My battery died yesterday evening, and had to have it jump started. It started twice after, both times it ran for a few seconds then cut out. Since that happened, now the car cranks but it does not start anymore. I’ve checked all fuses and they’re OK, there’s spark and fuel pump is turning on. Unfortunately don’t have a spare key to try starting it with that.
Am I right to think if it’s an immobiliser fault? It has the factory fitted immobiliser. If it is, what is there to do about it?
If there’s anyone around the Slough area that has time to come take a look at it, I’d be more than happy to pay for it.
Unfortunately the immobiliser emulator service is currently only available for the MK2.5 cars which fortunately is where all issue with these seems to be at the moment.
The problems with this car began after jump starting so regrettably my theory is an electrically spiked immobiliser.
Initially this caused incompatability symptoms with a stall after running perfectly for a very short while (< 1 second, first two attempts) and then cranking but no start.
The damage may have progressed although disconnecting the battery may allow the 1 second run again.
Unfortunately the only cure I am aware of is replacement of the immobiliser and associated parts from a similar working car.
I guess if it does turn out to be the immobiliser there’s nothing to lose by trying my suggestions (if you haven’t already tried them before) in the hope it (the car) gets the point and starts correctly for you.
You don’t actually mention if you got a new battery, or just charged the old one. If it’s still the old one I would try a different battery even if it’s borrowed from another vehicle.
I’ve also noticed with the cars I’ve had with immobilisers that often they’ll crank and not start if the earth terminal isn’t tightened up enough, in fact my old Golf was awful for just how tight the earth terminal had to be before the engine would start - less so on the MX5, but I have had it happen with an iffy battery.
I have not yet tried with a different battery, I’ll have to do that tomorrow morning, I’ve made sure the earth was very tight on my current battery but its worth a shot trying it with a different one before I go ahead and buy any other parts necessary.
From 1994 to cars produced up to say 1995 1996 an aftermarket system was fitted at the keyside when the cars arrived in the UK. It operated via a fob you touched to a receptor on the dash.
They had issues after a while and the system was removable.
These cars may well have still been for sale new to let’s say Dec 1995 or whenever.
Cars produced from around 1996 like the MK2 cars had a different ECU. That ecu was coded to a separate Immobiliser and a matching set of keys with Immobiliser transducers.
Wayne are you saying both versions of the car can have the immobiliser disabled.
Would be really interested to know how the factory immobiliser can be removed. As far as I know the only way around this is to use an ecu such as Megasquirt.
Early cars, typically 1989 - 1995 with dealer fitted immobilisers are a different matter - is this what you mean?