Rough starting

[Fabia_TDI]

Hi All,

Minor issue but I'm curious if anyone else has experienced this (or been able to improve it). First things first. 06 plate Fabia Elegance 1.9 TDi. When the car has been parked for a while (usually a day or more but sometimes as little as 8 hours) when I hop in and turn the key the engine sometimes seems to start with a nasty jolt and then idle a bit rough for a few seconds before settling down. Always starts first time though. Not running low on oil. Car is coming up for a service but even so - a bit odd. And if something needs flushing or cleaning I'd like to know what it is. I'm running a 9mm EGR gasket - no other mods. Engine is spledid the rest of the time.

Edit: Has only happened when cold but doesn't seem to bear any relation to how cold it is (e.g. 8 degrees - happened, 4 degrees - didn't).

[Chrispy]

Glow plugs or engine temp sensor I'd say. The engine does need to overfuel to do cold starts too so the temp sensor will be critical.

Try this on the next cold start, turn the ignition to Pos II but don't turn it over. Then turn the ignition off again. Then back to Pos II and off again. Do this a few times before actually starting the car and see if it helps. That's the method I used to diagnose dodgy glow plugs on my Pug 405 GLD.

If it doesn't help then my money's on a dodgy temp sensor.

When warm does it go ok on full chat?

[Fabia_TDI]

Thanks for that. Not noticed any issues when warm but if I'll pay attention and include them in my next post if I do.

[Chrispy]

Cool. Fuel flow issues normally show on cold starts and when flat out at high revs. If it's fine during the latter then I doubt flow is an issue.

[Fabia_TDI]

Key trick didn't make any difference when I tried it, although it seems to start perfectly well on it's own when it feels like it, even if it's cold. Weird. Annual service on Monday - I'll see if that changes anything.

[vindaloo]

Key trick didn't make any difference when I tried it, although it seems to start perfectly well on it's own when it feels like it, even if it's cold. Weird. Annual service on Monday - I'll see if that changes anything.

Mine's done the rough start trick once ever. Though I've recently had both the coolant and fuel temp sensors replaced and it happened in the interim "dodgy" period. Fingers crossed it won't do it again.

BTW: I live next to a river and most of its amusing little interludes and pining for attention moments have happened in the morning, first thing, starting up to go to work.

J.

[teedeeye]

I've experienced the same with my 143k mile PD100. During 2.5 years of ownership it's probably only done it say 20 times - and only when the temp is sub 5 degrees.

Mine will start - as you say, with a sudden jolt, but then proceeds to run faultlessly there-after. I do have a set of almost new glow plugs (salvaged from our scrapped works LT35 van) ready to fit, but to be honest it's never bothered me enough to warrent trying them.

PS, I start on the glow plugs on EVERY start-up - hot or cold.

[Zebra]

I have experienced the same on my 55 plate recently.

It has only happened when I changed from BP diesel to Jet diesel due to cost. I put it down to the car recognising the lower quality Jet diesel and making its ECU adjustments.

Now that the Jet has been running through it for a couple of weeks I don't experience it anymore.

If you do short trips I would check to see whether the EGR valve lifter is sticking due to the oily residue build up.

[Fabia_TDI]

Thanks for the info all. Nice to know I'm not alone. Doesn't bother me that much, the engine is lovely after 5 seconds. The dealer asked me if I wanted an engine flush when I had the service done and I said yes just to rule this out - I once ran a car that needed these once a year or so to stop the tappets sticking. No difference in this case.

No two PD engines are exactly the same are they? S'pose you have to smile

Edit: Mostly long journeys but I'll have a look at the EGR valve if I'm feeling mechanical enough.

Edit 2: Moisture - there's a variable I hadn't considered before. Hmm.

[Fabia_TDI]

Seems to be a bit better than it was (with no action taken) despite the weather being colder - I just leave the ignition on pos II for a second or two after the glow plug light goes out to make sure I'm nicely pre-heated. So at the moment I'm thinking it's probably not a fault (maybe paranoia). Thanks for all the education anyway.

[Dieselman]

It sounds like you may have a glow-plug failing. They don't always just fail, sometimes the heating coils short out so they don't get as hot.

My 'other car' has been chugging a bit on startup for about the last week and sure enough tonight a plug has gone.

I'll do it tomorrow but it's a bit annoying as they are only about six months old.