Hi all,

I've had some deja vu with my T reg Felicia 1.3 this week around the starting-stalling-not starting anymore thing it does when the weather turns cold! Everyone was real helpful last time round (last xmas) and replacing the thermostat seemed to do the trick. However... (deep breath)

Last weekend drove into town, came back after 45 minutes and the car simply wouldn't start. I called the AA out - he cleaned the spark plugs which were totally cacked up and noticed that on unplugging the temp sense cable the car started no worries.

Fine - temp sensor has gone, so engine is flooding, hence dirty plugs = new temp sensor :rotz:

Then - I noticed that the coolant reservoir was empty, although I'd only topped it up a few days before. We found it was pouring out of the hose attached to the water pump. Mechanic fixed this up, filled her up with water and ran it til it warmed up so that the valve opened in the thermostat so he could make sure it had enough water in.

But! The valve didn't open, even after about half an hour; plus the fan didn't come on. He turned the engine off and gingerly opened the thermostat housing - cue all kinds of cool bubbling and smoking effects - the valve just wasn't opening. So, he hacked it off and replaced the housing so at least the coolant is moving around all the places it needs to. Need new thermostat :(

Except! It wasn't getting up into the dash - the blower in the car was still blowing cool air and he found there was an airlock in this part of the system which he cleared pretty easily. He followed me home as he was concerned that the car might overheat, but it was fine - ran ok, temp needle bang in the middle, hot air blower just toasty.

So... I've had a diagnostic run and it's come up with the Lambda probe. The guy at the garage suggested that if this is reading wrong then the resultant wrong mix of air and fuel could be the root cause to all these ills. But he also said if it's running ok (once I replace the thermostat) I don't need to have it fixed. :confused:

I don't really know anything about cars at all so I've been reading around the site here and I noticed a few other interesting points around Felicia's failing MOT's due to high emissions and this possibly being linked to the Lambda probe.

Well, we nearly had to scrap this car cause it was failing it's MOT on emissions in June (our saint of a mechanic spent three days soaking various engine parts in diesel to clean them up and get it through) and we had resigned ourselves to replacing it next year as we didn't think it would pass again :(

Could a duff probe be responsible? Sorry for the long post - thanks for reading and for any advice

If the car will run, get the mechanic to put a voltmeter on the Lambda probe; out of range voltages will confirm that the probe is faulty.

Sounds like there are a number of things here.

1) Coolant issue. Get this sorted; replace the thermostat and then see where you are with that. Getting air out of the 1.3's coolant system is a piece of cake - just remove the temp sender when you fill the header tank up, and squeeze the bottom hoses a few times as you fill. You have enough water in there when it comes out of where you've removed the temp sender, and putting it back in is quick and easy. There may be a few small bubbles in there, but I've never had a problem with significant coolant level loss doing it this way, and I've needed to do it a LOT in the past.

2) Spark plugs - when you say they were "cacked up", were they black and wet-looking? A common failure is the temp sender (and the dash reading is done by a separate thermistor in the same sender unit, so it's possible the dash will read OK while the engine gets the wrong message), so change that while you're doing the thermostat

3) Lambda - as Ken says, you can get a meter put on it when it runs (and is up to temperature) and you should see output voltage from it on the appropriate pins, and when you blip the throttle it should alter as the accelerating mixture will be rich and the over-run will be weak. If you can get a vag-com cable on there you can read the faults from the ECU easy enough with a laptop, it makes this a lot less like guesswork.

What did your mechanic do to get it through the emissions test previously? Soaking things in diesel doesn't sound ideal, what was it failing on?

Soaking stuff in diesel is a known way of freeing up siezed components; I'd agree that Gunk or similar is a better way of cleaning them though.

Hi both,

Thanks for your replies

Lambda - this has been picked up by running a computer diagnostic so it seems fairly certain there's something up with it. djaychela - is that what you meant by using a vag-com cable?

If so, I took it in on Monday and the computer came up with five faults (including temp sensor, funnily enough) but the garage suggested resetting it and then checking it again the next day after it had run a few miles. Doing so the computer came up with just the one fault (as the mechanic had predicted) and that was a faulty Lambda.

The question is really two fold

1) Is it possible the faulty probe is contributing to all the different issues?

2) Do I need to replace the probe if it's not? (Even though it's duff!)

Spark plugs - they were black and, to me, looked kinda dry - it seemed kindof powdery, like charcoal if that makes sense? Only saw this for a few seconds before the AA guy cleaned them off. He suggested this could be related to the temp sensor but as I'm replacing the thermostat and housing doesn't that include the sensor anyway?

Thanks for your tips on the coolant too

RE my MOT - I don't really know what the mechanic did - my Dad pretty much sorted it out and did all the dealing with them. I'm gonna get in touch with them and see if they looked at the Lambda at all.

Good news - cos I only replaced the thermostat at Christmas my dealership is gonna replace it free of charge

Soaking stuff in diesel is a known way of freeing up siezed components; I'd agree that Gunk or similar is a better way of cleaning them though.

I know that, Ken. But I can't think of anything that would help with emissions that you'd free up....

OK, well if the lambda is coming up as faulty, then you'll probably want to replace it. BUT it may not fix everything; the lambda isn't used on full throttle and below certain revs, it's more for cruise fuelling, so you may find that it doesn't fix everything. Without knowing what it failed on before, it's hard to say what could be wrong. People tend to over-complicate things, when often it will be something simple, so it's best to make sure all the obvious/simple/cheap things are covered before moving onto the crazy stuff.

Spark plugs being black and dry would sound like it's running rich, which the temp sensor would make it do.

No, the sensor isn't included with the thermostat. Get the "Mk 2" thermostat that Jorily sell - it's MUCH more robust than the originals, and I've yet to see a 1.3 plastic-housed thermostat that hadn't failed. Change that and the sensor, put a new set of plugs in and see how it goes from there. Could sort it all out.

Ok, thanks

I was gonna pick up the thermostat tomorrow and hopefully do it over the weekend. Was gonna get the official Skoda part as they've agreed to replace it for free (see my last post) - is the Jorily one worth £20 if I'm getting the manufacturer part for free?

Also, the reason I say 'isn't the sensor included?' is cos I'm talking about changing the whole housing and the sensor is the doo-dah in top of there isn't it? (Apologies for the imprecise language!)

If that is the case do you think it's still worth changing the sensor anyway? This one seems to have developed problems in only 10 months after all (as it was the entire housing I replaced last Christmas).

Again, massive thanks for all your help I really know next to nothing, but I'm warming to the subject! This is the only car I've ever owned - a hand me down from my parents - and I'm beginning to want to fight to keep her running! Might take a trip to the Haynes website....

Well, if the one you're getting is the "original" one, then I'd say it's not worth tuppence. The jorily one is sturdy and well secured. I've had about 10 MPi engines through my hands, and EVERY single one has been broken, thermostat-wise. And given that yours was replaced 10 months ago and has died, you already know what you need to know.

The sensor is fixed into the housing. There is no way that it's "included" when you buy a housing, it'll be a separate part that you have to buy.

As a corollary to that, I think you're making an incorrect assumption thinking that the sensor was changed when the housing was changed at xmas. I'd say it probably wasn't.

Ok, fair point on the thermostat! I'm still gonna pick up my 'freebie' though and will go from there.

RE the sensor - I'm pretty sure it is included in the housing cos I changed it myself when it was done and if the sensor wasn't there I would have had nowhere to plug in the cable right?! :confused:

I've been looking for a pic to describe it but the nearest I can find is Simonize' comments in this thread:

http://briskoda.net/favorit-felicia-fun-forman/felicia-intermittently-cuts-out/58356/

Still I think a new sensor is in order. Where's best for that? Are the Jorily ones good?

Off topic - I googled 'Felicia Haynes' and was directed to someone's Facebook page - poor lass!

at least the lambda probes on these aren't too expensive

ebay link £35 off ebay

cant really add to much to this thread other than to echo what djay has said. that the lambda probe only actaully does anything to the fueling at light/part throttle, most of the time particularly under heavy load it runs open loop

RE the sensor - I'm pretty sure it is included in the housing cos I changed it myself when it was done and if the sensor wasn't there I would have had nowhere to plug in the cable right?! :confused:

Not really - I've only fitted the Jorily kit, and that is only one half of the housing; the other plastic bit that fits to the head (via 2 M8 studs) isn't replaced; you unscrew 3 Acme bolts that hold the two halves together, and there you go. The sensor is fixed into the bit that bolts to the head.

Here's the housing:

You can see the three bolt holes.

I've just taken a pic of my one:

Blue bit is the bit that isn't replaced (and you can see the temperature sender in it), red bit is the new thermostat. Wiring on mine is different, but you should get the gist.

Thanks again for the messages

I've just picked up my freebie replacement thermostat and housing. djaychela - thanks for your pics - the official part includes both halves and therefore does include a new sensor as well, so will bang all that on to keep me going and then look at a replacing the sensor with a more reliable one, plus the Jorily thermostat.

Also picked up some new spark plugs as per your recommendation and checked with my Dad as to whether the Lambda has been changed anytime recently. He thought it may have been, so I'm gonna check through the service record for some confirmation.

Hopefully will get this done tomorrow and will post back with my progress.

Thanks for all your help guys - it's refreshing to find a forum where there's time for dumb questions - and I'm sure I have plenty of those up my sleeve!

It's only a "dumb question" if you ask the exact same thing several times. It may be a basic question to some of us, but it's never stupid to ask a basic question you've never been taught the answer to.

Yes. There are no dumb questions. Just dumb people. :eek:

Sorry for the bump - I meant to reply a couple of weeks ago but have been a bit busy. Anyway, changed the plugs, thermostat and housing and replaced the burst bit of hose and the car was much happier - warm starting problem gone, temp gauge reading ok, everything normal. I was gonna post a pic of the old plugs but have totally failed - they were just quite blackened but new ones in now I'm gonna obviously keep an eye on this and may go for the Jorily part as and when I have any spare dollars. So, thanks again for all your help. Please check out my new thread where I discuss the merits of a juddering steering column and loss of control whilst travelling at 80mph on the A34!!!