LPG wiring

[justinc]

Ok, here is one for those who are familiar with LPG installing.


I have a D1 in at work ATM, it has hot wire EFI, and is an early 3.5 model.(1992)

When switching from petrol to gas, while the engine is running, it removes the signal from the Airflow meter to the ECU. I know this bacause my Rovacom tells me 0 airflow input when running on LPG.

The problem occurs when switching to petrol on the go, the ECU logs an AF meter fault, and belches black smoke etc until, as some are aware, you switch off engine for about 10 seconds, and the ECU resets and all is good again in the world of AF monitoring.

Obviously, this is not a good scene, and I want to know can I just re wire to cancel injector pulse to both banks and leave the AF circuit alone? This has been like this for some time, as the AF meter was Kaput from having the voltages removed at short notice, and therefore being unable to 'afterclean' the wire.

Having fitted a new AF meter, I don't want this to happen again.

Any ideas? Or should I just go and re wire to remove injector pulse on LPG.
( and anyone who has done this, any pointers?)



JC

[Bradtot]

Hello Justin I have an 89 Rangie with flapper air flow on lpg/petrol and what the installer did was to switch off the injector pulses to the injectors for both banks using a double relay. He spliced into the wiring to the injectors before it went into the firewall. This has worked very well for 3 years now. I suggest doing what u suggested and leave the airflow meter alone.

Brad

[tony]

HI Justin

As said above use double relay to cut inj pulse where the inj control box is bolted to the MAF bracket you will have two big brown wires coming out of there splice into them I have done this on my other rangie and works a treat no lag switching from one fuel to the other

PS no rust at all

Tony

[100I]

JC you are the man.

The symptoms you have describe are identical on my car and I bet it's wired the same way. It has always run extremely poorly if switching from LPG back to petrol on the go, untill I reboot.

thanks


EDIT. Utemad, are you reading this?

[PhilipA]

Obviously, this is not a good scene, and I want to know can I just re wire to cancel injector pulse to both banks and leave the AF circuit alone? This has been like this for some time, as the AF meter was Kaput from having the voltages removed at short notice, and therefore being unable to 'afterclean' the wire.

Just for info AFAIK,The 14CUX is about the only ECU in the world that does not heat the MAF wires on shut down.
This is why 14CUX's hate K&N filters more than most.
Regards Philip A

[justinc]

THanks PhillipA,

Not sure why then the AF meter failed except for the possibility of a backfire at some point?

I have learnt something else about these AF meters now, Thanks Phillip!!


Just wired it up, works perfectly,

JC

[justinc]

JC you are the man.

The symptoms you have describe are identical on my car and I bet it's wired the same way. It has always run extremely poorly if switching from LPG back to petrol on the go, untill I reboot.

thanks


EDIT. Utemad, are you reading this?

Yee haa,

And it works now!!!!


JC

[sclarke]

Yep that makes sence... when i wrecked the LPG fireball disco i noticed the wiring on it....

now i know how to wire a LPG V8 injected disco.....

YAY.... i learnt something today.. the Quote is correct...