Dead 2011 Academy Car

[Benjam]

My 2011 academy car (125 Sigma) died yesterday after a few hours on track at Thruxton, spluttering through Church (flat out 4th gear righthander) before briefly recovering and then pertinently stopping a few hundred yards down the road.

She turns over but doesn't appear to have any fuel pressure and can't hear the pump priming when switching the ignition on any more. Checked the obvious things (fuse, relay, inertia switch, etc) as well trying to measure a voltage across the pump but couldn't find one which indicates something wiring related but I heard the pumps are prone to failure.

My initial plan was to hard-wire the pump with a 12v feed to see if it runs and rule out pump failure as the cause but I'm not sure which of the 4 pins to use?

Any other things to try please?

Thanks
Ben

[HustleRussell]

Does the car have a fuel cut-off switch (inertia type)?
In terms of shorting the pump relay, once you have located the right one it'll be quite simple to short the terminals together with a length of wire with a male 6.3mm spade connector at each end. The relays usually have a handy diagram etched on the side from which you can deduce which is the permanent live and switched live.

[Benjam]

It does have a inertia switch but I shorted the terminals together to rule out failure of this part. I also tried a replacement relay for the fuel pump but not shorting this all together. My plan was to physically connect the pump to 12v to verify it was operating. B

[tom0507]

I'd take the fuel pump out of the tank and have a look at it. The pump just hangs in the tank, vibration and g-force can shake them to pieces and cause them to fail. We've had a few go, but now we've got a small modification, we've not had any failures.

[downsman]

tom0507 said:

I'd take the fuel pump out of the tank and have a look at it. The pump just hangs in the tank, vibration and g-force can shake them to pieces and cause them to fail. We've had a few go, but now we've got a small modification, we've not had any failures.

Any chance you could tell us what the modification is?
The pumps are pretty expensive, so I'd be keen to try and stop it failing on my sigma car

[RacerMike]

Does the fuel gauge still work? If it's playing up, it's more than likely to be the pump/pickup which just hangs unsupported in the tank. You can sort of fix, by sticking a rivet through the plastic part to the main body, but it's not really that long lasting.

[iguana]

No advice here I'm afraid, but I was on that day, think spotted you pulled over on right between church & chicane.

Flat in 4th tho? Even in my slow car That's brake from 120 & turn in at 110 for me, you can't be in 4th for that surely?

[Benjam]

@Mike... The gauge is fine.
@iguana... That was me and yes, no lift but with 125 mighty horses and van tyres that's only about 100

[iguana]

I ment surely you are in 5th there no?

Bit of footage from that day, larking with my pal in the Golf camera car- I'm in the e36 328 ahead

http://www.youtube.com/watch?v=T9AvixJipr0&hd=...

Edited by iguana on Saturday 29th June 01:04

[downsman]

My 125 Roadsport won't hit maximum revs in 4th even with the 3.92 diff. 5th is just for motorway cruising

[RacerMike]

You only start to use 5th properly once you get to Supersports. Even then, it's only the really long straights!

Not sure what to suggest then. I sounds like it must be the pump, but being such a costly part I'd be hesitant to replace straight away. You can check if it's broken relatively easily. Unscrew the boot floor to get to the tank and then unbolt the pump assembly and you can pull it out of the tank to inspect

[Benjam]

Yup, 5th just makes less noise than 4th but the speed remains the same!

Just stuck 12v directly to the pump and it whirrs away fine but when I unscrewed the top and tried to lift the pump out it appears to be in two separate sections with a coiled spring section holding the two parts together. Is that correct please?

Looks like its not in two parts when new but can't argue with the noise it makes when powered directly...

http://www.caterhamparts.co.uk/product.php?id_prod...

Also doesn't explain why the pump connector isn't seeing 12v to prime the pump when I turn the ignition on?

Even more confused now!

B

[Benjam]

Even more bizarre... Reconnected the pump and the bloody car started!

Suspect the pump isn't right internally but awaiting confirmation from those that know what it should look like please.

Also, any cheaper sources of the pump,as its over 300 quid from Caterham?

Cheers
Ben

[Grubbster]

My 2013 car started suffering with an intermittent misfire and has cut out once (at Brands, flat out), CC told me to give all the relays under the dash a push and this seemed to fix it. Part of my trackday routine is now to give all the relays a push before I go out - no idea why this worked though, none of them seemed to move at all but it has been OK since. I've checked for pushed back pins and dodgy earths but never found anything amiss.

[Benjam]

Hey guys. pretty sure the probelm is fuel pump related so any ideas of a cheaper source of standard pumps, ways to prevent a new pump from failing in the same way or an alternative pump solution please?

Thanks
Ben