Hot/warm starting problems mk1 Storm

[sanjay529]

Bit of a weird one. The car will start and drive fine for the first time of the day, and if you turn it off for a short time like a few mins it will start and run fine again. However, if you come back to it an hour or 2 later it will not start. It just keeps turning over and you can't hear the fuel pump running. I've tried messing with the relays, you can hear and feel them clicking on, but no pump. After a lot of trying, suddenly the pump starts working and the car starts fine again. I don't want to go changing things that don't need to be. I first thought it could be the pump relay, which would be an easy fix. Or could it be the fuel pump? Are either affected by being warmed up and then stop working? Or am I completely looking in the wrong place as both can work perfectly sometimes?

[ianaudia4]

You could try cleaning up the terminals on the fuel pump and checking the cables going to it, maybe just corrosion (hopefully!).

[sanjay529]

I did think it was the wiring, but its just too weird how I can replicate the problem almost identically each time when rotten terminals should be a permanent problem. Worked fine for a 15 min drive this afternoon, and started fine immediately a few times when I got there. Left it for a few hours, wouldn't start again. Messed with it for 30 mins and kept trying, gave up. Then thought one last try, and typically the pump kicked in and fired up fine! Drove home fine, started a few times fine after I got back. Left it for over an hour, now it doesn't start again. Bet its fine in the morning again. Pulling my hair out!

[PeteGLi]

Have you checked the plug into the back of the fusebox - Pin A8 - as it is prone to overloading and burning out. You may need to make up a variation of the factory fix, as the parts are no longer available.

[malmac]

Just stumbles across this thread, I have similar symptoms. I've got a mk1 scirocco gti, starts first time when cold, and when been stood for a short while but after an hour or so takes a while fire up again and when it does it doesnt fire on all 4 cylinders, it splutters for a few seconds then fine. The cars had recon injectors with new seals.

Anyone found any solutions/suggestions??

[jimmy h]

Could be the fifth injector (cold start valve) at the very end of the intake manifold.
Either weeping fuel after shut off, or coming on when it's not supposed to ie when hot giving you too rich a mixture.

[malmac]

The fifth injector doesn't work even when cold, unfortunately. I wonder if you're right and it comes on when it's warm, that would explain things, although that's far to easy a fix !!! That would mean faulty TTS i presume?

[jimmy h]

Hello Mal,

Got to admit I'm stabbing in the dark a bit here with remedy?

Will it start if you press down on the accelerator pedal in this situation? ie opening up the butterflies on the intake and giving the engine more air to see...
Easy to rule out by unplugging the plug to the fifth valve...

I've had a couple of mk two injected rocco's many moons ago and I seem to remember this was the issue - I could be wrong tho!

[malmac]

It eventually starts when warm when applying throttle yeah, then splutters for a couple of seconds, then fine.

Think i'll go with your easy fault finder and unplug 5th injector and simply see if problem persists.

thanks again.
Mal.