Can anyone help? ‘04 facelift MG ZT T 2.5l KV6 Non Start.

[COLVERT]

[Timefortea23]

Originally Posted by SD1too

Good work Dan!
Can you find this splice? The first place I'd look is behind the passenger footwell fusebox. The four output wires go to passenger fusebox connector C0581 pins 15, 33, 50 & 51.

Simon

Hi Simon. My dad and I had a good go at the car today. We've found the spliced Brown & Black wire as below photo:



We did not read 12v on any of this. After further investigation we found the below damaged wiring above the nearside wheel arch liner.



It appears to have worn away against the plastic liner. The brown and black had fully broken in half. We've now completed a solder repair to this cable and a couple of others that had been partially damaged. Once this repair was completed the car did start for 20 seconds. Initially it ran well but then it started to misfire.

We then put the wheel arch liner back in and dropped the car back to the ground. However now it won't start again and we're still not getting fuel to the engine bay. Since the repair though we are now getting 12V to the right side of the passenger footwell fuse board. After removal of the fuel pump relay, we're getting 12v to one of the control terminals but not 12v to either of the load terminals. We've also checked the relay's functionality with the battery and this seems to be operating correctly. Ditto double checked the inertial switch which seems to be working fine, we're getting 12v on either cable when back probing.

On review of the wiring diagram it looks like the control side of the fuel pump relay is covered by the ECU. Another note is that we plugged TOAF in to see if there where any codes that would highlight anything but nothing obvious. There was some codes about the VIS but I assume this wouldn't cause the lack of fuel signal? I tried to clear the codes but the problem persists.

As ever any further guidance would be greatly appreciated!

[Timefortea23]

Originally Posted by Atlan

Remove the u/b fusebox and backprobe connector C0571 for 12v on the outside brown/black wire. If none pull plug and check to see the pin hasn't snapped off.

Hi Atlan,

We had a go at this and we got 12v here. Thanks for the suggestion.

Cheers, Dan.

[Timefortea23]

Originally Posted by Greeners

If its not the fuse as it was in mine, Id plump for the inertia switch (as already suggested) possibly a wet side impact sensor, or damaged wiring between the UB fuse box and the interior

Hi David,

Thanks for the post. We definitely had damaged wiring as my reply recent reply on the thread. That's now resolved but still not starting. The Inertia switch and fuse are fine. I'll have a look into the side impact sensor but everything appears dry.

Cheers, Dan.

[Timefortea23]

Originally Posted by Thunderbolt

Mum found the spare key, no change, it is the same so I think it isn’t the immobiliser.
Fuel pump kicks in when you turn the key for a couple of seconds.

Hope you get it sorted Calum. Cheers, Dan.

[SD1too]

Hi Ivan,

Excellent diagnostic work, well done!

Originally Posted by Timefortea23

We've found the spliced Brown & Black wire as below photo ...

That blue insulating tape doesn't look like the work of the factory to me or if it is, someone has been in there.

If you're getting 12v on both sides of the inertia switch but not to the fuel pump relay contacts (load terminals) then that points to another splice. This is in the brown/light green wire from the inertia switch. It contains three wires of that colour code. Can you find that?

VIS fault codes won't affect starting the engine.

Simon

[Thunderbolt]

Originally Posted by Timefortea23

Hope you get it sorted Calum. Cheers, Dan.

You too Dan.

[Greeners]

Light blue insulating tape is the work of the factory. The crimp and tape approach is found throughout the loom.

As you've found some damage, I would pop the wing off and strip the covering off the loom and check each wire its entire length for damage or breaks.

The fact it started after you repaired that damage would indicate that part of the loom is suspect.

Also take the UBFB out and check for damage on the connectors underneath

[Timefortea23]

Originally Posted by SD1too

If you're getting 12v on both sides of the inertia switch but not to the fuel pump relay contacts (load terminals) then that points to another splice. This is in the brown/light green wire from the inertia switch. It contains three wires of that colour code. Can you find that?

Hi Simon.

So after some further work yesterday, we found that the inertia switch wasn't conducting reliably so this was bi-passed and provided a reliable 12 volts to the pump relay and the pump is now working when the ignition is turned on so we have fuel as well as sparks.

Unfortunately we still have an engine that won’t start and an engine warning light on The Dash, TOAF seems to report there are problems with coil packs 1,2,3 & 4 yet they are sparking.

Further work undertaken today was remove all the sparking plugs. The are pretty black, indicating running rich & have a gap of approx 1.3 mm. Wire brushed & gapped to 0.8 mm we spun the engine without plugs to expel any excess fuel. Re assemble still no good !

Checked the Crank Position Sensor with a multi-meter got following readings to earth from back of plug:-
Yellow / Green 12.5 volts;
White / Blue 5 volts (dc) static to 2.2 volts (dc) & 175 Hz cranked .
Black 0.002 volts
And same tests on The Cam Position Sensor
Yellow / Green 12.75 volts;(static) dropping to 10.8 Volts cranking.
Blue 0.032 volts (dc) static 1.3 Hz cranked .
Black 0.0024 volts

Is it possible that the fuel injectors are not working ? Is it possible that a broken wire that we missed when repairing the harness is causing the issues.
Would it be beneficial to try another ECU/Immobiliser/Key? TOAF scans below:



Cheers,

Dan.

[Timefortea23]

Originally Posted by Greeners

As you've found some damage, I would pop the wing off and strip the covering off the loom and check each wire its entire length for damage or breaks.

The fact it started after you repaired that damage would indicate that part of the loom is suspect.

Hi David,

We'll have a deeper look next weekend. As my post a few minutes ago we've found that the inertia switch wasn't being reliable so we've bypassed it but still the engine isn't starting.

Originally Posted by Greeners

Also take the UBFB out and check for damage on the connectors underneath

I've had a good look here and the connectors seem OK.

Cheers,

Dan.