Hi I’m keen to hear others thoughts on this to help me work out what I need to look at.

 

GT 3f fuel pump primes and car runs fine once started. Just when cold and been sat longer than a day it doesn’t start after the first prime, normally 3 primes makes it start first time.

 

I've tested fuel pressure during the cold start, at idle and with vac off the FPR and it’s getting plenty pressure. It’s like it’s getting insufficient fuel after one prime. But then after second attempt it catches and runs fine. Fuel filter is 2 years old.
 

I have a spare FPR but before I start looking at fuel pumps and rates etc does anyone have any good ideas?  

Cold start needs a rich mixture and strong sparks to keep running.

There's cold viscous oil to pump around.

 

Simple things first. Air, fuel, spark.

When was air filter changed?

Fresh or stale fuel?

How old is the battery? How old are the sparkplugs?

 

Car kept in a garage or under a carport roof will be drier than one open to elements in damp weather.

^ he's saying it starts fine if you repeatedly prime the fuel pump via the key....not so if you go straight to cranking

 

none of the above would effect this ...its saying to me theres not enough fuel for the first crank 

Ah, okay.

The Lupo would run the tank pump when you opened the driver's door.

Took me ages to work out where the humming noise was from.

 

Is there a tank lift pump and an injection pump ?

Is there a fuel filter between the two that is partially blocked so lift pump

not doing much on first primes?

Edited 21 January, 20215 yr by dvderlm

i suggested the lift pump but the gauge flys around to 3 bar on 1 prime /try 

 

yes they have a lift pump , main pump and a replaceable filter 

Yes pressure checks out fine. Might just replace filter and FPR to see. But I’m guessing really. Something to do with lack of fuel, air in the line and not enough fuel going through during first start?

Is the pressure regulating valve holding the pressure on the injectors ? if it's not that could explain the poor starting

Thanks Nige, yes pressure test I did reads well against these values. 

Edited 23 January, 20215 yr by Bawbag

Just finishing this thread. Turns out pressure and fuel components are fine. I swapped out the ECU and the problem has gone.