Subpage of Base setup menu

Injector voltage compensation strategy

• Traditional - the ecu calculates the added deadtime based on the input variables below.
• Simplified - the ecu looks up the deadtime from injector deadtime table (interpolated by VBATT).

Simple Injector Voltage Compensation

Injector datasheets sometimes contain injector opening values like +1000..1500 usec in function of VBATT. These values usually neglect (appr 800 usec or more) injector closing delay and are, without applying this offset, insufficient to directly predict reasonable additive values for injector-pulsewidth. When substracting the typical 800 usec offset for each deadtime voltage curve point they are however a very good value to use as a starting point.

• Injector deadtime table 8/10/12/14/16v
  Deadtime values for your injector at the respective voltages, when in doubt use 720 usec, 540 usec, 360 usec, 180 usec and 0usec (for 8V, 10V, 12V, 14V and 16V respectively). Take care changing deadtime values means VE table will need to be retuned!

Further live mapping of the dead time is possible and this is how to do it:

• 1. Warm up the engine and get idling as steadily as possible at lambda 1.0, make sure the lambda target map in idle area is also set to lambda 1.0, retuning VE table where needed.
• 2. Change the lambda target section at current cursor position (adjust a box of neighbouring cells also) to 0.8 and press BURN
• 3. If the measured lambda becomes richer then 0.8 you need longer dead time, if it's lean then you need shorter dead time so change the value accordingly by 50%
• 4. Put the target back to 1.0 and press BURN
• 5. Adjust VE map until it idles at 1.0
• 6. Go back to step 2 and repeat until changing the lambda target always results in the measured lambda being the same. As you get closer to getting correct lambda values all the time make smaller changes.

NOTE: When increasing the dead time during this calibration the mixture will become richer so when putting the lambda target back to 1.0 you will need to remove fuel. If you need to lower dead time the mixture will become leaner then 1.0 when target is set back to 1.0, ideally before doing it give the VE map a little bit extra so that the engine doesn't see higher then 1.1 lambda as it might stall on you.

Why is correct deadtime setup important?

Engine will run properly at all battery voltages, the VE table will be more "correct", all fuel corrections will have the effect they are designed to have, EGO control will be more accurate and the engine is easier to map on all accounts.
Badly setup injector deadtime might result in bad VBATT (transient) response on newer actively managed (load based) voltage regulated alternators, crazy low VE-valley when deadtime is too high or high peak VE around idle when deadtime is set too low.

Traditional Injector Voltage Compensation

• Injector Open Time @13V
  Set to 0 ms, in most cases (although the injector has an opening delay, but it also stays on longer because of the closing delay, see above). With too high value there will be a VE-valley around idle.

• Injector Battery Compensation
  typically around 540..600 usec (added at 7V and subtracted at 19V, interpolated in between. With 540 usec / 6V = effective slope is 90 usec / Volt)

• Injector Effective Rampup
  How fast the injector reaches full flow after opening (the slanted part of the curve), typically 100-400 usec. 200 usec might be a good starting value if measurements about the given injector are not available.

• Injector Rampup Voltage Compensation
  Enter 4080 us.

Injector PWM Duty Cycle
If you ecu is fitted with 30v Flyback set to 100% to disable the function, when activeFlyback or Low voltage flyback is present it can be enabled when Direct PWM ETC Control is not used.

Injector PWM Peak Time
If you ecu is fitted with 30v Flyback set to 25.5 ms to disable the function, when activeFlyback or Low voltage flyback is present it can be enabled when Direct PWM ETC Control is not used.

Divider
Open injector only every 'Nth' ignition event, typically 1 injector is wired to 1 injector output which results in a setting of '1' and sequential injection.

Number of primary injectors
Normally the number of injectors you have. If you are running staged injectors, the number in the primary set.

Fire Banks While Cranking

• Simultaneously - open all primary injector groups during cranking.
• Individually - opens the primary injector groups sequentially during cranking, just like normal running engine.

Cranking Fuel Divider
When fire banks while cranking is simultaneously pulsewidth width needs to be divided by the amount of extra enabled injectors compared to individually, normally number of cylinders, for semi sequential enter number of cylinders/2.

To get an advanced view of each of the settings effect on pulsewidth take a look at Pulse_width expression grid (available in Injector calibration or Calc model group).