The V8 Owners Forum -

checking out ecu wiring on my 3.9 hot wire . rebuilt engine over fueling. all plugs black. found idle valve not working and replaced replaced. ignition wire to ecu with resistor is giving 7.2 ohms is this within tolerance.
engine starts fine and runs but lacks power when gven some boot .

Hi Hotwire goes into fault mode for a get you home thing.
Basically it goes slobbery rich so as not to damage thisngs with too lean engine

But it's easy to reset

Disconnect the battery for 30 seconds - and reconnect it - no more error codes in it's memory!

Hell I even have a battery isolation switch fitted in case mine goes into this mode! saves getting the spanners out

Ian

The extra resistance is probably the resistance of the wire to the resistor.

dusty wrote: ignition wire to ecu with resistor is giving 7.2 ohms is this within tolerance.

Hello Dusty, could it be the resistor with WB wires indicated on this diagram, or a similar ignition set-up?



In which case its design value is 6,800 ohms and your 7,200 ohms (?) with 400 ohms difference is well within the normal 10% tolerance for these type of components. Its even close to 5% which is also another typical benchmark in electronic design tolerance. So no worries!

To be sure we are on the same wavelength verify you are not misreading the 'range' of your multimeter when measuring.

missed the "k", as wire resistance is usually under an ohm it's irrelevant here! Sorry for the mislead!

thanks for the replys. thats ok on the resistor . I have been disconecting the battery every time to clear ecu . engine also has a new cts and fuel regulator. tps checked out on ohms. do you think a different ecu will be worth a try

PM me your e-mail address if you want the Land Rover Hotwire ECU test manual.