Moving from batch fire to fully sequential

[se7ensport]

I now have the car running at the lower end of the VE Table and could begin to populate it, however, I planned to run fully sequential if possible and don't want to waste time going further across the table if it's likely to change.

But from reading the wiki it would appear that I need a cam sensor for this which is a route I'm not going to go down due to time & effort.

I wanted to use sequential to reduce the pressure fluctuation in the fuel rail and to keep the injector cycle down. I thought it would run by multiplying the VE table figure below by 4, setting the Alternate banks from h[0] to 3 and injector outputs to 4,1,2,8 but this doesn't seem to work and don't understand why a cam sensor is required for this.

I'd happily settle for firing the injectors in pairs, but unsure how to set this or which to pair (i know it's be a binary mask but thats it), if i do this would my VE table values need to double?



http://www.box.net/shared/splbgd7rd3

http://www.box.net/shared/v6qnrjjfue

[rob@vems.co.uk]

you can fire injectors in sequence without a cam signal.
Just set your table (starting from 3 up to 0) 1 8 16 2
And now you'll need 4 times as much fuel from the ground up I'm afraid...

[se7ensport]

I assume I also need to change the Alternate banks from h[0] to 3?

[se7ensport]

you can fire injectors in sequence without a cam signal.
Just set your table (starting from 3 up to 0) 1 8 16 2
And now you'll need 4 times as much fuel from the ground up I'm afraid...

Just had a look at my previous settings that I took from the wiki and for sequential it shows for 1-3-4-2 firing (which is what I have)

"Remembering the binary pattern above, in Settings->Injector Outputs you will set:

    * 0 to 4
    * 1 to 1
    * 2 to 2
    * 3 to 8"

[rob@vems.co.uk]

Ignore my last post.  1, 4, 8, 2 or 4, 8, 2, 1
It depends on how the engine is setup regarding coils and injectors.

You need to match injector channels 1 & 8 with the coil channel for cylinders 1 & 4, and channels 4 & 2 with the coil channels for cylinders 2 & 3.

Rob

[Arjan]

you can fire injectors in sequence without a cam signal.
Just set your table (starting from 3 up to 0) 1 8 16 2

Hi, sorry to interrupt this thread, but do you mean that VEMS can be configured for sequential injection without the
use of a cam sensor?

[rob@vems.co.uk]

Yes you can fire each injector sequentially, the level of success does depend on the trigger type you have.  What engine is this on?

[Arjan]

thx for the reply..
In the near future I will probably buy VEMS( over megasquirt). I would like to use it for my escort rs turbo project ( cvh engine, 36-1 triggerwheel + vr-sensor )

[rob@vems.co.uk]

We had a nice result on an Escort RS Turbo when APT did one, it took a fair bit of messing around because the existing loom was old and the ground wires were a bit rubbish, but using a V3 loom made the whole thing work a load easier.  You're lucky in Holland as you have DP Engineering who did a lot of development work on VEMS (Dave there wrote a lot of the firmware), and they've just got a DynaPack dyno.

[Arjan]

We had a nice result on an Escort RS Turbo when APT did one, it took a fair bit of messing around because the existing loom was old and the ground wires were a bit rubbish, but using a V3 loom made the whole thing work a load easier.  You're lucky in Holland as you have DP Engineering who did a lot of development work on VEMS (Dave there wrote a lot of the firmware), and they've just got a DynaPack dyno.

Thats good to hear I intend to buy a new VEMS harness as like you say its a lot easier to work with. When the car is running on a roughly compiled basemap I will take the car to DP Engineering to get it fine tuned, Im looking forward to get it to install on my car, gonna be awesome to get the car running :p
Do I need a cam sensor in order to have a working sequential injection setup and would that be a Hall sensor or audi trigger ( 2 options to choose from in the webshop) ? thank you

[rob@vems.co.uk]

Stick with the crank sensor alone for the time being.  You set the injectors to fire sequentially but they will not be in phase with the engine, but this does not matter as long as you inject when the inlet valve is closed.  The inlet is closed when ever the coil is firing (as the cylinder will either be on its ignition or exhaust stroke) so in the case of a 1, 3, 4, 2 engine
Ignition occurs: 1&4, 2&3, 1&4, 2&3 ...  so injectors will fire 1, 3, 4, 2 ... or as you don't have the sync pulse from the cam the engine may be firing in the sequence: 4, 2, 1, 3 which isn't a problem as the ignition still remains: 1&4, 2&3, 1&4, 2&3 and the injectors will still fire onto closed valves.

Does that make any sense?

[Arjan]

ah right,I understand!  I will do without cam sensor.
is this called semi-sequential injection?

[rob@vems.co.uk]

As I understand the terms:
Batch is when all are fired together 1,3,4&2.
Semi sequential is where pairs of injectors are fired 1&4, 2&3. 
Sequential is when they're fired individually. 
And IIRC timed or phased is when they're fired at specific degrees during the cycle, this usually requires an injection start map and would be beyond the ability of most of us DIY'ers to tune.

There's a long running argument with claim and counter claim that timed sequential gives more power and better emissions than sequential, one thing for sure is that it gives better HC and CO emissions, but the power thing is is proven and disproven daily it seems.

For the likes of us Wasted Spark and Sequential ignition is more than good enough.

[gunni]

batch is more like "banked" injection.

for instance the bmw 6cyl´s run 1-2-3 , 4-5-6 wired together.
not sure what to call it when all the injectors are opened together.

[SamSpade]

Follow up question on sequential injection ...

When does VEMS fire the injectors during the 4-stroke cycle?  Does it start firing each injector at a fixed point of the cycle or does it end firing at a fixed point?