Cold start splutter for about 20-30 seconds!

Hi guys… got a small issue when i start my 1.8 GTI DX cabby… for a small time it's splutters.. once she's going it's fine, even after a small run it ticks over no problem..
i can hear the Air valve working by the left of the inlet… do you think it's my 5th injector not performing??? or is the warm up valve/regulator not working?  also when i 'pinch' the air flow it does splutter..

thanks guys..
Deandubya

Try unplugging the blue electrical connector for the 5th injector and then try starting it, if it's better you may have leaking injectors and when the 5th injectors adds more fuel to the petrol already leaked into the cyinders and it's running to rich.

oh man… hope that's not the case…
before i owned it i know that the injectors had work done on them only a few years ago… the info's in my receipt box at home… have to have a check, sure a compression  test was also done & the injectors replaced… common GTI fault when the injectors hit 100k..??

If they have been replaced for new ones then it could be something else which I hope it is, a compression test will not show if the injectors are faulty.
Take the spark plugs out as that tells you alot about how an engine is running and if you can get the mixture checked just to be sure, they check the mixture during an MOT so the details of that will be on the extra print out they some times give you at the garage?

my 1st set of injectors did about 120,000 miles and now my second set is giving up at 270,000 miles, I've had my car for 20 years and 200,000 miles so I know most of it's history!
(new rebuilt engine and new injectors going in over the next month or so)

Morning, tried the car last night with the 5th Inj. electric disconnected & just turned over… connected back up & she fired up straight away… so not the 5th Injector…
just out of the blue, i've got a small fuel filter fitted… not the large round ones, that wouldn't make a difference would it?
270k! that's pretty good going… well maintained by the sound of it  

doesnt sound right? pics?

Just checking you have the right bit, the 5th injector is on the end of the inlet manifold near the drivers side suspension turret it has a blue electrical connector and a braided fuel hose going to it and you only need to remove the electrical connection for it not to work, with the weather being warm at the moment the car should still start even without the 5th injector connected. As rubjonny says and pictures of the connections/engine bay?

There is an idle stability valve fitted so what could be happening that is having to work to keep the car running its only suppost to work when you put extra load to the engine when you turn on lights, blowers, heated rear screen etc not keep the car running from cold.
I expect the idle control screw has worked its way lose and tick over is to low so the idle control valve is keeping the car going, try increasing the idle on the screw once the car is hot to 950-1000 rpm, it's at the back of the throttle body near the bulk head 7mm spanner is what you need
There is a little o ring which sears and holds the screw in and they are know to perish over time.

Try that and let us know how you get on.

I don't know much about the WUR as I've never had a problem with mine so I've not had to play with it or look for one and Yes its a rubber O ring on the idle control screw.

mark1gls - update… car went into garage, said they couldn't really notice any contamination in the tank, the filters were clean too (possibly as i used Wynns fuel/injector cleaner). 2 breather pipes were changed & i noticed an increase of about 6 or 7 mpg just on taking the car home. The garage boss asked the outcome of it & we had a little chat.. he wasn't happy that it wasn't running right from start-up so he's having it in on the weekend & going to give it a good tune & diagnostic check… all this while i'll be at Margam Volksfest So i hope to get it running sweet soon… keep you posted! have a good one.. 

Glad its slightly better but please let us know what they find/do so we all know for future reference.

What breather pipes did they change
Andy

thats fine, is just the late k-jet type smaller filter

I thought you meant you had some other random filter as well!

ah sorry, t'other way round! the wee one is the early type up to 84, then after that its big one:
http://www.vwspares.co.uk/g1filters.php

makes no odds either way just need a bigger jubilee clamp if you fit a fat one

nah as long as the filter isnt blocked its fine, will flow just the same either way

just to put your mind at rest, I had the pre-84 smally one on my mk1 cab 16v, and it was fine

andyphill mark1gls rubjonny
Morning, collected car from garage last night… basically he did various testing & only thing that it was is the 'cold starter valve' - 5th injector!!! he said that it's 'spot on with the mixture/timing/CO2's etc & running very nice' so i'm going to change the Injector, give the inlet man. a good clean out & see the outcome. (was planning tonight but weather's against me!) Do it tomorrow & update you on the outcome… 

What fuel are you using? Normal unleaded or super unleaded?

Dean, Good to see your making some progress. I will have to strip mine down and make sure everything is good and clean, I have a spare 5th injector so it will do no harm changing that to see if it makes any difference. Yours did look a little black around the edges, i wonder what it was like inside.
Andy

mark1gls said

Super unleaded is the best fuel to use on these cars so you are doing the right thing there, the 5th injectors only works from cold and only sprays a little fuel in there so it won't make any differeance once the engine is hot, I've had mine unplugged for about 9 months as my injectors leak so I've no need for extra fuel on start up as the car just runs lumpy on start up if the injector is plugged in and I've not noticed any difference in performance without it. I'm currently fitting a rebuilt engine and new injectors so I be able to plug it back in soon.

From “Cold start splutter for about 20-30 seconds! ”

Morning gents, hope you had a good weekend… (Haynes manual got delivered )) i had a bit of fun with the car… basically i disconnected a lot of the pipes around the inlet manifold etc, all around that area of the car… Aux air valve pipes, idle boost valve pipes, air regulator…
Got Wynns Carburettor cleaner from Halfords £6.99 (got a small white spray attachment for the nozzle) took off the 5th injector & the air inlet from the air meter as well, open the throttle valves & could see right through. Got a small bottle cleaner (brush thingy) to put in the inlet manifold, sprayed in there, & the brush, then tried to swirl it in the manifold inlet - as there's a lot of carbon build up - this i found with the air pipes etc as well!! it's surprising how much build up of carbon there is in the air pipes! with the Air valve i got the nozzle attachment & sprayed direct in the hole & gave it a shake as the cleaner thins stuff out… the plastics on the throttle body & air meter, sprayed & wiped & there is black stuff/dirt that comes off…
Started the car, it seemed better! took it for a small drive & it seemed smoother with pretty good mpg… hell of a lot less jumpy on start, less time as well! i will repeat this in the next few weeks to clear it as much as possible… definite signs of improvement!!!