The V8 Owners Forum -

Evening all
I have a 14CUX ECU on my 3.9 Rover V8. I’ve had to do a little rewiring and have come a cropper.
I have a yellow wire leading to the ECU plug which I have traced to be pin 6 (Speed transducer). After doing some research I’ve worked out this is a variable voltage pulse signal to the ECU. My vehicle does not have or require any sort of speed sensor so I wondered what the importance of this signal was and if it can in any way be replicated.



Appreciate your time
Tom

I would try it without it just allows the idle speed to wind down progressively as you approach junctions etc and was incorporated for the top speed limiter when fitted to certain LR 4WD vehicles, some vehicles will run happy without this speedo pulse I have a TVR that had no speed signal from the pick-up on the rear axle for 2 summers (I used the satnav speedo) on an RV8, even when I decided to renew the pick-up unit it made no notable difference to the cars behavior, however you need to make sure the base idle bleed screw settings are correct or you may be plagued by stalling while you approach junctions etc

Thanks for the reply. The vehicle is never likely to see a junction, only a Welsh logging track! The 6 pin connector was previously wired to an ignition 12volt but clearly this was not correct. The engine has never stalled but does have an unsettled high idle (revs will sit at 1500rpm but roughly every minute drop to 800rpm for a few seconds).

It is used for two purposes.

1.) To detect when vehicle is moving so that it can disconnect the idle speed control mode (when car moves).

2.) To drive the electronic speedometer.

All as per the LR manual I have.

Is that the pin that needs a 490 hom resistor across it to fool the ECU into ignoring the expected tach signal?

Ian

Ian Anderson wrote:Is that the pin that needs a 490 hom resistor across it to fool the ECU into ignoring the expected tach signal?

Ian

No Ian thats another