Diesel over reving at start up & idle?

Amy Popsicle

Hi,
Any advice would be much appreciated.

03 Skoda Octavia, 1.9.
Ive had this problem on and off for the last 6 weeks.
The engine is over reving on start up & in idle.? Often i get a power surge when driving. (almost feels like the turbo has kicked in twice ??)
However, on first start up at morning its running fine. The problem starts to surface after 2-3 miles of driving?
Also, it comes and goes. Sometimes 4-10 days gap between "problem".
No lights on dash and no smoke.
3 different garages suggested its the clutch? Im reluctant to agree with this as a new clutch went in 2 years ago.
Ive no problem changing gears. Clutch doesnt feel any different.

Any of you nice folks have any idea what the problem could be?

Thanks in advance

FirefighterT7

Amy Popsicle wrote: »

Hi,
Any advice would be much appreciated.

03 Skoda Octavia, 1.9.
Ive had this problem on and off for the last 6 weeks.
The engine is over reving on start up & in idle.? Often i get a power surge when driving. (almost feels like the turbo has kicked in twice ??)
However, on first start up at morning its running fine. The problem starts to surface after 2-3 miles of driving?
Also, it comes and goes. Sometimes 4-10 days gap between "problem".
No lights on dash and no smoke.
3 different garages suggested its the clutch? Im reluctant to agree with this as a new clutch went in 2 years ago.
Ive no problem changing gears. Clutch doesnt feel any different.

Any of you nice folks have any idea what the problem could be?

Thanks in advance

Possible EGR valve could be causing that..

jca

I'd say it's egr too.

Amy Popsicle

Thanks folks,
I had a feeling it might be that.
Garages see the blond coming and think im a cash machine.
I can do a DIY service, but think ill leave this job for the professionals.

FirefighterT7

Yep some can be a bit trigger happy if they see an opportunity, not just a blond thing , some places that can be a help not hinder ! It's a simple job to do I'm sure if you searched online you would find a video on how to do it.. It's only about 5 bolts to change..

Amy Popsicle

Yea i was having a look. I would be tempted, very tempted. But if i mess up, im with out a paddle in a creek if you get my drift.

s14driftking

My Passat simuluar engine as yours gave the same trouble I blocked of the egr valve 2 min job and it dosent do it as frequently.

The Real B-man

Or it could be the Camshaft Sensor does it rev up and down abit while idling? when driving does it drop power for a second or two then kick back in?

George Dalton

The usual reason for over revving on a hot start would be a faulty coolant temp sensor. A diagnostic scan should easily confirm either way.

Replacing an EGR valve or any other parts based on guesswork probably isn't going to work out too well.

Amy Popsicle

The problem still persists !
Various different garages all have different suggestions as to what the problem is. Im just not happy to fork out a wad load cash for a "process of elimination" repair.
The problem seems to come and go and this is part of the problem trying to get a definite diagnosis with a garage.

I have to add, the car is NOT driven every day. It is only used in and around the town. No more than 6-10 miles every other day. One garage suggested some sort of blockage as the car is not getting a "good run".

When driving, it gets a "surge" of acceleration without me hitting the accelerator?
It does seem to be lagging in power.
Its heavy on the diesel consumption.
When driving its running on higher reves than usual.
At idle it will either over rev and come back down in 1 second intervals,
Or,
It will slightly rev in quick rotation, almost feels like the car is about to cut out, but has never actually cut out.
And then i get 2-3 days were it drives fine with no problems?
Kids going back to school next week so it will be drove every day, 30+ miles. So i want it fixed and avoid having a brake down far away from home with cranky kids.

two wheels good

In a petrol engine I'd check the vacuum hoses - maybe a hose disconnected or cracked. Or an air leak on the inlet manifold.
Not sure if the same applies to diesel but maybe worth a look.

Amy Popsicle

Checked all the hoses. All looks good. Although there is a slight wear and tear on one, 99.9% its brakes related? Ill get a better look tomorrow.
Nothing ripped, cracked or leeking. Just looks a bit rough.
Couldn't see that being related to the problem though?

Ill eventually have to start getting work done to it.
Its an ego war now. Mechanics see me coming and think im a cash machine.
They are coming up with all kinds of sugestions with no real sense of "confirmation" of finding the fault. Whats bothering me most is that they say they could replace A,B and C with no guarantee that will solve the problem.
In other words they are gona screw me for as much labor and parts as possible.
Very frustrating.

exaisle

A scan with VAGCOM might reveal the problem.....preferably the full version rather than the freebie...

If any of the folks here have it, they might run a scan for ya if you ask nicely...it should only take 5 minutes....

Amy Popsicle

Any takers? Ill be nice. Honest!

Close to the square in Tallaght ��

exaisle

PM Sent