Won't start (again... and again)

Intermittently over the last 18Months (Maybe half a dozen times) I have had a repeat of a problem that I had where I get no spark or fuel, engine cranks fine but will not start.

Originally the Immobiliser was replaced under warranty, but this did not cure the problem.

I have since suspected that the problem is more pronounced when starting up with the car parked on an incline, and in generally when low on fuel (e.g. Refi11) but far from empty. I have found I can clear this at times by rolling the car off the incline and attempting a restart again. I am almost certain that the tone from the fuel pump also changes. At time it wont start it goes through an initial pumping where the tone does not change it just whirs as if very lightly loaded. Moving the car to level ground and the fuel pump start up tone changes from brief initial whiring to a deaper note as if the fuel pump has picked up and is working harder.

Other time I have found that just keeping the engine cranking for 20Secs or so and the thing just suddenly bursts into life.

Does the ECU sense the fuel pressure and inhibit spark and injection if there is not enough pressure?

Lots of other things have been 90% + eliminated:

Inertia Cut-off
Crank Sensor

The problem is back with a vengeance now, one option would be to eliminate the most likely source of problem (Lotus ECU) and go for an Emerald. What do you think?


It could possibly be an intermittant blockage in the fuel pipe at the tank end. Russ had this problem after fitting a lightweight tank.

Good luck!


Perhaps I will blow down the pipe to see what that does. I have booked in at Emerald for the 11 Aug in any case, it was about time that the flaky Lotus unit was binned in any case.


I had a similar problem a while back. I’ll bet your problem isn’t the same, but I’ll share my experience anyway.
The fuse for the ECU was sort of half-blown. You could just see a break in the wire, but it was still touching. Sometimes the car would start, and sometimes it wouldn’t.

Emerald eh - ooh suits you sir - would you like it fitted sir - nice and tight sir - ooh yes sir!!!

The ECU doesn’t sense fuel pressure. However your description on the tone of the pump sounds like the system may not be holding pressure and the fuel is draining from the injector rail and pipes, this could be caused by something as simple as the fuel filler cap, does it hiss when you undo it?

Decided this needs a trophy as I think I know what it is

I had this problem also, and spent weeks (and some money with Bell and Colvill) trying to get it sorted - to no avail.

Eventually I found that a fellow sprinter (Simon Thornley) who hasa megaK in his Westfield told me hte secret.

Basically, the battery specced in the Exige is too small (bear with me on this - it’s going somewhere) - the Elise specs a 063 battery, which is itself smaller than MG recommend for the MGF - then the Exige has a higher compression ratio than the standard engine (11 rather than 10.5) - which means the battery should be even bigger, but isn’t.

Now, on the K series, there is a crank sensor - the wierd way that the ECU is written means that when the ignition is turned on, the ECU allows the cranking relay to operate, but not the relay which controls the injectors or coil pack. These are not switched on until the engine has got a satisfactory response from the crank sensor that the engine is turning over fast enough.

All seems OK so far - however, if the engine is slightly slow - which could be your battery just a tiddly bit under full charge, then the engine does not crank quick enough and the crank sensor throws a wobbly and refuses to tell the ECU to fire anything else up - hence the cranks OK but no spark or injectors.

Most people tend to let go of the key, leave it a bit and try again - here is the problem - the ECU does not reset until the ignition is fully off for at least 30 seconds - therefore just getting back in and trying again without the ignition having been turned off will not help.

Then you kick the car, go inside for a beer - go back to it the next day and it bloody starts, purely because the engine might be cranking just a little faster. Truth is, had you just turned off the ignition, left it for 2 mins and come back it may well have started anyway. Seems that Exiges are right on the threshold speed to crank - sometimes it just doesn’t get it going fast enough, and you can never tell when that will be.

Simon from MG confided in me that they have ECUs in Rover which are modified with a green LED and red LED that tell them visibly whether the engine is cranking over quick enough if they get a problem on the production line - that’s how common it is even with the correct battery.

With the standard battery, you will never fix this problem (assuming your Exige suffers - some have less volt drops in the electrics and will never be afflicted)

My fix has been to fit a bigger battery an 065 rather than an 063 - gives 520 amps of crank instead of 340. The only problem is that it is 1 inch bigger in the left to right dimension when looking down from above. It is possible to fit, but bloody difficult - basically you have to pull wiring as far out the way as possible, remove the radiator shorud and then remove the 5 bolts holding the heater in place and slide the heater as far to the left as possible. Then you can JUST squeeze the bigger battery through the gap by tilting it - once it’s in it has plenty of room as there is clearance on the floor under the chassis leg, so the heater can be put back into it’s normal position. The battery clamp has to have the right hand edge removed to make way for the wider battery, but once it’s in, it’s in and will not go anywhere. Since then, job done, no more starting problems, and a battery that sits for weeks longer before needing a charge

Sorry for the long post


Yes I do get a hiss when I remove the Cap, but think you could well be right with the problem being with the fuel supply. I put another 20lts of fuel in, and it started up fine, could also be consistent with Peskys suggestion about crap in the Tank, just filling up may have stired it up and moved any blockage.

The gauge now reads 30lts I put in 5lts when I first got the problem, and then the 20lts so the tank must have been down to 5lts when the problem first started.

I will just have to keep the tank well topped up for now (ohh the weight of all that fuel!!!). In a way I would like to get conclusive diagnosis, as this only happens every 2-3 months, so even if I get the tank drained and other possible causes sorted, I wont really be convinced the problem sorted unless I get a good 6months+ trouble free.

Mike - Maybe I should just get a stack of gauges, fuel pressure, Inlet Manifold Temp, Oil Pressure, ECU voltage, Oil Temp,Oil Pressure, gear selection indicator, Boost Guage (well oneday), I could leave enough space to just leave a peep hole out through the windscreen, but I would look a bit of a twat just like someone else I kn…oohhhh err mummble mumble… no gauges are good gauges are cool…now that would suit you sir!.. I bet you have plans for the yaw and roll gauges on your motor(way) boat.

Decided this needs a trophy as I think I know what it is

Oh no just when I convinced myself I was on the track of the cause… this could just fit the symptoms as well… I mentioned that sometimes if I kept the engine craanking for 20-30Sec that it would suddenly come to life…

The battery in my exiges is usually pretty well up to charge and seems to be able to keep cranking long enough for the oil pump to do its job and I have noticed the engine starts to turn over more freely and faster after a good 10-15 secs, then followed by it coming to life. Apart from puting 20lts of fuel in I also had the battery on charge as last nights attempt had pretty much drained it, so who knows.


Russ’s problem was not actually crap in the tank. The rubber feed pipe from the tank had degraded at the tank end, & was effectively “self sealing” to the extent that the petrol pump was intermittantly unable to pump fuel out of the tank. Strange but true

Mark’s “thesis” is also a very interesting read - hope my car doesn’t suffer from this problem - aircon car & battery space = help!!!

Damn forgot the inclinometer and the altitude guage - now wheres that DT catalogue and that 16 pod dash conversion - god theres never enough space in these bloody cars - now if I put the rev counter on the bonnet corvette style with the nos level guage and the tyre pressure read outs I could get the others in - but where to put the ripspeed map reading light and multipoint cigar lighter adapter for the fridge and the driver fan!!!


PS Don’t knock the Yatch - we’re all taking anti motion sickness tabs and we’ll be OK.
PPS need some old tyres (ao48’s) for putting on the side for parking after cruising - any spare???