Page 1 of 1
Warm Starting Issues
Posted: Fri Mar 10, 2023 6:08 pm
by hanna.melbo
Evening all!
I am having issues re-starting the car once the engine is up to normal operating temperature.
Cold starts are fine with no issues.
Warm starts are an issue.
When turning the key it seems to take an age to turn over once it has finished spluttering around before firing into life albeit rather gingerly.
Once it is running it seems fine.
Any ideas?
Any help is much appreciated!
Thanks in advance
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 6:46 pm
by mark1gls
Could be the non return valve on the main fuel pump or the accumulator.
Easy one to test is the accumulator, there is a little screw on the back of it, if you undo the screw and fuel leaks out the accumulator is shot, the seal inside it has perished as fuel is not meant to leak out.
I’ll post a picture of my leaking accumulator from the other week.
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 6:50 pm
by mark1gls
Mine would not stop leaking when I removed the screw so had to seal it up with some silicone till I could replace it.
It lives to the right of the main pump in the picture below.
Sent from my iPhone using Tapatalk
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 6:51 pm
by mark1gls
Forgot to add this just Fuel injection cars…
Sent from my iPhone using Tapatalk
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 6:55 pm
by mark1gls
Non return valve if needed, they also sell replacement hoses from the accumulator to fuel pump if needed?
https://www.classic-vw.co.uk/fuel-pump- ... 3453-p.asp
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 7:07 pm
by hanna.melbo
Brilliant, thank you! I will check tomorrow.
it is an injection model so this is very helpful.
The fuel pump was replaced recently (separate issue) and with it the non return valve.
What is the main purpose of the accumulator?
Re: Warm Starting Issues
Posted: Fri Mar 10, 2023 9:11 pm
by mark1gls
The accumulator hold the fuel pressure when you switch the engine off and when the engine is warm and you try and start it, the fuel pressure will still be there.
Video explaining it better than I can

about 3 mins in but worth watching if you want to know how the fuel injection system works.
https://www.youtube.com/watch?v=a4fJAfXYxWk
Re: Warm Starting Issues
Posted: Mon Mar 13, 2023 4:28 pm
by chopperoli
Do you have a pressure tester? Essential kit Leaky injectors is another possibility, if one injector drips after shutdown, the system loses its rest pressure and floods the engine enough to cause hard restart If it's neither that or what Mark said, then there is also a non return valve in the metering head which can leak down, it is part of the system pressure regulator plunger. You can get kits to replace the old o-rings on that thing and it is quite simple to do.
Re: Warm Starting Issues
Posted: Mon Mar 20, 2023 7:21 pm
by hanna.melbo
thanks Mark / Chopperoli. Fuel came out of the rear screw on the accumulator so i will replace this unit.
Its proving tricky to track down the correct one. It seems there are a load of different part numbers on the market, but confirming compatibility is proving tricky!
Re: Warm Starting Issues
Posted: Mon Mar 20, 2023 10:20 pm
by mark1gls
Most of them will fit as I brought a good 2nd hand one from a ford capri which is slightly longer and does not have the screw on the back but a tube to feed it back to the fuel tank so I fitted a small bit of hose and put a screw in the end, it works and was a lot cheaper than a new one..
https://www.ebay.co.uk/itm/334676953983 ... BM6LnJkeBh
Re: Warm Starting Issues
Posted: Mon Mar 20, 2023 10:25 pm
by mark1gls
I also had to replace a bit of fuel hose as mine would not come undone from the accumulator.
https://www.classic-vw.co.uk/mk1-golf-c ... 4343-p.asp
They also sell other hoses and an accumulator.