Rough running at start up

[brianski]

Hi All

Has anyone come across this strange issue.

On cooler mornings when I start my car, a 2011 2.0ltr Superb Elegance 170 i have a big loss of power and really rough running like its running on three cylinders. If I try to rev the engine I hear a rattle coming from the back of the engine as far as I can tell.

This continues for a couple of miles then the car runs as sweet as a nut for the rest of day. There are no warning lights showing and no fault codes logged and worse of all it appears to be a bit of an intermittent issue.

Anybody got any ideas?

[FLAPPERJACK7]

Injector . Get the injector deviation values read. High values will be indicative of a faulty injector. Done a fair few with exact same symptoms.

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[lichfielddriver]

chuck a whole bottle of Forte diesel treatment in half a tank of fuel

 

[lichfielddriver]

BTW, the symptoms described are exactly the same I had in a Mondeo 130PS mk3 till i had the ECU updated at Fords

 

also, Swad diesels can remove and check an injector for about £35 and arent that far from you, nice drive out

[brianski]

Hi

 

thanks for the quick replies, I've tried a couple of injector cleaners but they didn't seem to have much of an effect although not tried Forte.

The car is in for a service this week so I'll mention the injector deviation values, but wouldn't they throw up a fault code if they were out?

[FLAPPERJACK7]

Not really. The ones I have fixed have no fault codes. A positive deviation value usually indicates the control plunger inside the injector nozzle is not fully closing. Ideally the values should be 0 but a plus of +3.00 would be a big problem. These values should be read whilst driving off from cold whilst having the symptoms at the same time. I would also have a compression check at the same time. Your engine should be 30 bar new with a wear limit of 20 bar.

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[lichfielddriver]

Have them out and checked on a test rig, the rigs are £40,000 but testing is a lot cheaper

 

Forte is £10......

[brianski]

Hi All

 

Quick update - car went in for a service and they data logged the injectors from cold, one injector had a value of +3.00 that settled down to normal after a couple of miles.

I'm now waiting for a quote for the cost to supply and fit a new injector unless there are any other solutions?

[danm]

Hi this sounds exactly like my problem, I also found it worse driving up hill, and it stopped if I took it off load by dipping the clutch, how much was the injector job in the end?

 

ta

 

d

 

 

[Pesmog]

A failed glow plug can also give the same effect on a cold start.  An engine will usually start with one plug not working and run rough initially and then recover.  The electronics won't always warn of a failed plug.     They are only about £15-20 each but can be tricky to change due to them having a habit of seizing in the head so best left to a garage.

Edited 24 January, 2016 by Pesmog

[danm]

Had my car checked 2 injectors were a fail - not out by loads, but not coding to the ECU properly, having 2 new ones fitted £185 ea. + diagnostics + testing costs - ouch,

 

Superb 2010 2.0 CR 140 Bosch injectors.

[FLAPPERJACK7]

A failed glow plug can also give the same effect on a cold start. An engine will usually start with one plug not working and run rough initially and then recover. The electronics won't always warn of a failed plug. They are only about £15-20 each but can be tricky to change due to them having a habit of seizing in the head so best left to a garage.

The glow plugs are inside the rocker cover inside the cylinder head and sprayed in the oil in this engine so seizures are not a problem on these engines.

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[danm]

2 new injectors fitted - so far no nasty noises/behaviour after 3 cold starts

 

Thomas fuel injection services - Blyth,  Northumberland.   seemed to know their stuff, nice guys, final bill £700 for diagnosis, removed all 4 injectors, cleaned and tested, then supply and fit 2 recon by Bosch injectors.

[Nedge68]

My Cr170 suffered this problem, it only occured when starting from cold in the morning (No warning lights), I took it to a Skoda garage who said it was probably due to contaminated fuel

the changed the fuelfilter (£60) and recommended I run it on premium fuel, rather than supermarket fuel.car was better briefly until the overnight temperatures dropped. So I took the car

for a TerraClean (£105) my car is now running as normal. I should say I did try running a bottle or 2 of injector cleaner but this didn't make any significant difference.