Dash on , but car wont start.

The Oily Bits S2 Specific Topics
1

Got a funny intermittent one here.

This tends to be after I have unplugged from the trickle charger.

The car just wont start.

The dash comes on , but the extra twist of the key does nothing. The immo is off ( light not illuminated on the dash ) and can lock, unlock car as normal. Everything else works. Fans the lot. I can hear the fuel pump prime.

Sometimes removing the +ive from the battery sorts it out, other times no matter how many twists of the key it wont start.

This morning tried it , nothing. Left it a bit, made a brew and then wham. Started.

Can now start the car on demand.

Any suggestions?

2

I THINK the immobiliser cuts two circuits, it did on my S1. The fuel pump and maybe the ecu. If only the fuel pump is enabled it will crank, the dash will light but it will not start. Given how often the immobiliser fail I’d start there.

…is a, guessing madly, SELOC style…

3

:smiley:

It doesnt even crank.

Literally the dash is illuminated but no one is home.

I have noticed that it only tends to do it when I have immediately removed my trickle charger. It started straight away after this morning episode when I left it sulking in the garage without the charger on. .

4

I’m sure that is what happens if you don’t turn off the immobiliser?

5

I press the button on the fob and the light , lights up.

Press it again on it goes off?

6

wonder if you can easily bypass the immobiliser on the S2 like you can on an S1?

7

Not sure.

This one doesn’t specifically list the exige s2 but does the s2 Elise with 2zz…

8

If yours has either Cobra or Meta the Eliseparts unit will do as intended.

Might also be worth checking the fob battery although I doubt it is that since it appears to work fine on all other occasions.

From they symptoms you described originally it sounds rather like a residual voltage after the charger is removed. If that’s the case it might be that the immobiliser isn’t unlatching immediately (can’t speak for the Cobra but the Meta has two internal relays). If you haven’t already, try the following:

a) Connect the charger and leave it on for a while
b) Switch the charger off, leaving it connected to the battery for a few minutes, the detach it
c) Try to start the car in the normal procedure

9

My thoughts as well regarding residual charge.

I was going to alter the way I detached the charger. I was going to remove the charger while powered on rather than power off and then remove.

Ill take your suggestion on board and see what happens.

Appreciate your input ( and Ade )

10

I would avoid detaching the charger before switching it off as this can cause electronic issues in itself.

11

Noted.

Will follow your recommended advice

12

Do report back :slight_smile:

We see a lot of chargers (my company works on portable lab equipment) where the output voltage take a long time to die-off after they’ve been switched off from the mains. This isn’t a fault, but I’m wondering if leaving your powered-down charger connected for a while might allow any residual to decay.

Thinking out loud on that one, I wonder if there is a fail-safe somewhere that is designed to prevent starting the car whilst a charger is attached? That would make sense in a way, so as not to overload the charger with a massive current draw. If there’s a residual voltage it may be keeping that ‘live’, hence the car won’t start just after disconnecting the charger.

But as I say, that’s just ‘thinking out loud’…

13

Ill get to try the theory tomorrow morning.

Ill head out of the house 20 minutes earlier than normal and power off at the wall , leave connected and return to it 10 minutes before I need to set off, and hopefully it will start. From memory it tends to be find on a Wednesday ( after I last use it on a Monday and put it on trickle ) but fails on a Monday morning after typically last using it on a Saturday , or even Wednesday evening.

14

Ah, so it doesn’t like Mondays…is there a Mr Geldof in the previous owners list?

15

:grin:

16

Turned trickle charger off at 0810. Attempted a start at 0820

Fired first time

Car will be on charge again this evening until possibly Saturday or even Monday. Will review.

17

Result? Luck? Wednesday effect? :confused:

18

Strange one isnt it ?

19

Odd…but then it is a Lotus! Let’s see what happens with another few repeats of same, with different days :crazy:

20

I doubt it’s anything to do with the charger., it can only deliver an amp or so and battery produces over 100 to crank the car. The lighter socket is always live so the charger will be held at the voltage of the battery which will win the voltage fight.

Let’s see, hopefully you have a fix but I don’t understand it.