620s - Clutch seems to go ‘floppy’ occasionally when depressed & stalls when cold

[Phillip Meyer]

Hi,

I picked up my new 602s (well, it's new to me, it's the first 602s they built aparently) from Caterham Cars, Gatwick on Monday.

I have noticed that very occasionally when I press down on the clutch it seems to go 'floppy' with no resistance, almost as though the clutch cable has snapped but it hasn't. I can't seem to change gear easily until I release the clutch and depress it again, then it acts like normal.

I have also noticed that when I start it in the morning (it's garaged overnight) the engine starts but if I even touch the accelerator pedal the engine will stall. This morning in stalled almost immediately after starting but then started again without issue. If I leave the car for a few minutes to warm up everything works.

The car is under warranty so I will email Caterham Cars but I thought I would check to see if anyone here has experienced similar or has any thoughts on the cause?

Phillip

[ScottR400D]

It's a hydraulic clutch so it sounds as if there's an issue in the hydraulic system. Could there be air in there and it simply needs bleeding? Or maybe an issue with slave or M/C seals?

I believe CC offer a hose extension for the 620 to facilitate bleeding so an easy job if that's fitted. 

[ScottR400D]

Can't really help with the stalling but none of the models seem to be too reliable, in that respect, straight from the factory. 

I'm sure some other 620 owners will be along to help soon!

[Benton]

From experience the cold start/stalling is probably due to a combination of incorrect adjustment  of throttle position sensor / failing lambda sensor, or less likely incorrect map set up.  How does the car run on part throttle when warmed up?
If it's all set up OK you should be able to use fifth gear at revs less than 2000 rpm doing a constant speed and still be able to pull cleanly away with gentle pressure on the throttle.  Also what's the fuel consumption like, does it seem to be running very rich?  Again when set up correctly you can get 27/28 mpg under normal road use from my 620.

Clutch s/b hydraulic not cable, sorry never had a problem with mine.

[Phillip Meyer]

I have used up 3/4 of a tank in 2 days (Gatwick to Westerham and a couple of shortish school runs). While I always remember my old Caterham being very smelly, this car has a tremendous smell of petrol (it's all I can smell for hours after driving and I have a terrible sense of smell).

I would also say that the accelerator is very lively, a tiny touch brings the revs right up but I was assuming that this is just normal. I'm actually struggling a bit with pulling away, I assume it's just that I'm out of practice but I am either bunny hopping when I pull away in 1st or wheel spinning off (often similar moving into 2nd).

I wonder if it is running very rich. I am about to head out to Thundersports in Oxted so will give 2000rpm in 5th a test.

Thanks for everyone's responses.

[pgm]

Hi Philip

Welcome to the world of 620 ownership. I quite understand that it is under warranty but if you would like to chat through any issues for advice please feel free to contact us at the workshop on 01403 713626 as we have dealt with a fair number of 620's recently especially with running and over cooling problems.

Kind regards PGM

[aerobod - near CYYC]

It should not run rich enough to smell petrol, in fact the catalytic converter will be quickly damaged if it does. It sounds as though either the lambda sensor is not functioning correctly or there is a problem with too much fuel delivery due to, for example, the temperature sensor failing.

[Baggiebird]

Lovely looking car from pics on other thread and will be tremendous fun when fully sorted.  I'm thinking that Caterham's mechanical checks need improving though especially for a car near the top of the range?
 

[Benton]

Unfortunately you cannot always rely on Caterham's  fuel gauge accuracy, even though mines been "recalibrated" by Caterham when it reads halfway into the red section there's still at least a usable 5 litres left in the tank  (not including the approx 5litres that is unusable due to the tank shape/fuel pump pickup position.)  The only accurate way of calculating mpg is by brimming the tank, drive, note mileage and re-brimming.

Aerobod (James) has far more experience in these matters than me but if we're starting a sweepstake I'll put my money on a duff lambda sensor for starters. You need to get somebody to hook the car up to a copy of the diagnostic software Easimap to show what the various sensors are doing.

The throttle is sensitive by nature but if the cars running right that shouldn't prevent you from pulling away easily without having to wildly slip the clutch or give it "loads of gas", or end up doing a kangaroo impression.

If you think it's running excessively rich then an obvious quick check (though you could argue why you should be doing this with a car under warranty and less than a week of your ownership) is take a look at the state of one of the spark plugs for soot build up.

 

 

[Phillip Meyer]

Thanks for all the advice.

The car runs comfortably at 2,000 rpm in 5th gear (and significantly lower revs) and will accelerate off fairly nicely (but I don't have anything to compare it to).

I did email Caterham and had a call back but I was tied up, they are going to book it in a take a look because of the clutch.

I will also give PGM a call and maybe drop in to visit them. I'm keen to get an outside opinion on the car (which I am very happy with) but I'm also really interested to see/hear what PGM do and can offer. I'm not sure if the car has a cooling issue or not (again nothing to compare it to) but the temperature does tend to hover around the upper-middle-left of the guage.

I will try looking at one of the spark plugs and see if that shows anything.

I had a quick look at SBD motorsport, is it worth buying a connector and the Easimap software? I'm not sure how easy it will be for me to extract the info I need in a fashion that I will understand it. (I'm a fast learner but not sure I have the bandwidth for a long, steep learning curve right now).

[Benton]

Personally given your short ownership of the car I'd insist when you take it back to Crawley for the clutch issues they thoroughly check out your reported fuelling issues (they have Easimap) and insist they properly road test the car (yes I know this should have been done prior to your purchase but for some reason it appears not to!)  If you can add further evidence like a clearly sooty spark plug then all the better.  If the cars under warranty then it's their responsibility to sort it rather than you having to chase around / incur any additional expense.

If you're then not happy with the Crawley result (get the TADTS response) then rather then spending the money on an Easimap lead, then as you suggest let PGM carry out a full reality check on the current state of the car.

Looking at PGMs upgrades/service offerings, they obviously offer a number of tried and tested alternative solutions for better tuning / cooling control  / chassis setup etc. which in the longer term should give you an overall better car, some of which I admit I'm quite tempted by.

However (and I don't think I'm doing PGM a disservice here) these upgrades aren't free at the end of day, and some of the PGM modifications offered potentially could affect your Caterham's existing warranty (if you're  bothered about this) which of course you'd have to verify.

Hope you get the car sorted soon whatever route you end up taking.
 

 

[Phillip Meyer]

Thanks all. Caterham have been super-helpful and I am taking the car to them tomorrow morning.

They did push back on the stalling and petrol smell ("it's a high performance engine...") but we will see tomorrow. Incidentally my mother used to be the operations director at Brands Hatch (30 years ago) so I have spent a lot of time around and driving high performance cars. In general they haven't smelled quite this strong but we will see and the smell is not a deal breaker, it adds to the charm!

I will probably call or use this as an excuse to take a drive down to PGM next week. I'm really interested in what they can offer, possibly a reality check would be a good investment as if they do turn up any issues I can take that back to Caterham Cars.

 

[7 wonders of the world]

They did push back on the stalling and petrol smell ("it's a high performance engine...") 

They don't do themselves any favours making comments like this.......

 

[ScottR400D]

I do wonder how a petrol leak or just blowing fuel out of the exhaust contributes to 'high performance'.

[SM25T]

They all do that sir ! Like hell they do.

[Benton]

and this 

 (first two minutes)  

[krisfl]

I'm not a 620 owner, but have the smaller (lighter engined erhum.) ford Sigma. They don't have any choke mapping in the ecu like every other car, so even they can be grumpy on a cold start. Nothing like petrol ped's vid mind. If the 620 is the same it won't help! So on the cold start point at least, perhaps to a point TADTS? 

[aerobod - near CYYC]

The MBE ECU is perfectly capable of compensating for cold start conditions, it has compensation graphs down to -40C and up to 130C coolant and intake air temperatures. There are also various cranking conditions that can be adjusted for and plenty of scope for all sorts of open loop and closed loop lambda operation. It is the same ECU software that has been used in cars such as from Noble and TVR in the past. It is only a matter of effort to get the mapping right in all operating conditions.

[pgm]

Hi Phillip

You are most welcome to pop in for a chat. We can explain about the issues you mentioned although I do think you are wise to give Caterham the opportunity to sort out your warranty issues especially as you have only just collected your car. Do give us a quick call before making the journey as Andy (my son) who will explain all, may be in and out of the workshop next week.

Kind regards Colin (PGM)

[john milner]

I don't think that a modern engine set-up for road use should leave a petrol smell from the exhaust. If that is where the smell is coming from it has a tuning problem and is possibly dangerous. While still in warranty it may be worthwhile getting the emissions checked at a MOT station.

Something is probably leaking. I had a similar experience when a fuel level gasket rotted on top of the tank.

[ChrisC]

Lets not speculate, lets let CC check.  

Most likely its the much discussed 620 over cooling issue, causing the ECU to resort to warn up settings which is causing the petrol smell.  CC did discuss a fix on the evening web chat a few months ago, but there are is also a fix offered by PGM (as above).    

I bet it would pass an MOT (and IVA) if its up to temperature, and the cat is warm (5 min at 3-4000 rpm should sort that).  This is exactly how its tested at all the IVA tests (only 3) I have been to.

As for other models with cold starting / warmup issues, In my experience (4-5 Sigma 150, two 360R, and 4-5 420R, and a Supersport R, all stock setup) it always boils down to throttle stops/cable adjustment/throttle position sensor setting combination.  It takes time to find that balance on a individual car, and that time, it seems, isn't always lavished on fixing this issue in a commercial environment.  Also a combercial environment rarely get to see engines start from cold. 

I have also found throttle adjustment made within the first few miles isn't always appropriate after the first 2000 miles, and this has been the case for both my 360R and 420R I have built.  Currently my 420R will hunt at idle if the coolant is lower than 15C, its only for a few seconds until the coolant is over 15C.  I didn't start this behaviour until it reached 1400 miles. I will fix this over winter.   However when it was first built my 420R, before I made my first adjustments it would hunt at idle until it reached 40-50C (but before the lambda sensor kicks in at 60). 

There are excellent specialist that can makes these adjustments, or adjust the ECU to your specific vehicle.   Or (like myself) there are armatures that will gladly give their time to fellow club members to resolve these annoyances.  Just don't suffer if you are annoyed with your engines startup. 

 

[Phillip Meyer]

I took the car to Caterham Cars this morning and you guys were correct, there was an issue with the Lambda sensor which has been replaced. They also bled the clutch.

I have to say that the car actually seems to drive much better now, I'm not sure if it was the clutch bleed or the sensor but it is much smoother in general but noticeable pulling away in 1st and moving into 2nd.

I will still speak with PGM and see if we can improve the cold start. Not sure if I have a temperature problem, I do notice that the temperature generally sits just below 60 but does head up to the top-right of the dial (over 80) if under stress.

[aerobod - near CYYC]

Hi Philip,

You need to ensure that they rectify the car sitting below 60C in normal operation, this may have been the problem that killed the lambda sensor to begin with and may also destroy the catalytic converter in the medium term due to an over rich mixture. Unless they have changed the mapping in the 620 to use a lower temperature for closed loop operation, the mixture will always be in warm up mode below 60C, as this is the default temperature set in the MBE ECU.

The car should reach 60C coolant temperature within about 5km / 3 miles of gentle driving from start in all weather conditions and stay above that temperature for the whole of the rest of the journey.

[Phillip Meyer]

Thanks, that doesn't sound good. It has to go back as I am still having an issue with the clutch so I will keep an eye on the temperature and ask them to look at that. They have been very good and will fix whatever it needs, they think clutch has either a problem with the clutch master or slave cylinder (the later will need the engine out so good job it's under warranty).

in terms of cooling I will speak to them but also give PGM a call next week and see what they can do.

[nutty7]

Keep checking the clutch fluid level and colour. If it's turning dark chance there's a seal on it's way out, any fluid loss could indicate a very slight leak. The clutch will work on infrequent gear changes as the hose line refills but if you press the clutch repeatedly and it goes soft you have a leak.