MK1 Golf GTI - Warm start problems

Yomp said

my motor has no problem starting from hot regardless of what fuel is in it. So what's the difference between mine and yours?

They shouldn't need super to start from hot. How do people in Ireland cope? You can't buy super in Ireland.
 

If my car had a problem it wouldnt start on the button every time. I have no idea why yours does start on the button when running 95 when its hot maybe you have a set of heat sheilds fitted round your exhaust.  The ur quattros also had hot start problems when unleaded was introduced & the audi gurus got round this problem by fitting blade type fan over the injectors that cool the braided lines down for a few mins after its stopped preventing vapour lock, when we moved over to electronic injectors vapour lock wasnt such a problem.
baz

I found the problem.

I had no returnvalve on my fuelfilter, which meant that my pressure inside the fuellines and fuel distributor fell instantly to 0 bar.

Now with a new returnvalve i have 2.5 bar for almost an hour.

Finally i got rid of this problem! Yay!

And now it wont start cold..   

check your injectors again for leaks, since you had no holding pressure there would be no pressure in them to leak past the injectors. but now you have lots of pressure they may now start leaking

Hi. I have been suffering exactly the same problem on my gti cabby. She starts from cold very well but as soon as shes warmed up and then left for ten minutes it will not go at all have to crank and crank with foot to the floor and it will eventually go but then fires on three for about 30 secs and then runs perfect and pulls like a train. I have changed the injectors for some decent low mileage ones, fuel pump, and the metering head plus fuel filter. The only thing i havent changed is the accumulator. I dont want to ,lash out 150 quid to find its the same unless I can diagnose it correctly first!

Did you manage to rectify the problem in the end w65 pirelli?

Hey

Yeah i did.

I fitted the accumulator but without luck.

Then i found out that i didnt have a returnvalve on the fuelfilter, which was why all the fuel pressure went back into the tank when engine was off.

Then my injectors were leaking like mad, i swap them around so that the worst were on the shortest fuel line and the best on the longest ones.

(Took them all out, made a rig for my air compressor and tested first with 1 bar when 1.2, 1.3 bar and so on undtil i saw bubbles in the fuel)

After all this i start OK on both cold and warm. My injectors can in some cases still act up, and only go on 3 cylinders in the first 5 seconds, but that is 1 out of 20. But they are cetainly up for a swap when i have the money for some new ones

My advice is to make a rig so you can meassure the hold pressure.

That can pretty much tell you everything.

the fuel pump should have a non-return valve which holds the pressure, on the accumulator there is a small screw on the back. if when you undo that fuel comes out you need a new accumulator (screw may be too rotten to shift mind)

i managed to sort my poor starting fault!! It was worse when warm. Finally removed the fuel pump and found the non return valve faulty. replaced the valve and now starts on the button hot and cold!! very happy, thanks for all the advice again chaps!