Injector dead time

I am having problems will eletrical load. In my injectors setting, it looks like the tuner did not put in the injector dead times. Stock vr6 injectors at 4 bar, ecu is VEMS. Any thoughts?

Doesnt look like it

If he tuned it, and its like that, you are going to have to retune im pretty sure.

It's set to traditional...not sure what that would mean...maybe he tuned it into your pulse widths? Not really in with this ecu.

Are you having afr changes when the voltage changes? Like, headlights on, windows, etc.

ive asked my injector guy for a dead time list, be back at you shortly.

Thanks for the fast reply!!! I am pretty sure the afrs are changing because once the rad fans come on, the motor wants to stall.

im wondering if somehow its using the values below somehow to do it. here is kind of a tutorial

http://vems.hu/vt/help/v3/v3_injector_settings.html

Either way, if you are having issues, trying a table style correction would be a good idea. It would be nice if you had a wideband to verify that your afrs are going whacky when electrical load is on.

I do have a wideband, I didnt look at it when it was trying to stall. Ill have another look this weekend.

I have read that link, still trying to figure out what they are saying lol

This part

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.

It appears to me that by using the battery compensation and ramp up, it draws a slope between them?

maybe Andre can chime in, lol. I've honestly never come across this type of dead time compensation.

Im at a lost as well. Thanks for the help.

VEMS isn't an ECU I'm familiar with and I've never seen dead time compensation dealt with like this so advising you here is going to be tricky. Based on the fact the dead time values are the same at each voltage (4080 µs) it appears the table hasn't been filled in to suit your injectors. If you make any changes here, it will effect your tune although the change will be more prevalent at low load/idle than it will be at high load/rpm.

While the rad fans switching on can cause the voltage to drop (which can be a problem), it will also apply more load to the engine which tends to pull the idle speed down too. What this means is that even if your dead time is spot on, you can still have problems with the engine wanting to stall when the fans drag the rpm down when they switch on. To deal with this often the ECU will provide an idle up when the fans or air con switch on.

A good test to see how stable the AFR is across changing battery voltage is to pull the alternator fuse at idle. This should drop the voltage from around 14 to around 12-12.5 without affecting the load on the engine and hence the idle speed - Try this and see how the AFR changes (if the dead time is on point, the AFR will stay stable). You can go further by switching on loads like the headlights and heater/blower to drop the voltage lower again.

Thanks Andre. Ill give it a shot and report back.