Hey all, First off I have an AUII falcon with a mixer ring system that i'm not entirely happy with (It can be fixed, but it'll still be a mixer ring - lpg injection sounds much better to me).
I was wondering is it possible to run LPG injectors off the stock ECU, with a J3 chip for dual maps (one petrol, one gas - this should also make it possible to advance the timing as the AU runs EDIS). Obviously there'd be a need to rig up a switchover circuit to transfer the injector pulses from petrol to LPG.

As an aside, i've noticed a few other forum members fitting there own injection systems and getting it certified, I would much prefer to mount my own injectors and hosing and then get it certified - all the tank, mixer and service lines wouldn't be touched. How does one go about getting it certified, and more importantly whats a ballpark figure for this?

Thanks, Thomas.

not possible off the std ecu as the lpg injectors are low impendance injectors,
you will need an LPG ecu, or suitable injector drivers for the lpg injectors.

Building injector drivers are easy using the LM1949 chip for example. So that part wouldn't be a problem. Would there be any other reason why what i'm suggesting wouldn't work?

Thanks, Thomas.

LM1949 is a 4:1 driver and wont work with some LPG injectors such as magic jet and valtek - im running magic jet injectors on a cleveland, and regardless of the specs they give you these injectors need min 4 amps peak and 1.3-1.5 amps holding, They would not stay open with 1A and 1 bar rail pressure. It depends on what injectors you plan on using and the specs of those injectors.

Most LPG solenoid type injectors need a longer opening time than your normal fuel injectors, also your fucntions such as cold start are completely different with lpg, you also need to adjust the fueling off rail pressure and rail temp for accurate fueling. Much better using and ecu designed for gas, it will save you a lot of messing around in the long run

Things like cold start can be easily dealt with (by starting on petrol - illegal to start on gas anyway?) and surely the longer opening times can also be programmed out in the second tune? Its just I figured the stock ecu would be far better due to a lot of the hard work already been done for you such as very little need for additional wiring + the manufacturer spent a lot of time getting the tunes perfect (easier to get engineered too), plus while your at it the j3 can control the auto box (I know the lpg ecu is separate - I just much prefer all in one).

In terms of the injector circuitry the LM1949 seems pretty configurable so it should be relatively easy to modify to handle higher currents (the current is held by the external transistor - which can be heatsinked and/or upgraded). I'm pretty confident with electronics (Mechatronics engineering student - plus i've done a bit of "hobby" electronics).

66 coupe, don't take this as me ignoring your advice, in fact your last post in particular has been very helpful, but i'm just searching for options as to whether or not this can be done.

Thanks, Thomas.

There are guys out there that have LPG injection working with a MegaSquirt ecu setup. Might want to lookup what has been done & see if the info on the hardware is helpful at all, ie, in regards to injectors & drivers for the injectors.

As for starting on LPG, I don't see why it would be illegal, considering old mixer systems can do it. My Easyjet system has a function to start on LPG all the time, but until the car warms up a bit it really runs like a pig, hence why it is standard configured to start on petrol, run for a set time & then switch over when coolant is hot enough. It's all to do with mixture control.

Cheers

ToranaGuy

im using megasquirt with SVI on a 351c (bank fired lpg will not work with a single plane intake for those with V8's) and have been for over 6 months. I have had to do my research and development (some still ongoing) because unfortunately there is not a lot of info out there for SVI setups. A lot of it is trial and error, and a lot the issues you face is dependant on what hardware you intend to use.
Theres only a handful of people worldwide with DIY SVI setups as most kits come with their own ecu's, and the other issue is here in aust LPG seems to be closed industry and you wont get a diy setup complianced.

There are no p&h drivers available off the shelf that will sucessfully run lpg solenoid rails, I have tried (so has dan from cletis) I think he gave up on p&h altogether, im running modified p&h drivers but also with series resistors because of what my injectors require to operate correctly.

You can start on LPG that is no probs and people have been doing for decades, but cold vapor is more dense than hot vapor so you need to pull fuel out when it is cold as opposed to petrol where you need to add it. This is where your rail temp sensor comes in. A table with rail pressure vs correction% easlily solves this issue.

Also depending on your converter, you will probably notice pressure fluctuations between a full and empty tank, and a hot and cold day. this is where your rail pressure sensor comes in so you can correct the fueling, on my setup i see variations of upto +/- 15% in fueling.Although at the moment im not running rail pressure and temp sensors (too lazy to install them as its my daily car), instead im running PID closed loop right from idle, with a wideband which looks after it all until i get the sensors in and connected.
Latest MS firmware supports all this, along with specific dual fuel switching control, seperate fuel, spark, afr tables and injector parameters for each fuel.

However, theres no harm in trying to get it all working with a stock ECU, and it will be a great learning experience for you, if you do decide to go the MS route and want some help just yell out

After all the stuffing around, is it going to be worth trouble when there are any number of plug and play LPG systems for your AU that will do every thing you need it to do.
Considering the likes of Emer monitor long and short term feul trims through the OBD port giving the LPG ecu ability to adjust as needed I can't understand why you want to re-invent the wheel.

I can understand to a degree with something like 66coupes setup. But even then I beleive it may be easier to fit all the needed parts from an EFI windsor to alow you to just plug and play an off the shelf LPG ecu. Although I don't know the full details of his engine.

66 coupe, thanks again for the reply. I'm curious you say getting a DIY system complianced is next to impossible yet you have a megasquirt setup - how did you go about getting it complianced? (assuming you did ). Incidentally megasquirt was my first thought but I thought using the stock ECU and a J3 would be easier/less work (apparently not - doesn't phase me, i've always wanted to try megasquirt plus it'll give me a lot more options).

On a practical note, you say that you are using p&h drivers with resistors, in theory can't this just be adapted to the stock ecu anyway - as the megasquirt would in theory drive the injectors in the exact same way as the stock one? Also don't SVI systems have a pressure regulator just like a normal injection system?

Tickford, as an engineering undergraduate I love "stuffing around" especially when it comes to engines and ECU's and things that aren't normally designed to work together . I understand there are a large number of SVI systems around (some quite cheap too) but they don't seem very flexible - i'd also like to try and optimise the LPG (spark advance mainly) which would be a bit of s**t around with two seperate ecus - plus i'll need the ecu for the auto box.

I'm yet to see an LPG ECU that plays with the spark maps at all. They may exist out there, and if they do, please show me, i'm interested!

Would be easy enough to get a decent LPG SVI system installed on-top of the factory ecu & run dual fuel, and then run 2 setups on a J3, when you switch to LPG with the LPG ecu, use that switch to trigger a swap of program on the J3, and setup the correct spark advance there.....

Cheers

ToranaGuy

MS ecu dual fuel options - covers everything you want/need

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Hey 66 coupe, i'm interested to know how you went about compliancing your setup/what was involved as i'll most likely find this to be the most irritating/tedious part of the whole thing. And I know megasquirt can do what I want, but so should the stock ECU - but still worth considering.

Also if you can give me any info regarding your injector drivers that would be muchly appreciated.

Thanks, Thomas.

the car was already complianced with a mixer setup, but depending on each state, there are different rules. Most times it just needs to be re-inspected when changes are made, however a new install needs to be complianced by a gas fitter, which usually wont put the plate on if they didnt do the work / supply the hardware.

email me re the drivers.. but keep in mind you need to work out which injectors / solenoid rails you are going to use first, to determine what is required by the drivers

Ok, so I have a mixer system complianced already - anyone know the laws regarding changing the front end of the system for NSW (or where I can find them)?

I had my EL 4.0L converted to lpg vapour injection 12 months ago. Newgas at Taren Point http://newgas.com.au/ fitted the whole system to run duel. Petrol start warmup for the converter to get up to temp.
The new injector bank went over the top of the petrol fuel rail and I used a 12mm manifold insulator between head and BBM to tap vapour nipples into each runner intake.

I just finished fitting the 1673 Wade cam today and Jason from TI Performance is sending me a custom tune to suit.
The lpg has an independant ecu that works in sync with the ford ecu. The lpg fuel map reads the existing petrol map but adjusts the lpg map based on the petrol one.

So, all I need to do now is tune the car with the new cam as best as possible on petrol with the new chip, then switch over to gas and modify the lpg fuel, based on the petrol map. That way I should be getting the best out of both systems which wasn't possible with most of the older style aftermarket dual systems.

I'm pretty sure the lpg ecu wasn't anything fancy either as the whole conversion only cost $3900
He's got a dyno aswell which helps tune it in properly.