LPG on Vems Low-z

[lost]

Does someone here runs LPG injectors directly from VEMS, i want to install hana 1.3ohm on low-z board.

Question is how to use LPG MAP and temperature sensor to measure gas pressure and set it up in vemstune.

And is it possible to switch from LPG to petron injector while engine is running if they are connected in parallel with each other and i switch +12 to them.

[Kamuto]

Does someone here runs LPG injectors directly from VEMS, i want to install hana 1.3ohm on low-z board.

Question is how to use LPG MAP and temperature sensor to measure gas pressure and set it up in vemstune.

And is it possible to switch from LPG to petron injector while engine is running if they are connected in parallel with each other and i switch +12 to them.

I think there should be no problem at all with it, using some anytrim channels with lpg temp + lpg pressure for corrections, and dual maps with output which will switch injector feed relay from lpg to petrol injectors

[VEMS]

Hello Lost,

Running LPG and Gasoline injectors from the v3 and switching is the 12v (and map) when switching in between supported; I also have an application like this on my own car.

But there is one important requirement, you will have to fit diodes inline from each 12v to each of your injectors (example if 4 cyl -> you need 8 diodes) for both the gasoline as well as the lpg injectors to be able to switch the positive over without problems.

Best regards, Dave

[lost]

Hello Lost,

Running LPG and Gasoline injectors from the v3 and switching is the 12v (and map) when switching in between supported; I also have an application like this on my own car.

But there is one important requirement, you will have to fit diodes inline from each 12v to each of your injectors (example if 4 cyl -> you need 8 diodes) for both the gasoline as well as the lpg injectors to be able to switch the positive over without problems.

Best regards, Dave

What type of diode i need to use inline (series) for every injector with gasoline lpg?

30V transient diode
18V unidirectional transient diode
BY399 3A fast diode

I need to order from webshop...

Thanks!

[VEMS]

Hello Lost,

For LPG injectors you need:  by600-5, fast diodes 5A. Not available in webshop, but DigiKey (or other like arrow, mouser) surely has them.

Make sure you order the double amount + some extra, example: if you have 8 cyl you (with 1 injector per cyl) you'll need minimum 16 diodes + some spares.

Best regards, Dave

[fphil]

But there is one important requirement, you will have to fit diodes inline from each 12v to each of your injectors (example if 4 cyl -> you need 8 diodes) for both the gasoline as well as the lpg injectors to be able to switch the positive over without problems.

+1

[lost]

I have diodes, but what about flyback wire...

[lost]

Kamuto suggested i connect both flyback and +12v to relay pin 30, and then switch both at the same time between two injector sets.

(If i connect flyback to both lpg and petrol injectors thet both sets would get +12 all the time over flyback wire...)

Can it be switched while engine is runnig?

Does anyone has setup like this one to confirm.

[lost]

I allready have config switch, if config#2 is for LPG could i use one output for relay that switches +12/flyback to LPG injectors?

So this relay would be active only when i switch config#2

[Kamuto]

I allready have config switch, if config#2 is for LPG could i use one output for relay that switches +12/flyback to LPG injectors?

So this relay would be active only when i switch config#2

yep

[lost]

If i install low-Z extension inside vems for all 8ch, and remove existing TS diode from vems, connect flyback wire to extension board.

Would flyback and +12 be ok like this? Switching flyback and +injector supply when i switch to config2 and activate relay.

Does anyone has it set up like this ?

[VEMS]

If i install low-Z extension inside vems for all 8ch, and remove existing TS diode from vems, connect flyback wire to extension board.
Would flyback and +12 be ok like this? Switching flyback and +injector supply when i switch to config2 and activate relay.
Does anyone has it set up like this ?

Hello Lost,

Yes i have a setup similar to the picture you posted on my daily driver, but i have flyback wire connected to switched vbatt (wire 15) not wire 30 to have all power to VEMS v3 off when ignition key is off.

Best regards, Dave

[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?

Thank you Dave!

[VEMS]

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

[lost]

Second version, here lpg injectors are connected to low-z extension board flyback wire, and gas HIGH impedance injectors stays connected as before via 30v TS diode to vems board ec36 pin 12 (classic setup)

Could that work?
One config would be with PWM one without.