Non starting Caterham Supersport

[Andy Bell]

I was having some brake issues and found it was caused by the high effort brake pedal being way too high effort (or my legs were too weedy) so today I changed the pedal to the normal one. Unfortunately in doing this I appear to have caused the car to be unable to start completely!

I visually checked all the fuses and I am completely stumped what I could have done. Given I was only working in the brake/clutch/accelerator housing i was nowhere near electrics.

What happens is in this video http://www.youtube.com/watch?v=qG4NxBqHJ-M. Anyone ever heard of this bizarreness before - my only thinking is i forgot to hit the master switch and perhaps something metal hit something else *guess*

[Helluvaname]

Try pressing in the top of the inertia switch

[7ss]

Do you have an FIA switch mounted on the scuttle? Could have knocked some of the wiring whilst working on the pedals?

[Andy Bell]

so Just had the very helpful DCL over for a good few hours and what was found was:

Definitely not fuses
Inertia switch seems to have been removed as part of the academy options (car was academy -> tracksport -> supersport) - wires appear to be soldered/taped together
Checked wiring in FIA switch all seemed well and was behind the knee protector
Easy map was plugged in and whilst it can detect there is an ECU plugged it cannot seem to fetch anything from it
Sounds like fuel pump isnt starting either
Battery was low (12.5v) so going to get a battery conditioner on it

puzzled

Edited by Andy Bell on Sunday 14th July 15:31

[DCL]

Yep, puzzling! As Andy says, fuses, relays, and immobiliser seem to be working fine. Easymap intermittently recognise the ECU but doesn't give any sensible data. The temperature gauge is stuck at max - is that normal on the sigma when the engine is not running? Fuel pump seems not to be priming - is this controlled by the ECU or it powered all the time?

My thoughts at the moment are that there is a wiring fault somewhere that is preventing the ECU from powering up properly. Andy, I don't think it is the ECU at fault, but it may be that the next step is to send the ECU to be tested and eliminate it from the equation. A bit easier that sending the car somewhere at this stage.

Edit to add: the VVbox shows no TPS voltage which confirms ECU is most likely not powered.

Edited by DCL on Sunday 14th July 16:35

[Andy Bell]

Only other thing i did (but i was out in car between then and it braking) was jack it up. Will have to check if pinched a wire.

nope not that and as people can tell I am starting to write down everything that occurred - i coughed loudly..

Edited by Andy Bell on Sunday 14th July 17:25

[Blue in Lincoln]

Andy

One post says yours is a sigma engine if so check the wiring to the rev counter. I had a similar issue and the rev counter wasn't getting power so the engine wouldn't start.

Cheers
Paul

[DCL]

Done a bit of trawling through the wiring diagram and the fuel pump is controlled by the ECU. The ECU has two power supplies, one permanent and the other from the ignition circuit. Easimap suggest the permanent supply is there but it is not turning on with the ignition circuit. We know the ignition circuit that powers the ECU is working as the starter button uses this, and it works. That leaves one joint and two plugs between what we know is good and the ECU.

Getting there Andy!

[DCL]

Blue in Lincoln said:

Andy

One post says yours is a sigma engine if so check the wiring to the rev counter. I had a similar issue and the rev counter wasn't getting power so the engine wouldn't start.

Cheers
Paul

Interesting! Now that is an area that may have been disturbed by the brake pedal change - we noticed that the Aces unit was powering up with the FIA switch.

Andy, try unplugging the two leads in the Aces unit under the dash and see if it starts!

[Andy Bell]

unplugged the two cables into aces and unfortunately same result.

[rubystone]

Are you 100% sure you haven't blown the ECU fuse? It is usually rated at 25amps but that is always a bit marginal...common mod is to upgrade it to 30amp. Pull it out and check it carefully/swap it with another.

[Andy Bell]

rubystone said:

Are you 100% sure you haven't blown the ECU fuse?

Hmm i checked manual and there isnt a fuse rated at 25amp or one marked ecu fuse? Checked both assembly guide and handbook and none the wiser. On the duratec I did see 'N Battery supply engine 30A'. IN saying that I did change all the fuses that were engine related but they were all 15a.

interesting thread http://www.pistonheads.com/gassing/topic.asp?h=0&a...

also chasing down suggestions on blatchat http://www.blatchat.com/t.asp?id=172255

Hello,

This is a long shot but I had exactly the same symptoms in my 2008 Roadsport last year. In my case it turned out to be the speed sensor on the off-side rear wheel which had shorted where the wire enters the sensor. The wires get a lot of flex as the wheel moves and so I guess are vulnerable. Worth a look, there's a plug connection on the chassis wide you can undo. I fitted the new one with a lot of precautions against a recurrence.

Rob

Which is interesting as I had car up on axle stand. Also found lots of similar posts of not hearing fuel pump prime:
http://www.blatchat.com/t.asp?id=217148 (ulp ecu)
http://www.blatchat.com/t.asp?id=212555

Just seems to be endless what if's!

Edited by Andy Bell on Monday 15th July 14:34

[DCL]

Speed sensor is a possibility as it is on the ignition circuit. The ECU fuses are first and second 15amp ones. The second is the switched supply.

[Andy Bell]

I am so fuc**** embarrassed - I really am. I am not kidding that my face is actually red at the moment and I feel shame :[

So I was reading on blatchat that even with 7l of fuel odd in tank the car can fail to start. I had put 5l in car after last use so (stupidly) assumed that would be enough.... I guess I must have had a nearly empty tank before I put more in... guess where this is going...

Just in case I decided to put 10l more in and guess what - it started. I can only think that perhaps jacking car up at front and then at back took fuel away from the key areas and at the moment its sitting on a slight slope.

DCL - please let me know if you want to come round and beat me up. Only plus side I can re-cable tie things properly and get punched a few times for my troubles.

Edited by Andy Bell on Monday 15th July 15:05

[CharlesElliott]

Glad you sorted it.

For future reference - the rear wheel speed sensor is on the fuel pump circuit (guess it was a handy wire to tap into) and so if the sensor shorts or the wiring is damaged, it blows the fuel pump circuit.

Edited by CharlesElliott on Monday 15th July 15:24

[DCL]

Glad you got it started Andy! If it was only fuel them I feel a bit stupid too!! To be honest, I think charging the battery may have more to do with it. Can't believe no fuel would stop the ECU powering up or the pump trying to prime.

[Andy Bell]

yes to be fair it wasn't like just put fuel in. Topped up battery fluid (which was low), put a charge in it and fuel but still. Is allowing me to clean up some overly tight cable ties that David pointed out and remove the 4.2kg lead ballast that was in the passenger side...

Trying to figure out what this is as well - the mysterious blue 'thing' which is beside what looks like a fuel pressure device:

Edited by Andy Bell on Monday 15th July 17:36

[tom0507]

Andy Bell said:

yes to be fair it wasn't like just put fuel in. Topped up battery fluid (which was low), put a charge in it and fuel but still. Is allowing me to clean up some overly tight cable ties that David pointed out and remove the 4.2kg lead ballast that was in the passenger side...

Trying to figure out what this is as well - the mysterious blue 'thing' which is beside what looks like a fuel pressure device:

Edited by Andy Bell on Monday 15th July 17:36

The 'blue thing' is part of the fire extinguisher system. One points at the fuel rail, another in the drivers footwell and another pointing at the fuel tank.
The 'fuel pressure device' is a MSA fuel sample union used when the scrutineers want to take a sample of fuel after a race.

[Andy Bell]

Awesome cheers!

[Andy Bell]

So plot thickens - at least for me. As had been previously said I had a non-starting car which puzzled me (didn't take much) and unfortunately DCL too. I put in some fuel and it fixed it - leaving me feeling a proper wally for it being something so simple. But here is where my confusion is:

When the car wouldn't start I had a 10 litre can that had maybe 2-3 litres used. When I put the whole lot on the car started <- at this point I felt rather silly.

I just drove for about 1 mile to check brakes (which are so much better changing to standard pedal) and then to petrol station in preparation for track day on Saturday. I was expecting to get a decent amount of fuel in but only managed about 6.5 litres.

Given its a 36 litre tank that means that I had 36-7-6.5=22.5 litres in the car when it would not start.

As DCL said I hooked it up to a batter conditioner (ctek MXS 5.0) to charge it as well as lots of cables being unplugged/plugged in. Still perplexed though.