OMVL dream xxi. do i need lambda?

[DieSchnelleKafer]

Hi Guys. so i just purchased an omvl dream xxi kit: 8CYL autogas kit OMVL Dream XXI-N, HP Reducer, Gemini (http://www.lpgshop.co.uk/8cyl-kit-omvl-dream-xxi-n-omvl-hp-reducer-gemini/)

Apart from the LPG ECU taking readings from a few rover ecu wires connecting to the obdII port, it says that fitting a lambda sensor to each bank of cylinders is optional. i have to ask if it is worth it? because it means using 4 lambda sensors in total! crikey.

is there a possibility of using the 0-5V reading from the existing lambdas?

also, i cant seem to get a clear answer on this question, but what are the well known spark plugs to use for a LPG 4.0 thor v8? 2004 d2a.

[bee utey]

Most sequential LPG systems only use oxygen sensors as a reference that can be seen on the tuning screen. They play no part in the actual fuelling. The ones already fitted pre cat are the ones usually tapped into. The most important inputs for the LPG ECU are the petrol injector on times, sourced directly from the petrol injectors themselves. OBD2 input (fuel trims) allows the LPG ECU to retune a small amount once the basic map is set. It doesn't replace the need for a thorough setting up of the base map, especially on WOT.

On spark plugs, a good rule of thumb is to use plugs 1 to 2 heat ranges colder than stock, and 30% less gap. Avoid multi gap or surface gap plugs that can't be adjusted. Bosch platinum, Brisk silver and NGK iridium all see to be good although plain plugs work well too. They are easy to check and change on a LRV8 so annual removal is no big deal.

[Pedro_The_Swift]

AFAIK,, (which is admittedly not far)
The Thor ECM(which gives all tuning signals to our OMVL piggyback) will adjust/tune itself to run properly on LPG and PULP, it adjusts the mixture every time you start it and every time it switches fuel,, if there are no O2 sensor inputs(which include correct ECM inputs from the heater paks and V output/signals) the ECM has no way of adjusting its tune to Lambda.
and will run up to ****.

no you dont need 4,,
but you do need two that work.

[DieSchnelleKafer]

Most sequential LPG systems only use oxygen sensors as a reference that can be seen on the tuning screen. They play no part in the actual fuelling. The ones already fitted pre cat are the ones usually tapped into. The most important inputs for the LPG ECU are the petrol injector on times, sourced directly from the petrol injectors themselves. OBD2 input (fuel trims) allows the LPG ECU to retune a small amount once the basic map is set. It doesn't replace the need for a thorough setting up of the base map, especially on WOT.

On spark plugs, a good rule of thumb is to use plugs 1 to 2 heat ranges colder than stock, and 30% less gap. Avoid multi gap or surface gap plugs that can't be adjusted. Bosch platinum, Brisk silver and NGK iridium all see to be good although plain plugs work well too. They are easy to check and change on a LRV8 so annual removal is no big deal.


I was hoping you would find this thread~!

thanks mate that answers my question. I have a separate diagnostic o2 sensor i can use when the tuning stage comes. As far as the plugs go i will use that information you provided to find the suitable bosch plug. cheers

[DieSchnelleKafer]

Most sequential LPG systems only use oxygen sensors as a reference that can be seen on the tuning screen. They play no part in the actual fuelling. The ones already fitted pre cat are the ones usually tapped into. The most important inputs for the LPG ECU are the petrol injector on times, sourced directly from the petrol injectors themselves. OBD2 input (fuel trims) allows the LPG ECU to retune a small amount once the basic map is set. It doesn't replace the need for a thorough setting up of the base map, especially on WOT.

On spark plugs, a good rule of thumb is to use plugs 1 to 2 heat ranges colder than stock, and 30% less gap. Avoid multi gap or surface gap plugs that can't be adjusted. Bosch platinum, Brisk silver and NGK iridium all see to be good although plain plugs work well too. They are easy to check and change on a LRV8 so annual removal is no big deal.


HI Mate, it seams you are the bloke to go to regarding LPG around here.. i have another quick question.. I am about to wire in the omvl/aeb ecu for the lpg conversion. I need a licensed workshop to plumb the high pressure line from the tank to the reducer. I need to know if the ecu automatically defaults to running on petrol injectors when you initially start the car for the first time? If it automatically defaults, it means that i will be able to drive the car to the installers to get the gas line fitted. i hope what i am asking is clear.

[bee utey]

HI Mate, it seams you are the bloke to go to regarding LPG around here.. i have another quick question.. I am about to wire in the omvl/aeb ecu for the lpg conversion. I need a licensed workshop to plumb the high pressure line from the tank to the reducer. I need to know if the ecu automatically defaults to running on petrol injectors when you initially start the car for the first time? If it automatically defaults, it means that i will be able to drive the car to the installers to get the gas line fitted. i hope what i am asking is clear.
Assuming there is nothing loaded on the gas ECU but a base programme it will be on petrol out of the box. Regardless, even it was fully programmed the MAP sensor would show a low LPG pressure and default to petrol operation. The engine being below change over temperature will hold petrol on too. Pulling the main fuse will also result in petrol operation. Finally it helps to have the engine fully assembled when you start cutting the injector loom so that you can test each injector cut as you solder it up, therefore catching any mistakes you make as they happen.

Also you have a change over switch, check that the petrol operation is selected. Reading the instructions may help. :)

[DieSchnelleKafer]

Assuming there is nothing loaded on the gas ECU but a base programme it will be on petrol out of the box. Regardless, even it was fully programmed the MAP sensor would show a low LPG pressure and default to petrol operation. The engine being below change over temperature will hold petrol on too. Pulling the main fuse will also result in petrol operation. Finally it helps to have the engine fully assembled when you start cutting the injector loom so that you can test each injector cut as you solder it up, therefore catching any mistakes you make as they happen.

Also you have a change over switch, check that the petrol operation is selected. Reading the instructions may help. :)

Thanks man. I assume when you say to have it fully assembled, you mean start the engine and check for faults after intercepting/cutting/soldering each new wire? i would understand the sense in that.

manual? no.. i only have a vague pdf that describes the simple operation and wiring diagram. it does not go into the finer details of operation. BTW here is my build thread, at the end of the page i have shown the layout of the injectors etc. http://www.aulro.com/afvb/projects-tutorials/235630-project-roverkill-d2a.html