lpg system control from MS? can it be done with stock code?

[Phillblanchard]

hi guys,
just a quick one here, ive finally got the MS working like a dream on my range rover.
also fitted the lpg system ive had kicking about for ages, all charged and no leaks! (not any more anyhow ;) ).

theres 2 solenoids on the kit, these were apparently powered from a control box, which was also linked to the -ve side of the coil.

a: is the -ve coil feed for RPM measurement purposes?

2: can i control this from the MS? i obviously need to shutdown the injectors and fuel pump when switching to gas. how do i do this?

c: i was thinking of just cutting the power to the MS. would this do any harm?or would it 'spike' the cct to hell?


the original control box has gone somewhere, but i have a scrap of paper with a diagram on it of the wiring. hence im wondering how to control this!

short of having a power cut switch to the MS and another power on for the lpg solenoids, what can i do?

Current setup is: MS v3, 8 injectors alt firing, split into 2 groups of four.
if poss id like to use the lambda readout to monitor the lpg mixture and allow me to make manual adjustments as necessary to the reducer.

i dont really fancy putting the other code into the MS. pretty much scared by it! is there anything i can do with the stock code?

what can / shall i do?

Thanks in advance!
Phill.

[mitsuko]

I'ts very easy to do this .
I've run like this for years before I switched to lpg injection .

First , the lost control box is probably a petrol start system .
It automaticly starts the car on petrol , then detects rpm ( coil ) and once your rpm goes above a certain setpoint , it switches to lpg .

I used a relay with a normally open and a normally closed contact .
Std automotive 3 pole relais

Put the nc contact in the 12V line that feeds power to the injectors .
Wire the no contact to power the lpg solenoids .
Operate the relay with a switch on the dash .

Now with the relay inactive , you're running on petrol .
If you activate the relay with the switch , your injectors are powered
down , and your lpg solenoids are powered up . Make sure the fuses are adequate .

The rest of the ms remains active , so you can monitor , datalog , whatever you want .
I would not power down the fuel pump .
Let the fuel circulate , keeps the fuel rail and fpr to a reasonable temperature .


Pat

[Phillblanchard]

hiya mitsuko!
i was hoping youd be around!

so using the relay wont cause surges or spike the injector drivers?

with 8 injectors, 4 per injector driver bank, would i need 2 relays, one for each bank?
what fuse rating would you recommend?

this looks like a great idea! thanks

Phill.

[mitsuko]

Yeah well , lpg usually attracts my eye .

I doubt that there will be any issue with spikes ore whatever
Drove around like this for two years , with an automatic petrol start
controlling the relay . So I had a switch over every time I started the car .
That same legasquirt is still used , only it is used now to control both lpg and petrol injectors .

I think a single relay will do fine .
Let me take a look at the wiring diagram later on and get back to you on this .


Pat

[Phillblanchard]

ok, thanks!

Phill.

[mitsuko]

Here's a quick drawing .

Hope it makes sense , otherwise just yell .

Pat

[Phillblanchard]

Hi again!
Right firstly thanks to Mitsuko for the diagram! Ive got it sorted! works a treat too, so thankyou! ive even installed a flashing blue led to tell me when the gas is on!

the only problem i have now, is the mixture seems all to pot. it will start on lpg when cold, but definitly will not when hot.
indicating an over rich condition.
performance is terrible below 3krpm, then it takes off like a rocket!

ill get my laptop connected tomorrow, once ive sorted out the invertor to power it (laptop battery is now goosed).
Can i use the lambda sensor as a gauge for setting up the mixture?

the reducer is a BRC AT90E modello super.
there appear to be 2 'allen' head style screws on the side of it, (from the front its the right hand side.

i know for sure one must be the idle mixture adjustment, because it affects the idle speed when you fiddle with it.
dont know about the other one.

there are also 2 knurled brass sticky out things, one big one on the front of the reducer facing forwards and one small one next to the 2 adjustment screws. what are they?

if anyone knows the procedure for setting these up, please let me know! ive asked at the local Autogas place that fits BRC stuff and they wont tell me, cheeky monkeys. they just want my money! ;)


Phill

[mitsuko]

Phil , I need a few pictures of the vaporiser and the mixer , and then I can probably tell you what to do .

Pat

[Phillblanchard]

Right ive got some pics sorted now. ive put some text on them to make explanations easier

Phill.

[mitsuko]

Gee , I thought I'd seen them all .
This one doesn't look familiar at all .

The big brass thing at the bottom is either a second drygas outlet , or a sludge remove tap . Open it every time you service the car , and let the tar like substance drain out .

The knobly braas sticky out thing is probably the 3000 rpm mixture set screw . Have someone block the trottle at 3000 rpm , and then try to adjust it . Look at the oxygen sensor for changes .

If it responds , set it as close to lambda = 1 as possible , but always .
to the rich side of the oxygen sensor trip point .
If this works , use the idle mixture screw for idle adjustement .
Set it to e decent idle , regardless of the oxygen sensor .


Then repeat the 3000 rpm adjustement .

That ought to do it




Pat