I own a 1996 EF Fairmont and am in the process of installing a LPG conversion kit from an EL Falcon. I used to work in the CNG business so I have a good understanding of the mechanical parts of the kit. I have the complete kit including the ECU from the EL.

To get an LPG kit to operate properly I'm going to need to do two things.

1. Turn off the petrol injection.
2. Set the timing appropriate to the LPG kit

If I can install the EL's ECU into the EF then this should solve both of these problems. The obvious consequence is that the EL's petrol map may not be ideal. However I'm not intending to use Petrol much once I've got the LPG system working.

Can I just plug in the EL's computer work in the EF? Will it burst into flames if I just try it?

I think you will find that the Ef and El computers have different numbers of pins on the connector and are not interchangable
Station-rat

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Last edited by blackjack_original on Fri Jun 06, 2014 3:59 pm, edited 1 time in total.

Ok. That means I'm back to finding an alternative way of advancing the timing a little or just leaving it where it is and accepting it as a bad compromise.

I take it that the best method of advancing the timing is to rotate the ignition pickup (distributor substitute) by a few degrees and then use an electronic gismo to retard the timing again back to the correct setting for Petrol. Presumably the retarding could be done by the LPG computer if I had the right information.

This leads me to my next question. Does anyone know how the injectors are disabled through the LPG system? At the moment I am assuming that it's the three wires that used to connect to the large rectangle plug on the EL.

I'm planning a trip to the library this week to see if I can get my hands on some sort of wiring diagram. Failing that I will probably have to go and pester Ford too see if I can get enough information from them.

Doesn't the EF automatically advance it's timing when needed?
How come you need the ECU from the gas car? As I thought LPG was like a carby system and didn't rely on the ECU.

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Last edited by blackjack_original on Fri Jun 06, 2014 4:00 pm, edited 1 time in total.

I have a slight advantage being in New Zealand. The laws are less striict so I can get away with using an open loop system. I did have an oxygen sensor driven power valve on a previous car which ran on CNG.

As for the timing, I realise that whatever I do is going to be a compromise but it's still going to be a hell of a lot cheaper than Petrol. I figure I can rotate the timing pickup (distributor substitute) by a few degrees giving me some extra spark advance. If I fill the petrol tank with Unleaded 96 instead of Unleaded 91 then the extra advance isn't going to be a problem on Petrol. I could also get one of those gismos that they used to use in the '80s on CNG cars here which retard the timing back to normal for Petrol operation. The curve on LPG would still be wrong but a bit more advance is a better compromise.

Another option would be to fit an aftermarket car computer to do the ignition timing but I don't think that will have a good enough economic pay back to be worth the trouble.

Within an old post "advancing timing on an EL" you will find some comments from GreenMachine which describe the distributor substitue on EF's.

So, to advance the timing on your EF, you need to change the relative rotational position of the crank angle sensor on the front of the engine relative to the crank shaft toothed cog - not the cam angle sensor on the side of the engine block
Cheers Itchione