Cold running problems

[AL_B]

OK. This isn't related to my S3, its relating to our AUQ engined (180bhp) Golf. But...I figured it would be ages before anyone would read it in the Volkswagen forum on this site, hence me putting the post here. Forgive me mods and Admins. /ubbthreads/images/graemlins/laugh.gif

When cold, for the first few handful of junctions etc., the car is very jerky, when setting off. Almost spluttery, but isn't spluttering. Its definitely not a misfiring coil-pack. Well not yet anyway. Its like kangarooing when you were a learner. I initially thought it was just the missus driving, but it does most of the time when the car is cold.

About 2-3 months ago, the engine check light came on, and we had the Coolant Temp Sensor changed under warranty. However, they botched the job, getting an unknown amount of coolant in the engine bay. Which they (warrington VW) got steam cleaned. Idiots.

My first thoughts on this problem are:-

1) Temp sensor, not fitted correctly?
2) Is it the green version?
3) Did they replace the O-Ring?
4) Did they put the correct amount of coolant back in the car? And was the coolant / water mix right?

How do I check the coolant mixture?
Where do I get coolant from?
How can I drain a bit of coolant out?

If its not the Temp Sensor, I'm thinking...

1) MAF...well did some logging last night, seems to be performing as it should, flowing 147 g/s, which is about 183bhp
2) Coil-packs and spark plugs

Is there anything else that you guys can think of that can cause this jerky cold running?

Cheers

AL

 

[AL_B]

[ QUOTE ]
How do I check the coolant mixture?

[/ QUOTE ]

Found some answers in the 4-cyl Turbo Engine Mechanics Manual.
Dealers should use VAG T10007 Refractometer for checking coolant mixture.
Only use coolant additive G 012 A8 D - meeting specification TL VW 774 D.
Upto -25degC, anti-freeze concentration should be 40%, so in a 5ltr system, that should be 2.0ltr of G12, and 3.0ltr of water. However 5ltr total may vary on Vehicle type.

[ QUOTE ]
How can I drain a bit of coolant out?


[/ QUOTE ]
Procedure is in 4-cyl Turbo Engine Mechanics Manual. But I don't think I will attempt it.

Could do with checking the concentration though.

Anyway, anyone got any ideas that isn't coolant related?

AL

 

[darnich]

a.Check the coolant level when the engine is completely cold, they might have put some coolant back but there might be some air trapped in the circuit
b.Only use coolant additive G12 - Do not mix with water
c.check coolant sensor again
d.You already know that but try unplugging the MAF sensor and see if it rolls any better

HTH

 

[Khufu]

my NA A3 did that but it was cured partially by the coolant temp sensor and later totally be the MAF.

Maybe they refitted the old one mistake LOL

We have a small telescope like thing that you put a drop of fluid in and sandwich between two layers of glass. The colour denotes the strengh.

 

[hamski]

I've just started experiencing the same thing. Almost a judder at low speeds. Thought it could be serious so I'm taking it to the garage on Friday. Will tell the mechanic your thoughts and let you know how it goes.

 

[DavidR]

My S3 did this from the day I picked it up from Glen until the day I handed it over to it's new owner.

It was subtle, certainly not something that shook my head about, but definately there and definately noticeable.

Cold starts for about 2 minutes or so.

Almost as if I was pressing the throttle up and down slightly.

No error codes and not affected by MAF / coilpacks / coolant temp sensor or performace map selected.

Mildly irritating, but I just ignored it in the end.

(BTW I'll move this to the VW forum shall I /ubbthreads/images/graemlins/tongue.gif )

 

[AL_B]

Thanks for the ideas guys.

hmmmm, don't know what to do really.

My view is when something just starts happening, out of the blue, when you know it didn't do it before, means there is a problem somewhere. And I just have to find out what it is. /ubbthreads/images/graemlins/smile.gif Bit difficult when its not my daily driver.

Khufu,

Where can I get one of these tester things from? Any ideas?


Think what I will do is:-

1) Check plugs and coil-packs, make sure they look ok, correctly gapped etc. Torque the plugs etc.
2) Check if the coolant temp is green one
3) Unplug MAF whilst, see if it runs smoother from cold.
4) Let car cool over night again, then log temps when engine is cold and gradually warming up. See if there are any wierd temp values recorded

If all that fails, it will have to go to the dealer.

Other than this jerkiness when cold, this is the best 1.8T engine I have ever driven. Its an absolute gem, smooth, good noise, instant throttle response. Much nicer than my S3's engine.

AL

 

[Khufu]

Dont suppose it could be the fuel pump. Bit sticky when cold, then freeing off a bit when it warms up a bit. I guess you could check for fuel pressure. Bit of a wild guess really. We used to have petrol pumps that did the opposite - seized when they warmed up (poor design)

Al, it came part of a pressure testing kit from Sykes and Pickering so I dont know where you'd get one from.

 

[AL_B]

Khufu,

Could be the fuel pump I guess, but its hard to tell. And hard to test...have you seen the manual?! /ubbthreads/images/graemlins/blush.gif I just don't have the tools to do it unfortunately. I can remember when I was down at AmD, when they were checking out my S3, I wanted them to check the fuel pressure and regulator and they talked their way out of it. A big job apparently, 2 hours minimum.

Anyway, back to our Golf.

Did some tests at the weekend. I logged coolant temp from engine cold, to 90degC, at idle. Temperature increase is smooth and gradual.

I also checked the plug torques, which were spot on. Didn't do plug gaps because I can't find my feeler guage. Coil packs are J's. There are hardly any misfires on cylinders. Car pulls very strongly. MAF reads 147 g/s regularly on full power, 3rd gear run.

I didn't get chance to run the car from cold with MAF unplugged. So thats the next test.

Anyone got any further suggestions?

Might do a throttle body adaption and test the O2 sensors. But I'm struggling to think what could be causing this problem.

AL

 

[Ess_Three]

[ QUOTE ]
My S3 did this from the day I picked it up from Glen until the day I handed it over to it's new owner.


[/ QUOTE ]

It did?

[ QUOTE ]

It was subtle, certainly not something that shook my head about, but definately there and definately noticeable.


[/ QUOTE ]

Gee...I must have other things to worry about...i never noticed...

 

[starski4578]

I have the same problem i just live with it now as no one can get to the bottom of it. Its fine as soon as it warms up. Ive had nearly all the temp and engine senors changed plus the maf but the cold starts is still a problem. No fault codes are brought up when testing. Sorry i cant help

 

[AL_B]

Thanks for the update anyway Starski.

These cars are a pain in the @rse.

AL

 

[darnich]

have you checked the lamda sensor?
the cat has to be hot in order to work properly-maybe it is something wrong there...

 

[benk]

Any chance that the throttle body is full of crap? That might restrict the valve and cause bad fuel control?

 

[AL_B]

Those are good suggestions guys. Thanks. I will have to check them.

AL

 

[HTC]

AL, my AUM engined golf just started doing this last week.

I've been through a load of checks and found the only thing thats out of place is the heating element for the post CAT lambda probe. Its showing no resistance indicating that the element is shot.

I'll be swapping it out at some point. I'll post my findings when done.

 

[AL_B]

Cheers HTC.

Our Golf is still the same. Didn't get chance to do anything with it this weekend.