Hi All,

I mentioned this problem in my 1.3 sensor locations thread but thought I'd post this as it's becoming more of an issue to detect!

Basically from cold start it will start first time as usual, but if you turn the car off before it is fully warm (eg. a minute or two) and try to restart it's a real struggle. Wait for it to cool and then it will start with some persuasion. Let it cool fully and first time again....

I've replaced the temperature sensor ontop of the thermostat and also the crank position sensor to no avail. The car had new spark plugs about 1000 miles ago, along with an oil change and air filter.

Anyone know where's best to look next?

When the engine is fully warm, can you read the engine temp on your dashboard..?

If not, your ECU should not have it to, and think that your engine is still cold!

Yep when the engine's warm it sits just under the half way mark, as it always has done

You could try splicing a wire into the brown/white one from the temperature sensor (do not put a break in it) and connecting it to the battery negative terminal.

Sounds interesting, I assume this means that the earth in the temp sensor plug could be the issue? Is it a common problem?

It's a four pin sensor, one pair of pins for the gauge and the other for the ECU. This is on the ECU earth side, we've sorted some cold running problems using this in the past, also an extra heavey gauge earth from the battery to body may help. I am more of the opinion that it is an inherent software glitch, where the ECU cannot get the fuelling 100% correct for some engine temperatures.

It may help and it's only going to cost you a little time.

May just be something simple like a partially clogged fuel filter, intermittant problem with fuel pump or incorrect valve clearances. Possibly the latter.

The other thing i reckon as a long shot thinking out loud is the temprenture of the air going in the throttle body/amount of air to fuel being too low and related to the fresh air flap in the filter housing remaining closed rather than open.

In general i am not keen on fiddling with engine sensors as i believe they only tell you so much. it is best to rule out the basics first

Right well an update...

I've replaced a split oil breather pipe, swapped out the inlet temp sensor for another one and it's still doing the same.

Which do people think I should try next, valve clearances or fuel filter? It's getting pretty annoying now!

Ill also try the earthing of the thermostat temp sensor soon

There's a lot of posts about sensor problems and I suspect there are weaknesses in the design of the Felicia electronics. Engine management systems were not mainstream 10 years ago and it's easy to get fixated. Mine's just had a full electronics diagnostics check and no faults showed up. However, this week I had trouble getting in because all the doors froze shut and when I eventually gained entry and drove away I realised that the back door had come open. I stopped suddenly and stalled the engine. On starting up the revs stuck too high. Turning it off and restarting put it right. The temperature gauge now goes to half way after ages sticking near to the bottom but no problem has shown up. Dare I say that? So long as glitches don't cause serious difficulties I'm coming round to the view that it's best to leave well alone. For those who enjoy messing with cars the Felicia has to be a great choice.

Is there a way of resetting the ecu?

Right well I've been reading up about valve clearances and apparently tight clearances can result in the symptoms I'm getting, has anyone else experienced this?

hi there - apologies not a frequent poster here but excellent site and much learned about my 1.3mpi felly...

I too have had exactly the same problem on two occasions - once when I stopped for petrol after less than a mile from starting from cold and a second time when I stalled it at traffic lights - again, less than a mile after setting off (stalling only caused by the fact I also have a Land Rover TD5 Discovery with slightly more low down grunt !!).

I've not done too much about the problem other than making sure it doesn't stall or stop until it's warm - tend to agree that it may be an ECU mapping / sensor design glitch as it gives all the impression of no fuel when you try and restart (best to have a good battery). Never a problem stone cold or warm, just this first few miles when neither one or the other. I would be tempted to try some "easy start" if I was really stuck or just wait a few minutes for the sensors to reset

Still the best "second car" we've ever had though....

If you even suspect the valve clearances are tight, check them! Other than starting problems, tight valve clearances cause poor economy, rough running, and even burnt valves!

Right well I've been reading up about valve clearances and apparently tight clearances can result in the symptoms I'm getting, has anyone else experienced this?

i recently had my Feli GLX with a valve clearance of 0.10mm all the way arround, and was getting realy bad gas milage, i cant imagine a worst valve timing thant what i had for the feli and i had no problems starting at all temperatures

if you have a little problem with clearance is not the culprit of your problem. i've done spark timing without a gun by turning the engine off and turning it on, good timing means it will start right away, bad timing would mean it would hesitate to start (but if you enriched the mix it would start right away) and realy bad means it would start, thing is, in that worst timing, the engine would run if it was alredy runing this is a great way to check timing with air/fuel mix, so if whe presume that the ECU is doing good air/fuel mix then what you describe point to a realy bad timing.

if you can, put a vacuum in you plenum and tell me the reading at idle and 2500rpms as well as how the needle acts... as well, take out the #1 spark plug and submit a picture of the firing end where you can see the electrode, ground strap, porcelain and at least 5 treads, like the pic i've submited

I might be able to tell you where the problem is exactly through a little reseach

Edited 14 November, 200817 yr by Cepheuz

Is there a way of resetting the ecu?

i dont have a multi-injection modle, but i've read that you disconect the batery cable overnight, also i've read to turn the ignition on without starting the car and leaving it on for 5min, i would try the latter before the previous, good luck

Well I didn't suspect valve clearances until it was suggested on here... and having changed the thermostat sensor, crank position sensor, inlet temp sensor and a split breather hose it's still doing it, so I thought I would go for one of the other suggestions from people on here. I'm increasingly suspecting it not to be a sensor problem. Trouble is with the car being at my girlfriends house and it being dark all the time, means it's difficult to look at it!

Gas mileage isn't too bad, but from what I remember of when I bought the car - not quite as good, but nothing too significant.

Thanks Cepheuz for the tips regarding ignition... plugs aren't that old but I did wonder whether to try another set, they were pretty cheap ones. I'll try and get a pic at some point and post it up.

ECU has been reset as I took the battery out to recharge it after it went flat.

Definately check those valve clearances! I would also ensure the plugs you have are the correct ones, as you say they were cheap. The correct MPi plugs are fairly pricey from what I remember. Can't remember the correct part number right now, but it's definately worth looking into.

Thanks Dave..

I was mistaken having checked old receipts... the plugs weren't that cheap (£12) but they didn't look as good a quality as the Brisk ones my Dad fitted to his. The electrodes weren't adjustable though and didn't need setting, is this correct?

Next step, I'll get the valve clearances checked!

Thanks Dave..

I was mistaken having checked old receipts... the plugs weren't that cheap (£12) but they didn't look as good a quality as the Brisk ones my Dad fitted to his. The electrodes weren't adjustable though and didn't need setting, is this correct?

Next step, I'll get the valve clearances checked!

yup, some plugs dont need the electrode set, but if you do i read in a page that skoda felicia uses 0.80mm though that is definetly not the problem in your car.

the important thing is to read the plug you alredy have, f you google spark plug reading you'll see how much information you can get out of the, combines with vacuum reading i belive you can pin point anything

My 1.6 SLXi has recently had its ignition timing changed slightly to TDC. It seems to go much better but before it's fully warmed up, which on a freezing day can take ten minutes, it's prone to stall when I slow down quickly. I'm trying to adapt my driving to take account of this. Fortunately, it restarts without any difficulty. I can see that being a considerable problem if it failed to do so. With an older carburettor set up I'd have just made a slight adjustment to the idling tickover and expected things to be OK. What you do with an electronically controlled system I don't know. Maybe it's worth looking at small changes to the ignition timing. The VAG engineer who reset it only took a couple of minutes with a strobe and eased back the cambelt cover to get access. My interest in vehicle DIY has long gone unfortunately. The car has been regularly serviced and has a clear computer readout for the ecu.

My 1.6 SLXi has recently had its ignition timing changed slightly to TDC. It seems to go much better but before it's fully warmed up, which on a freezing day can take ten minutes, it's prone to stall when I slow down quickly. I'm trying to adapt my driving to take account of this. Fortunately, it restarts without any difficulty. I can see that being a considerable problem if it failed to do so. With an older carburettor set up I'd have just made a slight adjustment to the idling tickover and expected things to be OK. What you do with an electronically controlled system I don't know. Maybe it's worth looking at small changes to the ignition timing. The VAG engineer who reset it only took a couple of minutes with a strobe and eased back the cambelt cover to get access. My interest in vehicle DIY has long gone unfortunately. The car has been regularly serviced and has a clear computer readout for the ecu.

wen you accelerate and release the pedal, does is backfire on the muffler? or,

when you accelerate quickly on you car, do yo hear tapping or popping noises from the engine? and,

Was it prone to stall before fully warmed up before spark timing adjustment?

Nothing like that. It starts first touch, runs very smoothly, accelerates well and is very quiet. The at rest tick over drops quickly to around 700 rpm. Unless fully warmed up the car now has a tendency to stall if you slow suddenly without decelerating through the gears. It did not do this before adjustment but very occasionally the rpm at start up would be too high and wouldn't reduce unless you switched the engine off and restarted.

Perhaps the cars need to be very finely tuned.

Nothing like that. It starts first touch, runs very smoothly, accelerates well and is very quiet. The at rest tick over drops quickly to around 700 rpm. Unless fully warmed up the car now has a tendency to stall if you slow suddenly without decelerating through the gears. It did not do this before adjustment but very occasionally the rpm at start up would be too high and wouldn't reduce unless you switched the engine off and restarted.

Perhaps the cars need to be very finely tuned.

what you are describing is poor vacuum in the manifold and/or lean mix, both can be caused by a disconected hose line, check all porto to/from plenum/manifold, lean mix has also two tell signs, 1 at start give poor/low rpm and unconstant idle rpm (it changes depending on load and heat) and loss of engine torque (it will still run smooth after warmup)

my bet (i put 50 down jajaja) is that you had a backfire wich release one of the hoses or you servo is leaking air from somewhere

high rpm at startup happen cus the mix is leaner (partialy open throtel wilst choke plate coses normal air pasage) producin X rpm at Startup to warm the engine, more air flow = more rpm at least on carb models

on fuel injected models is the same, injectors pump ot more fuel untly warm and throttel restrict air flow normaly, again, more air flow = more rpm

if im correct the adjustment that you did was increase idle via idle screw wen engine fully warmed, am i correct ?

The screw adjustment was to an SU carb from an MG 1300. Easy to adjust. Mind you they were a heap of junk. Lovely leather seats and walnut dash though.

I've not heard any back fires. The cutting out is only an issue on very cold days for about the first ten minutes. I suspected it might be related to the ignition timing. The car has fuel injection.

The screw adjustment was to an SU carb from an MG 1300. Easy to adjust. Mind you they were a heap of junk. Lovely leather seats and walnut dash though.

I've not heard any back fires. The cutting out is only an issue on very cold days for about the first ten minutes. I suspected it might be related to the ignition timing. The car has fuel injection.

wen ignition timing is off you eyther hear pops from the exhaust wen you de-accelerate with the cluch engaged ot knock when you accelerate, so if you head none, then the ignition timing isnt that far off, lots of people use strobe lights, i like to set mine with a vacuum cauge and for daily driver cars its not a crucial 0.00 degree thing

from what you say i'm still suspecting an air leak