Okay, ran a short earth lead between starter relay terminal 85 before it joins the RFD2 diode direct to bulkhead earthing point. with relay plugged back in had high expectations for car to start but when turned key to start position 3 in ignition - no crank - just clicking from the starter relay. I did then measure the voltage at terminal 30 to the starter motor with the relay plugged in and there was 12.8 volts present when relay was energised at the ignition key position 3.
So I'm now thinking that either the starter pinion is jammed with the flywheel ring gear after testing its function using a wire direct from the +ve battery terminal to terminal 30 and the engine turned over very well but without actually starting the engine as I wasn't using the ignition switch to energise it - (therefore I guess the other required electronic functions from the main ecu, fuel injectors etc would not be energised) and with no actual engine start to release the starter pinion drive again. OR I have a bad connection in the wiring somewhere south of terminal 30.
Next step is to get a spanner on the crankshaft pulley and rock the crank back and forth to see if that will disengage the starter pinion (if it indeed is that) and try again.
I'm fortunate that all this has happened with the car up on a two post ramp so I can at least get under it with ease - thank heavens for small mercies!
Let me know if you think I'm missing anything here or whether I ought to be checking something else that I haven't mentioned. Cheers, Ian

 

Never turn the crank backwards! i would put the 12v direct to the starter again to free it off, then retry your hotwired system.

 

I have tried putting 12v direct into the starter but that isn't doing anything?

 

OK, try turning the engine forwards only. That is clockwise as you look at the front of the engine.

 

Yeah, I don't intend forcing anything by trying to turn the engine by hand - I can only get tiny clockwise movements anyway due to the air con compressor pipes being in the way.
I removed the exhaust heat shield to get a better look at the starter and I tested for continuity of the wire from 87 on the relay plug to the solenoid and it would appear to be fine and connections to the starter motor (which appears to look relatively new) seem to be tight.
There is a 0.25" male spade connector from the solenoid that isn't attached to anything but I don't see any loose wire or anything in the area that it would be connected to. I'll try and upload a photo.

 

 

Okay, Success! Car starts and runs ! This following on from replacement of abs valve block, new front brake calipers and full bleeding of the system. My Abs warning light is still on though - took car for a short 3 mile drive, brakes seem to be working great, no spongy pedal or anything like that. Wheels lock up when braking hard (obviously no abs present when warning light on) I even swapped over the abs ECU unit in the boot with one I know is good and the light stays on. My brain is a bit fried thinking about all this! Anything I can check to see why the warning light is staying on?

 

Sorry If i misunderstood but didn't you say a few posts ago that you put 12V directly or to the wire that goes to the starter and you said you were able to spin the starter?:You are now saying that putting 12v directly to the starter, you get nothing?

 

When I spun the starter motor initially without the starter relay in place by linking a wire from terminal 30 direct to the +ve battery terminal, the starter motor engaged and turned the engine over nicely but it didn't start the engine as I wasn't turning it over through the ignition switch and therefore there was no power to the other electronic modules required to fire it up. I can't be 100% sure - but I think the issue with doing this was it left the starter pinion partially jammed in the flywheel ring gear. Someone who understands the starter operation better than myself might explain it better, but I think if there was a bit of wear on either the starter pinion or the flywheel ring gear then the starter pinion could get partially jammed particularly if the engine doesn't start and "throw" the pinion back as the flywheel speed picks up. When I tried the same thing again, I just got clicking from the starter solenoid due to it being partially jammed and not making internal electrical contact within the motor itself. That's when I got a socket on the crankshaft pulley to just turn the engine a fraction enough to hear the pinion return with a clunk. I then followed your advice and took a new earth direct from 85 to ground and this time (with the starter pinion now fully disengaged from the ring gear) I used the key to start the car and it worked! I have switched off and restarted the car several times and it seems ok (apart from the ABS warning light still on - but that is yet another thing to resolve ) It may be the case that I could occasionally have the starter jam on in the future - especially if battery power is low - I need to be mindful over this as the old trick of rocking a car whilst in gear to release the pinion would not work for an auto , I don't think...

 

Glad you got it sorted out, albeit I'm thinking you're still not quite sure what the original problem was. Unless the pinion gear was in such a position that created a jam with the flywheel, even with the pinion gear engaged and not pulled back after a successful start, the starter motor (healthy) should still have been able to spin the engine over engaged. Anyway, you did all the right things to make sure the start logic circuit was working and had power and ground where it should. Even with the control circuit working, the speed of the starter motor will depend on the main power cable connections, grounds, good battery,etc.

 

The car has been starting fine with the temporary ground wire in place bypassing the RFD2 diode, start inhibit switch and security module. I will be following up where the earthing problem lies soon - but I'm thinking the start inhibit switch could be the most likely contender - but i will work backwards from the security module first.
Thinking over why the starter wouldn't spin when jammed with the flywheel ring gear - I'm not 100% sure, but if the pinion had partially retracted but was still engaged with the ring gear - couldn't the solenoid have pulled the internal +ve contact within the starter motor itself open therefore not permitting current to flow to the motor? -- just a thought, but as I say it seems ok for now.

 

I think with the pinion partially or fully engaged, it will take a bit more energy to spin the motor. But no, even partially engaged, the electric part of the motor doesn't know where the pinion is, so when the solenoid is activated, it just spins the motor whatever position the pinion is in. It's the act of the engine/flywheel spinning faster than the pinion gear that retracts it once the engine starts. I believe there is a spring in there that assists the pinion gear to retract. Maybe that is weak.