Auto electrician help needed, for relay wiring.

[Rovernaut]

My Disco is on LPG .there are 3 relays that control the starting of the system plus the Airod solenoid connector.
I have been trying to figure out why my starting on LPG is difficult and believe the relay thar controls ther Petrol start injection was probable cause.
The problem is I have some how mixed the wiring up. I hope some of you might be able to help. I'll run on LPG once started but when I switch to petrol the starter solenoid still stays engaged after the engine has started and is running. This doesn't happen when it's running on LPG.
I suspect that I have a short somewhere whilst it's running on petrol.

2 relays are 5 pin ( change over relays?) with the 87 'A'.
The other is a 5 pin standard relay with 2 87s.
On one relay all the terminals are used and on the other 2 only 4 terminals are used, (the centre terminal is not used)

I have a 3 pin rocker switch on the dash that is the LPG /petrol change over switch.
I believe when LPG is selected and ignition is turned to start a relay acivates the petrol injectors to enable the engine start, then deactivates and the LPG system takes over.
When petrol is selected the relays by pass LPG and allow full petrol running.

does any one have a systematic wiring diagram that could help me to correct my setup?
Any help appreciated.

[ORSM45]

the 87's are the same terminal as each other (not sure what the A means), just for looping to other relays and stuff. i think.
sounds like the starter relay is running from the petrol relay. so power is given to the starter when switched to petrol.
what sort of switch do you have? 3 position. etc.

[ORSM45]

did you get the wire from the ignition ('on'), and from 'start' to run the petrol relay? meaning that its linked therefor the 'on' will also become 'start'

then on the gas only got a 'on' position wire? so when switched to 'start' the gas relay doesnt get power?

get a multimeter and check whats goin on when in different switch positions

[Bluey]

My Disco is on LPG .there are 3 relays that control the starting of the system plus the Airod solenoid connector.
I have been trying to figure out why my starting on LPG is difficult and believe the relay thar controls ther Petrol start injection was probable cause.
The problem is I have some how mixed the wiring up. I hope some of you might be able to help. I'll run on LPG once started but when I switch to petrol the starter solenoid still stays engaged after the engine has started and is running. This doesn't happen when it's running on LPG.
I suspect that I have a short somewhere whilst it's running on petrol.

2 relays are 5 pin ( change over relays?) with the 87 'A'.
The other is a 5 pin standard relay with 2 87s.
On one relay all the terminals are used and on the other 2 only 4 terminals are used, (the centre terminal is not used)

I have a 3 pin rocker switch on the dash that is the LPG /petrol change over switch.
I believe when LPG is selected and ignition is turned to start a relay acivates the petrol injectors to enable the engine start, then deactivates and the LPG system takes over.
When petrol is selected the relays by pass LPG and allow full petrol running.

does any one have a systematic wiring diagram that could help me to correct my setup?
Any help appreciated.

ok, first as 383FJ45 said, 87 and 87a on a relay are electrically the same. this normally switched output, and the second tab (87a) allows you to turn second thing on eg one driving light on 87 and one light on 87a.

the dash rocker switch, this is three terminal on the back? would normally then have +12v middle terminal, other two outputs to relays (might be common negative so ground on middle terminal, just check with multimeter).

the starter solenoid stays on when select petrol, so you mean starter motor keeps turning over?

there are three relays, so what do they go to? is there any fancy electronics box as well or everything operates from these relays?

bit more info might help, can you post any pics?

[Rovernaut]

My relays are under the dash on drivers side.
The rocker switch is a 3 terminal. centre is +pos, left terminal is the LPG and right is Petrol.
The Relay with the 87a, is a change over switching relay.
When engerised it switches so the one terminal is open, when not it releases and closes that terminal and then bridges another. See previous pics of relays. You'll notice the different connections.
I reckon your right that the starter and fuel pump have a wiring fault.
seems strange , but i remember had this problem just before i mucked the wires up.
on the Airod solenoid control, The coil terminal is not used in ( EFI systems)

[Bluey]

I reckon your right that the starter and fuel pump have a wiring fault.
seems strange , but i remember had this problem just before i mucked the wires up.

so you had this problem b4 or only since you swapped wires around?

haw many wires did you swap around? assuming common and switch pos for relay coil still same, leaves only input (normally +12v) and outputs (87 and 87a)

idea: disconnect output wires and connect up one at a time.ie just to get running on petrol, does this fix fault??? if one +pos wire to activate injectors, hard wire this. does it work? now work out relay to achieve this then wire up injectors. similar thing for gas

[ORSM45]

i get what ya mean with 87, 87a. when 87 is on, 87a is off. and vice versa.

so is the 87/87a relay the one that only uses 1 output?

the way i see it is fuel/gas shouldnt have anything to do with the starter, until its on start. so just follow the feeds to the relays, back and see what they are connected too.

(im not an auto elec. but i am an electrician, same shit different shovel )

so the switch is fine. just 1 wire in each terminal? (ie. 1 wire from fuel position, 1 wire from gas position. 1 wire from ignition coil feed or similar.)

[Rovernaut]

Well I think I've got to the root of the problem.
I checked all my wiring to the relays, and connections.
I found that when I 'fiddled' with the wiring the started would re engage whilst the motor was running. I checked all the wires thinking there was a short between 2 wires.
I found that when I touched the yellow wire going to the AIRROD solenoid control box that the fault appeared and the little LED light would go out and blink then come back on.
I believe that this was the fault all the time, it must have a bad connection or short inside.
I always have discounted this box as all LPG fitters I rang said, "THEY RARELY EVER FAIL!"

[ORSM45]

ah hope thats it then, sounds like you have a rare problem then