Just run a cable direct from a bolt on the engine to the battery and see if it starts any better.


The factory earth should be very obvious. I think my factory one ran from the battery to just below the battery tray on the body then across to the intake manifold. (td42)

 

I've seen that particular one, mine run from the battery to chassis to the side off the Timing Cover.

 

Should also run one from engine to body/chassis, pretty sure there is a thread on here about this. If that can’t be found check out @geeyoutoo build thread, it’s in his signature panel, I know he has the extra earth strap.

 

yea that’s a great idea, I’m about to install one right now.

 

The main earth runs from the negative battery post to the engine block. It also connects to the body just under the battery.

The ECU earths for the RD28 are located (I think) on the front right hand side of the engine. These are a smaller gauge wire and there will be two or three of them.

Is the vehicle cranking over on the starter motor?

 

Correct, Mine runs from the negative terminal to Chassis, then on the side off the motor (Near timing Cover top left)


The issue I'm having is it won't crank at all with the key. I can hear what I think is a relay but won't crank over. How ever from the starter motor if I trip it with using a screw driver and hitting postive and negative terminal it starts..

 

Just Tried it on two different spots on the block and had no change unfortunately

 

Is the cranking on a GU rd28 controlled by the key? Or does the key only send a signal to the ECU, and the ECU decides whether or not to crank?

 

Directly via the key. Unless there is an aftermarket alarm fitted.

ECU doesn't control the starter motor.

 

Beside the fuse box under the bonnet (between fuse box and firewall side) there is a row of connectors. One of the ones near the engine should be a blue connector. Is this plugged together? Any corrosion?

 

If when tripping the starter motor you are shorting the two large terminals together it could still be a faulty starter motor. Is this the original starter motor?

Try giving the starter motor a couple of light hits with a hammer.