Hi all,

Last time you were all really helpful when I had a query about my 1.9 SDI, I now have a new issue and am hoping someone can point me in the right direction!

I am the proud owner of a 2001 Skoda Fabia 1.9 SDI with 30,000 on the clock. The issue is a little complex so bear with me while I try to explain as best I can!

Around 50% of the time the car starts normally:

1. Key in ignition

2. Glow plug light comes on for a second then goes out

3. Turn key to start and car fires up normally. Idle is just below 1000rpm (in the normal place for this engine)

4. Car runs fine.

5. When pulling away I rev to 1500 and pull off, nice and smooth

Ok so finally to the issue, the other 50% of the time:

1. Key in ignition

2. Glow plug light stays on for 10 seconds+ (In summer, not normal) then goes out eventually

3. Turn key to start and car fires up, revs roar to 3k+ for a split second then settle to idle at just under 1500 (too high)

4. When driving the revs stick at just under 1500 (you can hear they are higher as well as see it on the needle).

5. If I clutch up without accelerating the car pulls off at 1500 but jerks (bunny hops)

6. If I accelerate the revs rise higher than 1500 but pull off is smooth.

7. If I rev the engine in neutral it revs up but they always return to 1500.

8. There is no engine light on and it's not down on power at all.

9. While driving, after 5-10 minutes the idle suddenly corrects itself to just under 1000 (normal) and is fine for the rest if the journey.

When the glow plug light appears to be stuck on I have tried turning the key to start after 3 seconds ish and the glow plugs go out as soon as the engine is started but the problem still happens the same. I have no idea what the glow plugs sticking on has to do with the idle being too high?

When the glow plug light appears to be stuck on I have also turned the ignition off (glow plug light goes off) then turned it back on but the light still stays on for 10+ seconds or until the engine is started, then the problem happens the same.

I have noticed that if I drive the car hard, the next time I start the engine this is pretty much guaranteed to happen. If I drive it normally. The next time I start it there is a 50/50 chance it will do this. I'm thinking maybe a sticky valve or something?

Also (I think this is related) occasionally when in gear travelling down hill (using engine braking) the car will jerk forward as if I am quickly pressing and depressing the accelerator? This doesn't happen often though.

Any ideas guys? I'm not as familiar with diesels as petrols and am not sure where to look with this one!

Thanks in advance for any help.

Edited 2 July, 201411 yr by Mrrnoname

Fault code scan would be best option, but I suspect you have two issues.

1: Throttle pedal position sensor

2: Faulty glow plug(s)

How about the coolant temperature sensor?

 

not knowing much about diesels, surely the length of the glow plug "on time" is related to engine temperature? and as the coolant sensors tend to fail and are a cheap part, id say try it.

I had a problem where the faulty temperature sensor would sometimes case the temperature gauge to do odd things.

 

This manifested itself either as the temp gauge reading 1/4 scale too high.

 

Or as the temperature just going to zero on a hot engine.

 

Try that first its a 30 min fix.

 

The glow plugs should last nearly 100K miles

Hi All,

 

To complete this thread, The problem slowly became more and more common over the past year. Recently I finally got around to swapping the coolant temperature sensor. (15 minute job).

 

Even though the temperature gauge always started on 0 and smoothly rose to the middle position while driving, it was faulty. With the new sensor in place the problem has not happened once. 

 

When testing the coolant temperature sensor with a multi-meter. it's showing as open circuit for anything less than about 60 degrees, the replacement had a steady reading at any temp. So for anyone else who is suffering from similar symptoms (glow plugs staying on far too long and then a rising idle) try swapping the sensor. A Genuine one is about £40 from Skoda.

 

2: Faulty glow plug(s)

 

This problem would be noticeable only when starting the engine in cold weather.