheel on my cam sensor and I had everything setup properly in megatune for a coil on plug setup. How would I tell this feature to fire injector bank 1 when the cam sensor is triggered?

What are the other possible trigger options?
George Carstens
1984 BMW 533i turbo
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Maddog6961
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Post by Maddog6961 »

One point to note that I don't believe would be difficult to implement is that motronic 1.3 cars use a sparkwire inductance sensor on cylinder number 6 for injector bank timing.

This could be a simple solution for a lot of people if a cam wheel is required to make this work for people that don't have cam wheels. Would just have to take into account ignition advance?
George Carstens
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Serj
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Post by Serj »

Guys, is it possible to make 1 squirt for a bank not 2 banks for 4 cyl engine per cycle ?
md95
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Post by md95 »

Since i only have experience with semi-seq on 4 cylinder engines so far, I can only comment on that. To really take advantage of semi-seq, you really need to use a crank wheel, AND a cam wheel, to give at least 4 triggers per 720 crank degrees(1 on the crank per 360, and 1 on cam per 360, for a total of 4 triggers per 720 full cycle). If you only use a crank wheel and 4 cylinder wasted spark, then you only have 2 triggers. You can select "1" or "2", but all this does is put injection at the same point in time, but on the other pair of cylinders, it just inverts the time phase on the opposite pair of cylinders. When you use a second trigger from the cam, you can now select, 1-4 to squirt on, which gives more options for what point in the engine cycle to squirt on.

Semi-seq will only really be helpful(in my experience), when running large injectors and 2 squirt alternating. For me, idle quality went from slightly rough to perfectly smooth. For a 4 cylinder, you will have 2 cylinders getting fuel "at the right time" BTDC, while the other 2 cylinders will be 180 degrees earilier. That's as good as it gets until we get full sequencial injection timing.

I found the slightly rough idle to be because fuel was either getting injected too early, or too late on the intake stroke for a pair of cylinders(at idle, low rpm most noticable since air velocity is so low). It really depends on exactly where your triggers are in relation to engine cycle to get full benefit from it. It just so happened on my 4g63 with the 4/2 CAS that i can squirt on one pair of cylinders at around 77 degrees BTDC, and the other pair 180 earlier at 257 degrees BTDC. Easiest way to find the best trigger is to just try numbers 1-4 at idle, and listen carefully to idle quality. If you know where your triggers are in relation to engine cycle, this can help as well(this is how i figured out my settings on the 4/2 CAS).
-Matt-
1998 Mitsubishi Eclipse RS 420A Turbo- MS2 Extra- 2.1.0 Release
1992 Plymouth Laser RS 4g63 AWD Turbo MS2 Extra- 3.0.3s
Maddog6961
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Post by Maddog6961 »

So here is what I want to do.

BMW 6 cylinder engine - 2 squirts alternating

I would set the trigger on the cam so that the trigger event occurs at what I am going to call 0 degrees. 0 degrees will be when the intake valve is open on cylinder 5. Becuase I have two squirts alternating, injector bank 1 is going to fire at this trigger (fueling cylinder 1-3 with closed intake valves), and then 360 degrees of crank rotation later, injector bank 2 is going to fire (fueling cylinders 4-6) with closed intake valves. Am I correct in saying this?

For this to work, I would set the sequencing settings to enable and set injector sequence start to either 2 or 4, depending on when I want injector bank 1 to fire? Is trigger 1 always the crank trigger, even if the cam trigger passes the sensor first on startup?
George Carstens
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hassmaschine
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Post by hassmaschine »

Maddog6961 wrote:So here is what I want to do.

BMW 6 cylinder engine - 2 squirts alternating

I would set the trigger on the cam so that the trigger event occurs at what I am going to call 0 degrees. 0 degrees will be when the intake valve is open on cylinder 5. Becuase I have two squirts alternating, injector bank 1 is going to fire at this trigger (fueling cylinder 1-3 with closed intake valves), and then 360 degrees of crank rotation later, injector bank 2 is going to fire (fueling cylinders 4-6) with closed intake valves. Am I correct in saying this?

For this to work, I would set the sequencing settings to enable and set injector sequence start to either 2 or 4, depending on when I want injector bank 1 to fire? Is trigger 1 always the crank trigger, even if the cam trigger passes the sensor first on startup?
it makes sense to me - good idea using cylinder #5 intake valve to locate your trigger point.
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