Octavia vrs (mk1) struggles to start when cold

[Col200sx]

My vrs will struggle to start when cold. Even if left overnight the next morning will hesitate, try to fire up but not start.

 

But when I start it up and give the accelerater a small small bit of pressure it'll fire up ok.

 

It will also start every time when warm after that. It's just cold starts that it struggles.

 

The plugs and oem coils were replaced about 8k miles ago. Car is currently 141k on the clock.

 

Any ideas?

[Col200sx]

Ok to add further info to this.

 

I changed over to 4 Denso spark plugs I had spare, initially it felt better, but then yesterday, same cold start struggle again.

 

I've also tested the batter with a multi-meter. It got a reading of 12.2v from it.

 

And lastly in my service history I found that the throttle body has been taken out and cleaned about 50k ago.

 

Has anybody any suggestions?

[nitrovrs]

CTS (coolant temp sensor)?  Has it been on VCDS?

[Col200sx]

CTS (coolant temp sensor)?  Has it been on VCDS?

 

It had the timing belt and water pump replaced at a Skoda dealers a month ago. I asked him to give it a diagnostics check to see if there was any issues.

 

He checked it and said it was fine, no faults found at all.

[Ray Luxury-Yacht]

Ok to add further info to this.

 

I changed over to 4 Denso spark plugs I had spare, initially it felt better, but then yesterday, same cold start struggle again.

 

I've also tested the batter with a multi-meter. It got a reading of 12.2v from it.

 

And lastly in my service history I found that the throttle body has been taken out and cleaned about 50k ago.

 

Has anybody any suggestions?

 

How slowly / quickly does the engine actually turn over?

 

It could either be slow cranking, or a fault elsewhere.

 

Just to give you my 2p's worth on batteries as you've quoted a voltage:

 

It's generally accepted (do a search on the web) that a good, charged battery should show 12.6v - 12.7v at rest. This is after a load test too - i.e. the engine has been off for at least an hour, and then you give the battery a load for a couple of minutes (switch on the headlights etc.) then switch off the load, allow another couple of minutes, and then test the resting voltage. If it then shows 12.2v then either A: your multimeter is dodgy or B: in my opinion the battery is way past it's best.

 

Then when the engine is running, with a good alternator, you need to see at least 13.8v to 14.5v on the terminals. Again, anything lower than this points to a battery, wiring or alternator fault.

 

The other thing to mention is the dreaded fuse-box fault on these cars. On top of the battery there is a fuse-box assembly - check all the cabling and connectors here, they sometimes go bad, melt, and even catch fire!

 

HTH. Let us know how you get on my friend.

[nitrovrs]

It had the timing belt and water pump replaced at a Skoda dealers a month ago. I asked him to give it a diagnostics check to see if there was any issues.

 

He checked it and said it was fine, no faults found at all.

 

Diagnostic check may not show it if they only checked for fault codes, would check measuring block to highlight possible probs.

[darrylg]

Does the fuel pump prime the system when you open the door or turn the ignition half way?

[Col200sx]

How slowly / quickly does the engine actually turn over?

 

It could either be slow cranking, or a fault elsewhere.

 

Just to give you my 2p's worth on batteries as you've quoted a voltage:

 

It's generally accepted (do a search on the web) that a good, charged battery should show 12.6v - 12.7v at rest. This is after a load test too - i.e. the engine has been off for at least an hour, and then you give the battery a load for a couple of minutes (switch on the headlights etc.) then switch off the load, allow another couple of minutes, and then test the resting voltage. If it then shows 12.2v then either A: your multimeter is dodgy or B: in my opinion the battery is way past it's best.

 

Then when the engine is running, with a good alternator, you need to see at least 13.8v to 14.5v on the terminals. Again, anything lower than this points to a battery, wiring or alternator fault.

 

The other thing to mention is the dreaded fuse-box fault on these cars. On top of the battery there is a fuse-box assembly - check all the cabling and connectors here, they sometimes go bad, melt, and even catch fire!

 

HTH. Let us know how you get on my friend.

 

It took a couple of seconds to turn over, but with a bit of acceleration it fired up then.

 

I'll keep an eye on the battery. I may change it.

 

Diagnostic check may not show it if they only checked for fault codes, would check measuring block to highlight possible probs.

 

I had asked them to do a full diagnostics, they said they did and no errors. So maybe possible.

 

Does the fuel pump prime the system when you open the door or turn the ignition half way?

 

The fuel pump does prime when I open the drivers door, you can clearly hear it.

 

Also, I had a spare coolant temperature sensor, so I changed that there. It started up fine, and it hadn't been started in nearly 24 hours.

 

I also noticed that it got up to temperature way quicker than in the past.

 

I'll check again how it starts in the morning and report back again.

 

Thanks for the suggestions  : )

[Col200sx]

Ok today's update: It started fine from cold this morning, although still had the erratic idle for the first 45 seconds - 1 minute.

 

I tested the battery again while running and got a reading of 13.9v. So I'm happy the battery and alternator (replaced about 30k ago) are both ok.

 

I was going to clean out the throttle body, but have since read that you need vagcom to re-calibrate it. So the fact that it was done before, I'll leave it for now.

 

But next up in couple of days is to clean the MAF.

 

I cleaned one on my 200sx before with brake/carb cleaner, is this ok or do I need isopropyl alcohol cleaner specifically?

Edited 2 September, 2014 by Col200sx

[Liverpool-Lad]

You dont need to bother with VAG COM, just leave it plugged in.  With ignition on then you  can get someone to press the accelerator and clean the throttle body with a decent toothbrush and carb cleaner.

[Brit24]

Does the fuel pump prime the system when you open the door or turn the ignition half way?

ah I always wondered what that sound was when I opened the drivers door!! Really I was curious. Fuel pump priming. That's clever.

Thanks

[Ray Luxury-Yacht]

You dont need to bother with VAG COM, just leave it plugged in.  With ignition on then you  can get someone to press the accelerator and clean the throttle body with a decent toothbrush and carb cleaner.

 

Exactly this, done it on mine. Just don't unplug it and you'll be fine.

[Col200sx]

Ok back again with a similar update.

 

It's back to doing its cold hesitant start.

 

So I'm going cleaning out the MAF now.

 

Am I ok to use brake/carb cleaner? (I used this before on my AFM on my 200sx)

[Col200sx]

So having searched further and not being recommended to use brake/carb cleaner, I didn't bother cleaning it.

 

But having started it up and disconnecting the plug, the revs haven't changed whatsoever.

 

Tried it when cold and warmed up and the same. Does this look like my MAF is f.uck.ed?

 

Here's a video I took:

 

Edited 12 September, 2014 by Col200sx

[David 8]

That vid is marked as private !!

[Col200sx]

That vid is marked as private !!

Balls. I'll change it now. Thanks for the heads up.

 

Ok should work now:

 

Edited 12 September, 2014 by Col200sx