Not Starting when hot

Need help the Golf GTi has develope a hot start issue, it will start when cold no issue but after been driven for a few miles or more it will not restart until it's cooled down this can take up to an hour.

Hello mate, mine has had this exact same problem recently. I had a leaking fuel accumulator. Cold starts were no problem but once up to temperature it would just turn over but not fire. A previous owner had coated all my underneath with underseal & the leak was quite apparent where the leaking petrol had melted the underseal away.

Cheers I had the fuel pump off to fit a new cage. time to double check my work.

hi Jacob did you find out what the problem was with the hot starts, as i have the same problems
thanks

Interesting. 

I too have this problem but wa thinking more along the ignition route. 

Jacob, does your car start with a push/ bump start? Mine does so I was think possibly electrical. 

Dano, mine does but if you disconnect the cold start valve when the car is warm it will start straight away. Ive replaced almost everything and still cant find it. had to replace the tank due to a hole, pump, accumulator,fuel lines, cold start valve, ignition switch and full service. still head banging    

csv should only fire when the engien is cold, so that suggests a failed csv thermoswitch.

as for op problem this can also be down to a failed non-return valve in the fuel pump as well as faulty accumulator

rubjonny said

csv should only fire when the engien is cold, so that suggests a failed csv thermoswitch.

as for op problem this can also be down to a failed non-return valve in the fuel pump as well as faulty accumulator

Thanks  mate it it was the thermo time switch. Thanks to all others that commented

Are we saying to disconnect number 2 in the diagram next time the hot start, non firing issue occurs?? 

Ta.

yes you could try that, this should prevent the csv firing as the csv needs to earth via the thermoswitch in order to fire. if it doesnt help plug it back in and instead unplug the csv itself #4. if that helps then this suggests the green/white wire has shorted to ground somewhere

I found that if the car wasnt starting when hot . disconnecting plug number 2 worked for me.  If it does the same then change the thermo time switch. 

Thanks guys.

The green and white wire looks ok. It runs into the loom as it should without breaks but something could be breaking down inside I suppose. 

Dano what is the problem with your car mate

Starts on the key every time when cold. Starts at times when warm pretty much all the time but on occasions it fails to do so. 
There doesn't seem to be any pattern. In Germany Id pull up to the pumps to refuel and it would start, move off and park up for a 'comfort break' and on return it wouldn't start. Same again after the run back from Wolfsburg. After a 30 minute break to get changed it wouldn't start again. Before we even left for Germany I went to fill up, came home, parked and after 30 minutes its so went to set off and it didn't start!!! All I did was roll it backwards slightly and it started. Very strange. 

Ive replaced the battery and alternator - pre Germany. 

It will start in the bump start so I was thinking maybe ignition issues. The thing is, it's so adhoc I can't plan to be anywhere to check it over when it happens!!! 

When your having trouble starting the car from hot try unplugging the auxiliary air valve aka cold start valve. Number 4 on the diagram.  Sounds like the problem I was having which turned out to be the thermo time switch which is number 2. 

Undo number 4. Ok.

I'll try and remember to have a small screwdriver to flick the clip off… And a tissue to mop the undoubted blood that issue as a result of tinkering with the engine!!! 

doesnt sound like the csv/thermoswitch but more like a faulty non-return or fuel accumulator. but best to try unplugging csv/thermoswitch/aav first as they're free things to test

Is the non-return valve to with the fuel pipe? Lhasadreams mentioned that could be the problem. 

We've just not had the time to get together to test it. 
How do I know if the accumulator is faulty??? 

a good indicator is undo the little screw on the back of it (if you can!) if fuel comes out of it then it has gone and needs replacing. apart from that only way to test is with a set of fuel pressure gauges, or try a known good and see if it improves!

the non-return valve is the part the fuel line attaches to on the fuel pump, once the line is removed the non-return valve can be unscrewed. its also possible that the NR will unscrew itself if you try to undo the fuel line if the end nut is stuck

Thanks John.

I'll have a look at the manual and see what I can read up on. When the valve is unscrewed is fuel likely to flow out? An I best doing this with a low amount of fuel in the tank??