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Model specific boards => Golf mk2 => Topic started by: jazzygm on 10 August 2004, 11:30

Title: Cold start woes
Post by: jazzygm on 10 August 2004, 11:30
16V KR engine. used to start on the button every time. now... it doesnt! I put a post up in the garage section but got no replies!

I have to give it gas to start and it doesn't seem to auto-choke anymore (drops off and stalls unless I hold the rev's till its warm)

is this solely the cold start valve? or is it something worse?  :-\

my earlier thread about engine conversions, was of course not influenced by this problem at all....  ;) ::)
Title: Re:Cold start woes
Post by: tobz. on 10 August 2004, 12:10
Hi
I used to have similar problems with my mk2 16v sometimes it was a complete pain to start and you had to keep it on the starter for about 20seconds. I also experienced it stalling at junctions and it would generally be gutless until properly warmed-up.
If you were only experiencing starting problems I would suspect the cold-start valve. This valve is like a fifth injector which only operates for the first few seconds when the key is turned from cold (thus enrichening the mixture as a choke would in a carburettor system).
As you are having problems during the whole warm-up phase I would suspect the warm-up regulator (this can be found on the right-hand side of the block with a couple of fuel lines and an electrical connector).
This regulator lowers the fuel pressure during the warm-up phase. This in turn allow the air flow meter to rise easier which in turn allows more fuel to flow (again enrichening the mixture). The proper way to test the warm-up regulator would be to put a pressure gauge in your fuel line and see that the fuel pressure starts off low and rises as the engine warms up.
A new regulator is about ?80 and isn't a bad diy job.
Unfortunately I wrote my 16v off before I got round to replacing the regulator so I can't guarantee that this will solve the problem.

http://www.auto-solve.com/mech_inj.htm

I found this site very useful for understanding the fuel system.

Hope this helps

Toby
Title: Re:Cold start woes
Post by: tobz. on 10 August 2004, 12:22
Just found the original thread from when I was having my cold start/running problems, can't believe it was still lurking down there:

http://www.golfgtiforum.co.uk/index.php?board=7;action=display;threadid=1534;start=msg6569#msg6569

Might be some useful info in there for you.

Toby
Title: Re:Cold start woes
Post by: Gambit on 11 August 2004, 16:17
just check and see if the ISV buzzes with the ignition switched on

if it dont then the cold start wont operate either

90% of the time its simply the temp sender on the side of the head, usually a dirty or bad connection

if your temp gauge on the dash work then swap the 2 temp senders over and see if that works

red/green wire is the ISV/ColdStart
red/yellow wire is dash temp gauge

make sure they are a tight & clean fit, if the ISV loses the signal for a milli second then it will not work until the ignition is switched off and restarted