Diesel hot start - more news!

[Mr Music]

I've already posted a thread requesting help and posting outcomes for my 1.9 diesel starting problems.

(http://www.briskoda.net/forums/felicia-fun-forman/diesel-hot-start-problem/77545/?highlight=music)

However, I've just had the car serviced for the first time since buying it. The garage, Miller Motors in Torquay, is run by simply the most honest mechanic you will ever come across, Dave Miller. He is also fantastically knowledgeable, reliable and effective. He pointed out that there was a blockage in the fuel supply, probably just as a result of the car being eight years old. He changed the fuel filter and put an additive into the tank. It was, apparently, quite a job to get the fuel through after changing the filter. He recommended putting an additive in (I think he uses Comma) every three or four months to keep the injectors and fuel lines clean.

The bottom line is that the car is running much better than before, and I have gone back to the original green temperature sensor. The reason I needed the petrol one was that there was insufficient fuel coming through, so the fuel that was there needed the extra kick from the glow plug coming on. I mention in my other thread that the engine was making a curious noise, like pinking on a petrol engine, with the old sensor, and that the temperature was reading too high. Now it runs at a fraction under 90 degrees, as it should, and the noise has gone.

I guess the lesson is that, although replacing the correct diesel temperature sensor with the petrol one will work, it might be better in the long run to get the fuel system cleaned through, and to use an additive periodically. I'm rather looking forward to calculating the mpg from this current tankful, as I had only just filled up before taking the car into the garage. As it is running so much better (smoother, more torque, less noise) I reckon I might beat the 50 mpg mark. So far it returns 45-49 mpg, but never breaks the 50 barrier, and neither my wife nor I are speed freaks (well, you couldn't be in one of these, let's face it!).

Mr Music

[Alek Smart]

Hi Jeremy.

God bless Bono....Oops sorry I forgot....Gos IS Bono !!

Just read your post and I would thoroughly agree with its thrust.

In my case I had already worked through my Fuel System as it was my first port of call when the trouble began.

I am a time-served mechanic who spent his formative years working on the assorted products of the Leyland Motors Empire mainly Buses so the smell of diesel holds no fears for me.

My machine also has somewhat high Fuel Consumption which I am currently attempting to rectify.

I would be looking in this instance for tell-tale black smoke signs BUT I`m not getting any even under load !!

Perhaps the greatest single barrier to sorting everything is the fact that the Skoda is Mrs Smart`s Car......as long as it`s running it MUST be ok......Ok ?

Cheers.

[mutetourettes]

Hi - new to the forum as I've just bought a 99T felicia 1.9 diesel estate with 85k on it - looks like you're a friendly helpful bunch of folks!

I too have a green-banded temperature sensor and difficulty in warm-starting the engine (when the glow-plug light doesn't come on), so I've been reading through these various posts - I have some thoughts and a lot of confusion as to what might be going on:

I'm not sure if you're the only one who mentioned it but I also get the "pinking" noise whenever the engine is under load (ie i put my foot down, though it will rev freely in neutral fine).

My temperature on the dash gauge also reads pretty low, open road always a little above 70.

So this sounds like your original symptoms before getting replacement green sensor, thermostat and gasket. Did the "pinking" disappear when you changed these items and the temperature gauge read a happy 90?

you finally went back to the "original" green sensor - the one you had before you did any changing yes? so the sensor was fine to start with? if your thermostat was failing towards being open too much and the engine was being overcooled, the sensor would be right. an overcooled engine won't be running very well (?) (I guess an engine with fuel supply problems might also run too cool?)

The person who recommended a blue-banded temperature sender ( eg sea-kayaker, Pt No. 6UO 919 501 said he gets the glow plug light for a warm start - so I guess his (and Alek smart's) sender is reporting artificially slightly low temperatures to the DECU?

When you used a yellow-banded temperature sender your gauge read artificially high temperatures - does anyone have any idea why this would help the warm start situation? Surely it would tell the DECU "It's way hot in there, you don't need the plugs") Did you get the glow plug light during warm starts using the yellow sender?

Ideally i'd rather not just cut the temperature feed to the DECU, or feed it half truths!

d: So it seems that keeping all the lines clean with an additive will let the correct amount of fuel through, such that when your engine is warm the fuel/air mixture will ignite from pure compression, not needing the plugs, and the engine will respond in the way the DECU expects, without needing to be fooled that the engine is hotter/colder than it actually is...

at 79k my car had a new fuel filter and a Forte fuel flush (not sure if that's an additive or what at

[Mr Music]

Dear Mark,

For now, if I were in your position, I think I'd have a look for a sensor from the guys at Jorily if they still have one. The number of the part is as described in my previous post. Try this link for the Jorily shop:

eBay UK Shop - Jorily Skoda: Estelle Rapid, Favorit, Felicia

They are way cheaper than anyone else.

All of what you have written seems sound to me, but the finer workings of a diesel engine and its ECU are way ahead of me. All I know is, changing the sensor worked for me. I can find no mention of my cambelt being change in the service history, and it should be done at 60000 (we've done 72000) so I'm getting mine done next week. As far as I'm aware, there is no way of telling a worn belt until it breaks, at which point you throw the car away! At the service a couple of days ago they changed the alternator belt which was almost gone, so changing the cambelt is the obvious thing to do. Grit your teeth, pay the money and think of it as necessary insurance.

The pinking noise stopped after the service (it had increased with the new - incorrect but better functioning - sensor) so I still think that the whole issue of not starting, pinking noise, poor fuel consumption, smoking etc etc is down to a blocked fuel supply somewhere. Not enough to stop you going, but enough to bugger your about.

Good luck in all of this,

Mr Music (Jeremy)

[KenONeill]

I've been running diesels for years and years now, and never had issues with the MoT. But, and this is something a decent tester will do for you if you haven't done it in advance, in the couple of weeks running up to the test I put it right into the limiter for 4 or 5 s a few times. The idea being that knocks loose any loose soot in the exhaust that might burger up the test.