Tony Leigh

Steve, I spotted the alert bell thingy. Will lookout for more updates in future. Regards, Tony

James, my Caterham handbook quotes 5.1L for Cooling system with heater. When flushing my cooling system and re-freshing coolant that seems about right but haven't measured accurately. I'm never sure I have drained the system fully and always seem to need a small top-up once engine has been run-up and fluid has circulated for a few minutes.

Luke at Team Leo's can certainly access ECU's and carry out mapping of the engine. I recently had my 2019 420R re-mapped by him. As others have said I don't think the problems you have encountered are anything to do with the ECU. I have had problems with my speedometer becoming erratic and this was due to the reluctor ring on the driveshaft moving and the teeth not being seen by the sensor, the gap between the sensor and reluctor ring is also key. That's where I would look with regard to the speedometer. I'm not sure about the rev counter. I guess if both issues occur simultaneously then that points to a common problem not related to the reluctor ring/sensor, but I'm not sure what that may be. I'm sure Luke would be able to solve it, but if it's still under warranty the original dealer should really sort it out. As I'm sure you know intermittent problems are more difficult so trying to record when the problem occurs - high speed/low speed or high revs/low revs, etc., may help dealer replicate issue. Good luck.

Reply to #31 Jonathan, I hadn't noticed the warning light coming on. When the car is not in use I use my battery isolator and over long periods put the battery on a trickle charger. I noticed that it was a bit more laboured when starting the engine but no other issues and just assumed it was an age issue (the battery is 3.5 yrs old).

Apologies for not giving an earlier update, but the problem with my car turned out to be the ECU. I did a bit more investigation myself in late November and using a NOID light diagnosed the problem to be no signal to no.1 coil pack. As others had mentioned that the wires in the connector to no.1 coil pack sometimes fail due to vibration I purchased a new engine sub-loom. When it arrived I eagerly fitted it expecting my misfire to be cured. Alas this was not the case. At this point I decided to hand my car over to an expert, so I contacted Luke Stevens (Team Leos). I wasn't in any great hurry as I don't use my car in winter, so it wasn't until a couple of weeks ago that Luke took my car. I spoke to Luke this week and he said that there is a fault with the ECU, most likely the driver for no.1 cylinder. He has seen this before but it is fairly unusual. He has also found that the Lambda sensor has failed along with the alternator, and the battery isn't in great shape either, so quite an expensive week. I knew the battery was starting to struggle so that wasn't a huge surprise. It is possible that the Lambda sensor failure was exacerbated by running the car with a misfire (I had no choice but to drive it home following the failure but my subsequent 'testing' when trying to find the problem may not have helped). The alternator is a part failure, it only charges at high revs and doesn't charge at low revs (<2000). Luke tells me that this is often as a result of vibration from the Duratec causing some of the windings to break. I haven't picked my car up yet, and I haven't asked how you can specifically diagnose the ECU fault as opposed to the other possible issues but I imagine this involves interrogating the ECU which I don't have the connector or software for. In the process I did learn about NOID lights which are 12v lights that you can connect in to the engine sub-loom connectors and see whether there is a pulse to the coil packs or injectors. I'm not sure how much this helps others (MTW) but that is the position with my car. All part of the 'fun' of owning a Caterham, I guess.

Thanks John, I had another quick look today, swapped coil packs between 1 & 2 and carefully checked wires, terminals, etc. There is still a temperature offset of circa 50C between no.1 and rest. But it does increase consistently, i.e. just after starting temps maybe 100 for 2-4 and 50 for no.1 then after a few minutes temps rise to 140 for 2-4 and 80 for no.1. Tried moving wires but no obvious change. Checked temp at different points on primaries and as expected they do vary but no.1 seems consistently cooler. Once up to temp (coolant) the engine idled fine, so I really need to take car out for a drive to see what it's like under load, hopefully will get a chance to do that sometime this weekend.

James/Sam, Thanks for your comments, the suggestion about swapping coil packs is a good one and fairly obvious but not one I had thought of (I had a stressful day yesterday so wasn't thinking very clearly - that's what I'll blame it on, anyway). Will give that a go before swapping TPS as I can't see how a faulty TPS would cause a problem with one cylinder and unless there is something amiss with my temperature gun or measurement it does seem to point to a problem with that cylinder.

Reply to SamC #14. The new TPS has arrived but I haven't fitted it yet. I did run the car up yesterday and measured the exhaust primary temperatures with an infra-red thermometer. No.1 primary (nearest the front of car) was running significantly lower at circa 60C, with no.'s 2 & 3 at circa 130C and no. 4 slightly lower at circa 110C. That made me think there is a problem with the coil pack, I removed the spark plugs from 1 & 2 and no.1 seemed to have liquid on it which I presume is petrol, no.2 was dry but a bit sooty. I carefully checked the wiring loom around the coil packs and TPS and can't see anything obvious but most of the wiring isn't really visible as it's covered with insulation type tape (I am sure there is a specific word for this tape but I'm sure you will know what I mean). A lot of our area members use Luke Stevens at Team Leo's as he is a very knowledgeable specialist (I have used him myself in the past too), so I am thinking I may resort to taking it to him to have a look. I could change the TPS but I can't see how this is adjusted as the screws look they just bolt in a fixed position so unless I am missing something the only option seems to be to change the throttle stop which doesn't seem the right thing to do, or as others have suggested changing settings within Easimap software which I cannot do. Changing different items may be the only way forward for me which feels a bit too much like random trial and error with the added jeopardy of generating other problems along the way if I get something wrong, hence why I am leaning towards asking Luke to have a look, but I do appreciate everyone's comments.

Thanks Sam and Andy. I will try the new TPS when it arrives in a couple of days and see what that does and then investigate other possibilities if not successful. Not too sure how easy it is to inspect silencer internals without endoscope as only have smallish (relative to overall diameter) inlet/outlet although I guess a major obstruction may well be pretty visible, but hoping new TPS solves problem.

Thanks SamC and JV. Cables to TPS look fine, so I have invested in a cheap replacement to start with as suggested by Sam. One further question - when replacing TPS are there any things to watch out for or is it just a simple case of unbolting and inserting new one - I just recall from other bits I've read that setting up TPS is quite an art but have never done this myself (yet).

Thanks for all your comments. I checked plugs this morning and they don't look too bad maybe a bit more sooty than I would expect. I disconnected lambda sensor and went for a short run, no better unfortunately. Exhaust note has changed (I noticed this when the problem occurred but re-confirmed it this morning). Best way I can describe it is that is more boomy and the car just doesn't want to go, occasional stall when coming to junction off throttle and, may be my imagination, but seems to maintain same speed (60 mph in 4th) at lower revs than before. I guess symptoms are a function of incorrect fuel/air ratio. So looks like it's the TPS that isn't working. I live near Kings Lynn and it is our area meeting (Carrotland) next Monday so will see if anyone there can help further with diagnosis.

Today I took my 2019 420R out for a short blat and after about 40 miles whilst heading back home I thought I could smell burning and then the car started to run roughly. It was only a few miles back home and during that time the engine would stall at junctions when idling, although it did re-start, and was down on power. The water temp. and oil pressure looked fine. When I got home I had a quick look at the engine but couldn't see anything obvious although the rear section of the side exhaust silencer/cat (I have a rear exit exhaust so the cat isn't separate) was very hot, and after several minutes when the front part of the silencer/cat was cool to touch the rear part of it was too hot to touch. This may be normal as it's not something I've paid attention to before and the rear part has shown more discolouration (I assume due to high temperature) for some time. The car has done around 4000 miles from new. I've searched the forum and can see posts about failed sensors such as the lambda sensor or TPS, which have caused running problems. So my guess is that the engine started to run rich due to a failed sensor, probably lambda (?), resulting in unburnt fuel passing through to the exhaust and burning there. I may be wrong in my assessment but would appreciate the thoughts of those who have more experience/knowledge than me with suggestions for fault finding/resolution. I don't have the cable or software to interrogate the ECU but I do have a multimeter.

Jonathan, Thanks for sorting photos- you did get them right. Part of high cost is unit is supplied with a new oil cooler (which I don't need). I tried to just source radiator on its own but that doesn't seem possible even via a local specialist who buys lots of stuff from CC. Contacted original manufacturer (PMA, Leicester), but they only supply via Caterham or their dealers. I contacted Radtec who were really helpful and offer a test and repair service with potential to supply a new (non Caterham) replacement if unrepairable. So, my plan is to send off to Radtec and see what they say. Converting to old style does require a new (different) oil cooler and hoses (I think) so don't think it's worth exploring that option at the moment.

I know there have been many radiator posts over the years and I have read quite a few recently but thought I would start another just to get any current information/thoughts from everyone. My 2019 420R SV has developed a leak which I think is coming from the core near the bottom just above the oil cooler (my rad/cooler part no. is 30C064C-R300). It is one with the oil cooler attached to the bottom of the radiator. I spoke to Caterham cars parts dept. and the person I spoke to was very helpful and told me my design is no longer available and I need a slightly different one (part no. 300C0004A) with 2 additional brackets (part no. 300P0063A). The radiator is £682 and the brackets £3.10. I know there has been quite a bit of discussion about vibration and cracked welds but I don't think my problem is a cracked weld. I am interested to know which way to go, either new CC parts, or a repair, or supply from someone else. I saw mention of a company called Alicool a few months ago but it appears they went into liquidation in May 22 and I have not contacted Radtec yet but their website shows no radiators available for Duratec engined sevens. I will try and attach a couple of photos, apologies if they appear wrongly orientated as I know that occurs quite a bit, but I'm sure someone will sort them if I don't get them right. More importantly I will be interested in views as to the best way forward Tony

The suggested route for the Carrotland PCR 150 route has been uploaded on to blatmaps and the link can be found here https://www.myrouteapp.com/en/social/route/5209234?mode=share The route is as follows Poringland - Ranworth - Oulton Broad - Southwold - Thorpeness - Ashbocking - Thetford - Elveden. We plan to start at 10.00 am on Sunday 26th September from Poringland Community Centre. For those that want coffee / bite to eat / toilet stop, I have spoken to the Railway Tavern which is very close to the community centre (shown on route) and provisionally booked for 10 people to stop there (this is just a nominal number as they wanted an idea of likely numbers - they can accommodate more or less). At the finish at Elveden Inn we need to confirm those who want to eat as soon as possible. Please let Steve Wright / Kingsley Young - AR's for Carrotland, know if you would like to eat there.