LPG on Vems Low-z

[Kamuto]

no

[lost]

Got this from: http://www.vems.hu/wiki/index.php?page=MembersPage%2FDamirMuha%2FLPG (image was lost on imageshack)

Dont get it how flyback and vems inj out are connected between lpg and petrol injectors on this drawing?
And is zener 50v diodes for protection, thats missing on my drawing.

vs

[lost]

I have update drawing, now injector switching relay pin 30 (flyback and +12) is supplied via key-on ignition relay that supplyes vems e36-pin25. (turns on vems).
Could you check if its ok for injector switching relay to be controlled with VEMS output, and does this relay needs diode between pin 85 and 86?

Yes, switching the relay from v3 is perfect, that's what i do on my car;

You can use the fuel pump output to switch the relay:

• in map A (gasoline): the fuelpump function switches the normal fuelpump relay.
• In map B (LPG): configure the fuelpump function to turn on the gas relay (this powers LPG injectors but also gas shutoff valve on pressure regulator). The fuelpump function has special handler that switches previous output off and new output on when difference in output configuration is detected between map A/B take care only fuelpump function output does this.

Best regards, Dave

That is great for LPG swithing.
What about:


If left like this is switches from petrol to lpg for 2.88 seconds. And then switch back to gaseline, and then activate relay again and switch to LPG when cranking?

Do you use 0 seconds in this map?

I'm also intrested what settings for PWM on Gas and LPG injectors to use with extension board, i have barracuda (HANA) lpg injectors.

And most important thing, do you have LPG reducer valve + connected to relay pin 87 (LPG flyback wire) like on picture below and is diode needed on that lpg valve/coil.

Thanks.

[VEMS]

Hello Lost,

If left like this is switches from petrol to lpg for 2.88 seconds. And then switch back to gasoline, and then activate relay again and switch to LPG when cranking?

Do you use 0 seconds in this map?

No, since the engine is not stopped on map switch A->B (or reversed) these settings do not activate, use normal settings

I'm also interested what settings for PWM on Gas and LPG injectors to use with extension board, i have barracuda (HANA) lpg injectors.

And most important thing, do you have LPG reducer valve + connected to relay pin 87 (LPG flyback wire) like on picture below and is diode needed on that lpg valve/coil.

Well that depend on your LPG injectors, i use Prins injectors if i remember correctly i use 3msec peak-time and 40% hold. Determine the settings for your LPG injectors when the engine is running, in this case lower is better for both (lowest setting for peak and hold, where injectors still open reliably; you can start from my settings).
Yes i connected the LPG shutoff valve to the switched LPG injector supply.

Best regards, Dave

[lost]

Thanks to everyone for help,
Car now starts , i had to double reqfuel- now 20ms and double VE map (90 at idle) values to get it to idle at lamda 1.
EGT is spiking at 300- 1000c at idle. depending on cycles.
I need to drill out nozzles from 1.5 to 2.4mm, hope it gets better then.
I have it connected like this:



Is it possible to switch lpg/gas when engine is running?
Without burning fets  (relay switching).

And is there any way to convert lpg injecor flow to cc that vems uses to calculate req_fuel.
I have six 130nL/min lpg injectors.

[lost]

Is there a way to determinate best PWM settings, if i cant see any change when chaning from 35 to 30%  and 3 to 2ms.

Engine idles at 0.9 lambda if i lower VE then it dies, its on 900rpm...
What to look at? Is lambda different on LPG?

[lost]

Still need info how to determinate correct pwm settings for new low-z injectors.

I got high consumption , very high egt, 1200c on throttle, lambda is good on power but its always rich 0,85-0,9 on idle or engine stalls.

[Kamuto]

Still need info how to determinate correct pwm settings for new low-z injectors.

I got high consumption , very high egt, 1200c on throttle, lambda is good on power but its always rich 0,85-0,9 on idle or engine stalls.

low timing maybe?

[lost]

Still need info how to determinate correct pwm settings for new low-z injectors.

I got high consumption , very high egt, 1200c on throttle, lambda is good on power but its always rich 0,85-0,9 on idle or engine stalls.

low timing maybe?

tried to add 10deg to timing with no change.

Could you help me how to calculate req_fuel for lpg injectors, they are 130 nL/min that would be 1300cc so it makes no sense to me now they have nozzles for around 35hp per injector.

I'm also not sure how to get correct PWM settings, it works with 15% it works with 35% ,  i dont see any change, it dies below 1.6ms and idles same with 1.6 or 3 ms.
I'l post log if i found upload/hosting site.

[lost]

Can anyone write short info on how to calculate reqfuel for LPG and how to setup PWM values for lowZ injectors.

Just a few pointers.