Octavia cold start problem

[Endre_]

Hi,

I own a 2000. Skoda Octavia 1.9TDi, 110hp.

From recently I have problems starting it in the morning.

The first start takes really long, and after that it starts normally

during the whole day.

I connected the car to VAG COM, and it showed that the Engine coolant temperature sensor is

faulty, so I replaced it, but the problem is still here.

When I measured the RPM of the starter with VAG COM, it showed that

the speed is 168 RPM.

I read somewhere that the normal RPM should be around 250.

Could this be the problem, and what could be causing it?

If you have any suggestions on how to fix this,

please help.

[pauldazzle]

250rpm is needed for correct cold start. Tired battery or starter motor are the usual culprits.

[Endre_]

The battery, and glow plugs are working fine.

So, it's probably the starter then?

What can I do to fix it, or must it be completely replaced?

[thesquiff]

Are you *sure* the battery is working fine? That's what I thought about mine until I replaced it and then all sniff of starting problems went away.

[Endre_]

I'm not 100% sure, I'll have to check tomorrow

morning, when the engine gets cold.

[Endre_]

Btw:

VAG COM reads the temperatures like this (it goes up to 8.5°).

Is this normal for a Mk1 Octavia?

[pauldazzle]

When up to normal operating temperature VCDS should be seeing about 88C.

[Endre_]

Here's the picture, sorry, the forum keeps logging me off for some reason.

[pauldazzle]

Coolant temp sensor is goosed if that's when engine is up to normal operating temp.

Edited 4 July, 2013 by pauldazzle

[Endre_]

Sorry, I don't know what "goosed" means. :-)

Btw, as I said, the sensor was replaced today with a new one,

but it still reports low temperatures.

(But the error in VAG COM is gone)

[pauldazzle]

Goosed = broken.

Did you fit a genuine VAG sensor?

[Endre_]

No, it's a "Beru", like the one from this link.

http://item.mobileweb.ebay.co.uk/viewitem?itemId=150733900082

[pauldazzle]

Mine & many other peoples experience with VAG engine sensors is buy cheap buy twice. MAF & CTS are prime examples of this. A genuine VAG CTS is about £25 so not an expensive part.

[pauldazzle]

For your information the ECU only throws a code if the CTS has gone open circuit or shorted to ground. If the ECU is getting a reading even if it's wrong it doesn't throw a code the same goes for the MAF.

[thesquiff]

Seen this so many times on this forum - only the genuine ones work.

[Endre_]

Well f***... :-)

The authorised services in my country do not sell original

parts, they only sell them if they install them themselves.

(For what they charge too much)

Well, I will have to order a new sensor online and check the battery, and the starter...

Btw:

When I started the car for the first time today, I stepped briefly on the gas pedal (while turning the key), and it started immediately.

Does anyone have an idea why?

Edited 5 July, 2013 by Endre_

[pauldazzle]

I would say the CTS is causing the ECU to fuel incorrectly, & giving it some gas pedal is helping start up.

[Endre_]

Is it possible that the CTS is slowing the starter down also?

Sorry about the repeating questions, but I want

to be sure what is causing the problem, before I order a new part.

[pauldazzle]

CTS will have no effect on starter rpm.

[hakangemini]

I have a problem on cold start up. At first few minutes idle rpm goes very low like 400-500 rpm suddenly and increases to 1300-1500rpm at gasoline. I have LPG installed on. When cold start with LPG there is no problem on idre rpm. But with gasoline i have. Motor works very jerky at first start for 2-3 minutes. Then prm goes normal levels (700-800 rpm). There is a log graph i took from vcds software from cold start.  sometimes press on gas pedal to see what will be the values and idle spped reaction after reaching higher rpms. Would some one can analyze and tell me what could be the problem?

 

The red is rpm, the green is motor coolant temp., the yellow is engine load, the gray one ise injection time, the mustard color is air mass amount, dark green one is throttle body angle, light blue one is lambda idle regulator value.

 

[gm73]

Would just like to add that my Octy Tdi had the exact same symptons as the OP and it was the timing causing the problem. Timing to the diesel pump had to be resert.