That wire he's talking about is the feed to the coil, although it may come out in the same area as the AFM bundle it is not related, this is the ignition trigger, and should go through a 6K8resistor. Without this the engine won't run at all.
Re: Rover 3.9 14CUX Hotwire - Fires Up but Won’t Run
Posted: Mon Nov 17, 2025 8:38 pm
by Ian Anderson
As I said about 20 years ago!
I was fairly sure it was black……but mind played tricks.
When that wire came disconnected my car would start but not run.
Ian
Re: Rover 3.9 14CUX Hotwire - Fires Up but Won’t Run
Posted: Mon Nov 17, 2025 8:49 pm
by Steve R
Definitely a whiff of Partridge about that video!
Good to see it all laid out though. Thanks for sharing, really useful. Yep, can see now that it’s the signal wire from coil to ecu and it does come out close to the MAF connector. All connected on mine.
Having done some more research I do suspect my fuel pressure could be low. Previous owner had installed a single external pump setup - I replaced the pump for a new one (so in my head had ruled this out), but sounds like it’s a big ask for one pump to lift fuel out of the tank and supply it at Efi pressures. Will test it properly at the weekend, but I feel a swirl pot and 2 pump setup might be next…
Re: Rover 3.9 14CUX Hotwire - Fires Up but Won’t Run
Posted: Mon Nov 17, 2025 9:57 pm
by GDCobra
Ian Anderson wrote: ↑Mon Nov 17, 2025 8:38 pm
As I said about 20 years ago!
I was fairly sure it was black……but mind played tricks.
When that wire came disconnected my car would start but not run.
Ian
That's surprising, with no pulse from the coil there is nothing to trigger an injection cycle (calculation and injector trigger) so should not run at all.
Only thing I can imagine is there was some fuel in the plenum or intake manifold (leaky injector maybe) so the engine would fire but then stop when all available fuel fumes burnt, a bit like starting a car with an alternate fuel source as a test for fuel or spark issues on crank no start.
Definitely a whiff of Partridge about that video!