Won't start - occasionally, after retro fit new aero cap and filler hose parts.

[anthonym]

Won't start - occasionally. Year 2000 R500K. Immediately before this problem started I changed the aero filler cap, hose and closed off a (second) breather from the middle top of the tank. The symptoms are when hot or stone cold, engine turns over with gusto, but not the slightest attempt at firing. Release petrol cap (no audible "whoosh" sound), engine starts (possibly extended pump priming noise). Last time it did not start until I removed and reinserted the cut-out key (I guess resetting the ECU). Problem does not happen when engine is running, i.e. it does not stall. Also recently prior to this fitted the "breather mod" to the (first) breather hose. It has been suggested the (new) one way valve is requiring a little too much suction to open. It has been pointed out that last time when I got out and removed/reinserted the cut out key, my getting out of the car was involved (on this occasion the fuel cap was released by a bystander). I remain perplexed. 

and the new cap still leaks fuel on left handers, which is quite a conundrum since the other problem is the opposite of a leak.

I've asked CC and will advise what they suggest when they have had time to think. However, anyone else had this/these or similar problems?

See you at Donnington

Anthony

[Jonathan Kay]

Problem does not happen when engine is running, i.e. it does not stall.

That includes prolonged high power running... not just idle?

Jonathan

[SM25T]

Try removing the one way valve as we discussed .... or teeing the surplus breather into the small bore vent hose that leads downwards from the filler hose ... As they were both connected to the same place on the old filler neck ?

[SM25T]

Prolonged high power running ... oh yes ... having followed him all over the Alps a couple of weeks ago :-)

[Jonathan Kay]

:-)

I don't understand how restricted breathing would prevent starting but allow that...

Jonathan

[anthonym]

aye well, neither do we. I try not to ask easy questions :-)

forgot to chase CC today.. need a reminder tomorrow

Ian, yes wondering how to let in a Tee piece; or even simply adding another valve in to the blocked off breather, so if that works I have my answer. Stands to reason there should be a good reason why that second breather exists at all and that blocking it wasn't such a good idea. 

No they weren't connected to the same place on the old filler neck, in that they did vent in (out of) to the filler neck, but each had it's own separate connection.

 

[Wrightpayne]

I'm about to fit an aero cap to my K series car which has the two small breathers connecting to the neck, however, the new one only has 1 small breather. I was going to block off the one in the top of the tank as well. I dont really understand why it is there, as there is a 16mm pipe between tank and filler neck adjacent to the large fuel inlet? Surely this will give all the breathing needed?

This year I've removed the charcoal canister and fitted a non return valve and looped pipe to the other small tube on the filler neck. I now get a whoosh when I take the cap off but cannot work out if its pressure or vacuum. I'll have to pay more attention next time I fill up!

Ian

[SM25T]

Fitted my new aero cap yesterday. Had to tighten the 10mm nut a fair bit to get the cap to seal securely when clasp lever snapped shut. All seems ok.

[SM25T]

Anthony .... different spigots ... But connected to the same space ?

[anthonym]

edit after thinking: no, not in to the same space; that's what confused me. Number 1 (say) now has the "breathing mod" and breathes from the filler neck to the tarmac beneath, with a one way valve (and the required S bend). Number 2 previously breathed from the top centre of the tank into the filler neck space. So 2 was being fed air by 1. Both were not breathing from the same space, one was into the filler neck the other was out of the filler neck. 

 

yes... well... let me think, ok save me retyping our app chat:

just spoken with Lee in Service and Tony in Parts about the left cornering aero cap fuel leak and the non starting. Judging from Tony's reaction, which was that on track with a full tank he still expects some fuel loss and Lee saying they have seen starting issues of late with similar age (year 2000) cars due to the in tank filter (in addition to the external filter) being a bit suspect at that age. Neither Redline nor CC can supply a pump kit. Tony suggested Merlin Motorsport for "just the pump" part of the assembly, which I notice has a bag type filter included:

https://www.merlinmotorsport.co.uk/p/fuel-pump-for-caterham-7-motorsport-upgrade-pump-itp144

and you said: Tighten the 10mm nut on back of cap

Not done that yet, sounds promising.

so I have ordered one (pump)  for pre-1pm delivery here tomorrow (so before I depart to Donnington) . They (Merlin M) say 99% sure that will work. No one has mentioned the tightening bolt you mentioned so that's still No 1 possibility to solve the spillage. It also sounds like the 2nd breather is/was to allow for the baffling that is designed to keep fuel in the right hand side of the tank on right handers. Lee said unblock it as it's there by design, Tony said we block it off these days. Me? Going to add one way valve and see. Relevance of the baffles is also the possibility that it is my getting out of the car that rocks the tank releasing air from baffles, as noted when I did not get out and my brother released the cap, then the car did not start, but when I then got out and switched the cutout off and on, got back in it did then start. So was it the effective ECU reset or my getting out that did it? Next time I will trying getting out and in and we will see.

I may or may not fit the pump, it's for use or for stock as it quickly became apparent the part is becoming unavailable - indeed it IS unavailable except this Merlin upgrade component. Redline think the original may be from a Rover 100.

 

 

 

[nickh7]

I had a surplus pipe when I fitted my new Areo cap , I  followed Elie's advise and pushed the surplus hose under the boot floor so it could vent  back through to the side of the tank . I've had no issues at all , no fuel loss through corners , no heavy venting upon opening the tank .

[anthonym]

finally I hope to be home in a day or two (bit of a while since your post!) , must say I like that idea, maybe plus a one way valve since Ian has given me a couple. And tighten the nut to stop the leaks.