Hotwire EFI Question

landrovernuts · Post by **landrovernuts** » Sun Apr 06, 2008 12:18 pm

Afternoon all

Can anyone help here please?

Have got a very early Discovery hot wire engine and EFI system and want to know if they ran a road speed transducer in the system? It is definitely hot wire and it is a 3.5 not 3.9 as the early ones were.

Just needing some clarification as putting a hot wire system onto a 4.2 in a 90 Land Rover and want to know if I still need to connect the road speed transducer.

I do have the bits to connect it and a complete 3.9 hot wire system as well - intending to chop both wiring looms up to make a wiring loom that will be long enough to put the ECU behind the seats, just need to know whether I need to bother with the road speed transducer?

Thanks

jwriyadh · Post by **jwriyadh** » Sun Apr 06, 2008 7:10 pm

AFIK all hotwire systems used a road speed transducer. Since it is used to guide the ECU software as to when it should manage the idle speed( aside from other uses) there would have been a different version of the software specifically for 3.5 hotwire system.

If you are using a 3.5 or 3.9 hotwire system to manage a 4.2 you would benefit from changing the tune resistor to a blue one. This assumes you are using lambda sensors, irrespective of whether you fit cats or not.

jw

landrovernuts · Post by **landrovernuts** » Sun Apr 06, 2008 7:52 pm

Thanks for the reply. In answer for your suggestions, I am using a white tune resister which is correct for the non cat 14 CUX system I ran before. The ECU has been set up to run this engine on a rolling road by Mark Adams when it was in a former vehicle (Range Rover)and after he worked his magic a nice 282 BHP was at the flywheel.

The reason for the change is the engine is now in a 90 landrover and I fitted a carb for simplicity, which has been a total disaster and now want my power and economy back.

It just happened that amoungst my spare bits and peices I had a complete 3.5 engine and hot wire injection out of a discovery, but there seems to be no road speed transducer, wire etc which made me wander if the very early ones did not have it fitted and would make the installation in the 90 easier.