Benton

My old 420R (Bmw) diff used to have a pronounced whine at 60mph, 5mph either side the whine disappeared. Did it from new. Current 620R (Sierra) diff probably whines as well but you cant hear it above the sequential gearbox noise

Used a Momo Mod27 270mm on my old car for a while. TBH I only bought it because I saw it on Ebay half price and thought I'd give it a go, as at the time I also had a flat bottom wheel on another car. For road use I personally found it less than ideal when having to turn the wheel significantly, having to adjust your grip positions on the wheel etc. and certainly noticeable when parking, and therefore eventually reverted back to a "standard" wheel

Was in tin top going other direction, my dog wagged his tail though!

Loctite Teroson MS 9220 Only £29.11 at Amazon,..... Caterham £40.88!!

Update! So cause found ..... cream crackered immobiliser unit. New one being fitted .... more warranty parts Thanks for all the earlier investigation suggestions, at least it wasn't something I could have sorted easily myself.

You're giving Caterham ideas now

Since I'm currently having issues with my immobiliser (though it's a bit late now, since I've handed the problem off to Caterham), but just for better knowledge going forwards, does anyone know where roughly this relay hides under the scuttle?. Update - it seems apparently the relay(s) are contained within the immobiliser unit as a whole

Well that's certainly different! Presumably there's a "history" of this happening before, that Williams knew about, otherwise I would have thought you be very lucky to identify that as the cause of the problem

#40 As another check I disconnected the Caterham battery and hooked the wires up to my daily's battery, same result..... Switch on, gauges sweep, immobiliser light changes from slow to fast flashing...... waving tag does nothing Interesting to read in completely different thread and subject (misfiring at certain revs) possible problem with immobiliser relay, never thought of that one and not obvious to me at the time when looking around where it hides within the scuttle wiring spaghetti.

Yep, fuse checked OK, supply voltage to fuses Ok, immobiliser found but no obvious visible connector found (at least without having to disturb too many other cable ties/loom parts etc.), disconnected/reconnected ecu connection. Still no joy. Ran out of ideas so I've thrown in the towel . Managed to persuade the RAC to get the car transported to Gatwick. If it turns out to be it's something simple I'll kick myself!, we'll see.

So if anyone is remotely interested .... the immobiliser aerial does indeed have its own connector, which of course was perfectly sound. Beyond that connector are two (apparently) identical black wires that seem to disappear into the general electrical spaghetti abyss near the top of the scuttle, heading in the direction of the "fuse box", where I'm guessing the actual immobiliser is lurking somewhere nearby. Tomorrow's task for curiosity is to hunt down the immobiliser, you'd assume it has its own connector, .as well as checking the soundness of the overall connection to the ecu. Joy ....

Out of curiosity pulled it out .... no instrument (tachometer / speedometer) sweep plus the other fuses correspond OK to the diagram

Thanks Jonathan. In "normal" operation the immobiliser light goes out and the fuel pump primes it seems almost simultaneously. ​The fuel pump/sender unit has been in and out the car a couple of times by Caterham, so could possibly be a culprit. Whether a problem with the fuel pump side of things can affect the immobiliser disarming then I'm I don't know. I've checked the fuel pump loom as far as I want to go, a known problem is that the rear exhaust hanger can "chop" its way through the loom, thankfully there's plenty of distance between the two. Whoever last put the fuel pump back got a bit carried away with cable ties, plus the fuel pump module is screwed to the boot floor, so further investigating the connections to the fuel pump involves effort which I don't think is worthwhile, besides which the car is under warranty and so I don't want to "fiddle" to much. The only other area I haven't checked is to see if the immobiliser "aerial" wire actually plugs into the immobilser (and has come loose for some reason) or is it hard wired. There's only a couple of illustrations/parts listed on the Caterham website which include the immobiliser and main loom together so it's hard to tell. Further investigation will also involve a battle with the cable ties

620R Jonathan. Just for fun just checked the fuses (immobiliser and fuel pump) both ok, made a strange, hopefully totally unrelated, discovery in that according to Caterhams diagram/spec the fuse for the instruments should be 7.5A but mines got a 30A one fitted instead!

So just hooked the Caterham up to my daily's battery same result won't disarm. Now where's that whiskey........

Thanks Jonathan, I'll try tomorrow with some jump leads/another battery and see what happens. Of course if I can't get the fuel pump on/engine to crank in the first place then I haven't got a lot to measure

Time to get this thread going again with another "opportunity" ..... So last month I noticed occasionally the immobiliser light would start flashing whilst I was driving along!, flashing lasting for about a minute and then stopping. Car in the meantime ran perfectly fine. Used the car yesterday, ignition on and off / started at least a couple of times perfectly fine. This morning at home disconnected the conditioner, tried to start the car, immobiliser wouldn't disarm, kept the rapidly flashing state till it got bored and rearmed itself. Tried disconnecting/reconnecting vehicle battery, playing with inertia switch, spare key, messing with the "aerial" pickup wire etc. - nothing. No real reason to suspect vehicle battery (though it is 3 years old), reads over 13v when turning the ignition key to the "on" position (though of course it's not actually doing much at the time, no fuel pump, no engine cranking), besides battery had no problem cranking the engine over yesterday. The immobiliser is the standard Sterling (passive key) setup. Anything else obvious to check whilst waiting (not so patiently) for the Caterham truck?

Having owned a 420R and now a 620R my two pence worth ...., no science behind it and obviously just my personal views .... based on only road usage and only on measurements using my bottom, and the caveat that both cars were/are "standard" supplied by Caterham with no geometry/flat flooring etc. My 620R appears to be much more firmly sprung than my previous 420R too firm I believe IMO, and for me the factory springs don't appear to be particularly well matched to the factory 620 damper response for road use (which on the face of it is no surprise since it's essentially designed as a track car). Having said that given decent tarmac the 620 feels much more stable/planted when pushing on than my old 420 did, however when the going gets rougher shortfalls in the 620 setup start to appear. One of my regular routes features a road with a smooth surface but with a series of underlying small humps and dips where the road has been subjected to subsidence in places I'm fortunate enough to also own a Lotus Exige and when driving this road the Exige feels completely planted, you can feel the suspension really doing it's stuff. Driving the 620 along the same road up to a certain speed everything feels OK, but then trying to push the 620 at the Exige pace you soon become aware that the suspension is not "keeping up" with what's being asked of it, at times to me it feels it almost "floats" along for want of a better phrase, rather than follow the actual undulations, which can lead you into a false sense of security. I don't recall having similar experiences to the same degree with the 420, the ride being more "choppy" but feeling more connected, more of the time. Sorry if none of the above waffle helps you CtrMint ...... but in pure "bottom" terms for me my ex 420R and 620R feel completely different suspension wise when used on the road, with each having their strengths and weaknesses depending on road state encountered. I'll still take the 620 at the end of the day though

Having posed the question to Caterham over the last couple of months I have yet to be informed that an "official" solution is on offer/in production, or indeed any timescales ....

In my old car used a cut down portion of a cheap screwdriver handle epoxied into the throttle pedal "hole". Lasted no problem for ove4 16,000 miles.

Assume an appropriate steering boss is also required?

#52 No problem. Hope they get it sorted for you

IMO the clear lenses regardless of type of bulb (incl. the Caterham LED coloured fitted bulbs ) are pants in certain lighting conditions / bordering on dangerous having observed many examples . It's the first thing I changed on my current car. You're better off with clear led bulbs in the original coloured lenses if you don't go the "full" led (JAL or Caterham) route.

Hence my earlier question as to whether this solution is for the wider 620 community, guess I'll ask Caterham directly.

#46 Are they using you a "test bed" or is it now a tried and approved solution that they are going to offer to other owners?