The V8 Owners Forum -

without lambda sensors ? ...
is there a way of tricking it into thinking its got them ?

ALSO .. running a 3.9 setup on a 3.5 ...dont care if it runs a bit rich i only use petrol as a standby when the LPG runs gets low ..

will it run , thats all really ? ...thankyou

Yes

If you change the tune resistor it basically ignores what would come from the lambda sensors

Ian

Hope this helps (half way down the page) http://www.g33.co.uk/fuel_injection.htm

Thankyou Guys ...
what about a 3.9 setup on a 3.5 engine ?

There's no self tuning on a hotwire - especially with no O2 sensors.
Be better to replace the ECU with a MegaSquirt. You could then dispense with the hotwire sensor - and expensive item to replace.

Having just changed from a Hotwire to a Megasquirt system there is quite a significant cost when you add it all up. ECU kit £625, Wideband lambda sensor £138, Spark plug leads £80, resistive spark plug set £16, trigger wheel balance £55 so over £900.

I also have two tune resistors - one Cat and one Non-Cat - for sale as I no longer need them (plus other Hotwire stuff but yet to sort out a proper post).

DaveEFI wrote:There's no self tuning on a hotwire - especially with no O2 sensors.
Be better to replace the ECU with a MegaSquirt. You could then dispense with the hotwire sensor - and expensive item to replace.

Thankyou Dave but i only want petrol as standby incase in runs low on LPG ...
i cant remember the last time i switched the petrol on

i have a flapper setup at the moment but its better for the LPG mixer not to have a flap in the way , and have found a cheap HOTWIRE setup

richardpope50 wrote:Having just changed from a Hotwire to a Megasquirt system there is quite a significant cost when you add it all up. ECU kit £625, Wideband lambda sensor £138, Spark plug leads £80, resistive spark plug set £16, trigger wheel balance £55 so over £900.

I also have two tune resistors - one Cat and one Non-Cat - for sale as I no longer need them (plus other Hotwire stuff but yet to sort out a proper post).

That's not a swap from hotwire, but a serious upgrade. Fuel only MS is a lot cheaper. Especially if you use a secondhand MS - same as fitting hotwire. You should be able to get an MS1 V3 for about £200-250. And the wideband O2 is optional, although desirable.

To be honest it was what was recommended as I wanted to improve my fuel consumption so was convinced to go MS2 wasted spark and coil packs. It was the extras that I was not expecting I needed. The base Lucas swap to MS kit is a lot more.

Just hope it all works.

richardpope50 wrote:To be honest it was what was recommended as I wanted to improve my fuel consumption so was convinced to go MS2 wasted spark and coil packs. It was the extras that I was not expecting I needed. The base Lucas swap to MS kit is a lot more.

Just hope it all works.

Like most things if you go to a dealer you'll end up with what they want to sell you. Doesn't mean it is the most cost effective way, though.

Even the very best MS etc installation won't give much improved MPG over what the factory fitted (in good condition) , assuming an otherwise standard engine.

Actually it was Phil at Extra EFI but the point really is that with MS you can map it to your needs and lean it down for one's driving preference. We shall see.

richardpope50 wrote:Actually it was Phil at Extra EFI but the point really is that with MS you can map it to your needs and lean it down for one's driving preference. We shall see.

I doubt you'd want to lean it down more than the original Lucas system did.

Did Phil say you'll get noticeably better MPG?

Any info on wether a 3.9 HOTWIRE will work on a 3.5 engine .. and again only as a standby ???

Thankyou

Hi
I am pretty sure someone on here quite a while ago ran the hotwire on a 3.5. I can see no reason for it not to work. All the system will do is self adjust to the lower air flow of the 3.5 engine courtesy of the AFM and assume you have an inlet restriction. Worst case fit an adjustable fuel pressure regulator and lower the fuel pressure about 10%.
Best regards
Mike

Thankyou Mike