Since I picked up my NC I have been struggling with the clutch / throttle balance when pulling away. The car tries to stall and quite often I have to push the clutch back in and feed in quite a lot more throttle before I can pull away.
Initially I thought I was just out of practise - my main car is an auto and my daily commute is on a motorbike so it has been about six months since I was in a manual car. But after more than a week I’m still struggling to get it right, something which has never happened before. I have been driving for 25 years and in any other car after a short while I have just ‘adjusted’ to the clutch biting point. What is also interesting is that my wife is reporting exactly the same thing - struggling to pull away smoothly and almost stalling the car.
My initial thought was a slack accelerator cable but then I remembered that of course the NC is ‘drive by wire’ so there is no accelerator cable. (By ‘remembered’ I mean looking under the bonnet, scratching my head, going off to read the manual and then feeling like an idiot.) So I looked up clutch adjustment but all the information I can find (including the Haynes manual) focuses on adjusting the free play in the pedal, not the biting point. From what I understand the clutch is supposed to be auto-adjusting.
The clutch appears to start biting about half way up the pedal travel. What would be nice is to have it biting closer to the floor.
Is it possible to adjust the clutch? Or is there another cause behind what I am describing (hopefully with a fix)?
Hi pagers. The mk3 engine has some pre tuned flat spots. One of these occurs when initialy pulling away. It disappears if the fuel tank is full of high octane unleaded petrol. Hope this helps. Chris
Adjusting the free play , will adjust the perceived bite point. It’s not easy to access the lock nut and adjustment rod though, Mazda does give some recommended tolerances for the amount of free play.
The ‘bite point’ you describe seems unusually high on the clutch travel - the more usual complaint is that the clutch needs to be’floored’. In isolation, your symptoms might suggest a very worn clutch disc?
Hi Chris, not sure I understand that. Are you saying that I have to always keep the tank brim full of high octane (which doesn’t seem to make sense) or that running it on high octane (which I am doing but I guess the previous owner did not) will fix the problem?
Stevieh - thanks, I did see the instructions to adjust the free play but was worried that by using that to adjust the bite point I would mess with the free play too much.
I’ll see what results from running a full tank of super-plus through the engine and then look at clutch adjustment. I’m also considering getting a re-map on the engine anyway so that would probably help.
Hi sorry for the confusion. What I am suggesting is that topping up a 3 quater full premium unleaded tank with a quarter tank of super unleaded petrol, is bit like topping up a lemonade with bear. You get a watered down effect of the alcohol. So a full tank of the right stuff has a greater impact on engine performance.
Yes, if you can get to adjusting the clutch peddle free play, and the peddle stroke. They will help to ease the problem.
Also, how about cleaning the throttle body inlet, where the air filter casing attaches to the throttle. And spray electrical contact cleaner on to the air mass filter sensor. Cheap to do and worthwhile, especially if a remap is in your planning.
Thanks folks. I’ll try all the suggestions and see how it goes. Might take a while as the car will mostly get used for short, local runs so I imagine getting the engine to remap itself for the new fuel will be a slow process. But one of my top priorities is to have a good clean under the bonnet so cleaning out some parts while I am there seems reasonable.
I have the same ‘issue’, which I don’t believe to be an issue having looked through the interweb. Without much throttle (and especially without any), starting to find the biting point results in a dip in revs as if you’re about to stall?
I’ve found feathering the go-faster-pedal while at junctions before pulling off, or on hills etc. helps a lot. I’m used to riding the clutch from driving a diesel Clio prior to my MX5, as it would hold itself on hills etc. The ‘flat spot’ has re-taught me to use the handbrake to prevent unnecessary wear on the clutch.
I have had no issues actually stalling, even revs do dip a little.
I know exactly what the OP means. I stalled my NC a few times after I purchased it, and it certainly seems to need rather more revs than many cars to prevent it stalling when starting off. Might be something to do with the engine mapping, but you soon adjust to it. Potential clutch wear does worry me a bit though.
Had mine around 3 years and yes it did tend to feel like a flat spot (hestitation) when pulling away. Anyway you get used to that the more you drive the car but it did help when I adjusted the bite point of the pedal, as in the link above. It only takes a minor adjustment there, a bit of trial and error, don’t over do it. I suppose the problem there is getting at that adjustment, it’s not easy and no good if your bones are old like mine, but I managed it.
It doesn’t even bother me these days, quirks of the car. I have another car and I can most likely say that has a few quirks too, like it’s FWD so needs to be driven differently, the clutch is very fierce on that and it’s taken me 2 years to get used to that and must say it’s got a slicker gear change than the Mk3 but is in no way as enjoyable to drive.
My 1.5 mk4 is very flexible and virtually impossible to stall, not like the Ford Kuga which has a pig of a flat spot pulling away, all cars have their idiosyncrasies just have to get used to them, not easy when swoppin between cars all the time though. Hey the Suns out! Time for a drive, one advantage of being retired/old!!!.
Here is something to try, it has been mentioned, and it worked for me.
When I bought my NC it also had the flat spot and I needed to play with the revs and clutch a bit to get away, even when it was fully warmed up.
But I was also familiar with this problem on my old Vectra which was a reluctant pig on regular unleaded but a smooth and willing flexible dream on V-Power, and the same story with sharing the driving on a good friend’s '05 Focus.
So first re-fill on the NC I went with V-Power and the flat spots vanished and the fuel economy improved from 35mpg to 39mpg (from miles per fill). The only time the flat spots have ever returned was after I was forced to put in a tankful of regular from the only garage available before a long trip home.
My experience is virtually identical to that of Richard FX above…
It loves V-power or similar and sulks when fed an inferior diet! The anti-knock sensor will have adjusted the ignition timing to optimise the higher RON number fuel, and the later (retarded) ignition timing from a regular fuel will tend to give a flat spot (or three…)!
Like I said in another recent fuel thread…
‘Who buys an MX5 for its economy anyway…? Feed your best car the best fuel, and it will love you back…!’
OTOH, if you’re on 97RON + already, then it may need new plugs - IME they don’t last the full 60k as advertised particularly if used on short (rich) runs.
The clutch itself may be getting a bit tired, if the bite point is more than halfway up the travel.
First full tank went in the car over the weekend - 97 octane. As the car came to me with very little in the way of maintenance history and 94k miles on the clock the first thing I did was treat it to a full service.
Plugs
Oil & filter
Air filter
Coolant
Gearbox oil
Diff oil
Discs and pads
It wasn't cheap but at least now I know the car has had all the boxes ticked and I can keep up a proper maintenance cycle from here.
I had come to the same conclusion after reading on Miata.net that one turn of the rod gives 1/10 of an inch of movement in the pedal position (so about 2.5mm)
It might be my imagination but it already feels better after a few days of super-plus so that may be all I needed.