MGRV8 won't start

[GeraldM]

Can anyone help, my RV8 won't start with the key, when l turn ignition on everything lights up & fuel pump works, but when I turnkey it goes dead. Car will start if I bump start it & everything works normally, but if l turn the key it cuts out again. If l disconnect the battery, then reconnect the lights come on again but goes dead again if l turn the key. It's a new battery & l took the starter off to test & it workd ok.

[t400ble]

Check earth leads?

[GeraldM]

Yes not done that yet

[TooMany2cvs]

GeraldM said:

Can anyone help, my RV8 won't start with the key, when l turn ignition on everything lights up & fuel pump works, but when I turnkey it goes dead. Car will start if I bump start it & everything works normally, but if l turn the key it cuts out again.

That sounds like ignition switch.

[GeraldM]

I thought it might be the switch, but that seems ok, l was wondering if the immobiliser is playing up.

[GeraldM]

I'll have a proper look at the weekend, thanks everybody.

[paintman]

Fully charge the battery with a battery charger just to be sure - appreciate you say it's a new battery, but never assume it's fully charged & are you sure you haven't been sold a duff one?

Connect a jump lead from the battery's earth terminal to a clean metal point on the engine & try starting again.

[GeraldM]

I've tried with 2 different batteries, both the same, it must be the earth to the engine, can't do anything til weekend, I'll keep everyone posted, thanks.

[george123]

I'd also say earth strap....had similar sounding issue on my Spider

[Norfolkandchance]

Are the battery terminals on tight? Can make a surprising difference.

[LuS1fer]

And is it the right battery. Something like 550CCA for a V8.

[v8250]

Gerald, I'm trying to remember if there are 1x or 2x earthing straps on the RV8. If only 1x it's always worth fitting a second. The std B's main earth strap is from the gearbox/mounting to body which often needs checking if heavy starting experienced. So, you could install an additional from rear of engine to body. It's also worth making sure there's some good distance between the two straps for good body current flow.

[GeraldM]

I don't know, l think I'll have to check every connection, can't do it this weekend now, I've booked a short break to Portugal, it'll have to be when l get back. On checking the wiring diagram, the car is fiited with 2 immobilsers, one in the boot & one behind the dash, l think the one behind the dash controls the starting, so it might be that one.