Problem start

Hi all, my a reg 1.8 gti has all of a sudden started not to start after normally one flick of the key. The only way I can get it to fire when cold is to release the main bolts on the metering head, filter and warm up reg, so bleeding it in effect. So when it does finally start it runs and drives fine but once warm and you turn it off and try to start it again it spits and splitters on the accelerator and if left longer then 5 mins that's it and it won't start at all and then I have to repeat what I do when it's cold. Has anybody had this problem or know what it might be please? Thanks Paul 

I had a similar problem and I messed around with a few bits but found that I changed the fuel pump actuator it now runs sweet, my one had accumulated lots of grit prob from the bottom of the tank, I am not majorly clued up as I am new to my golf but I was informed this is what is called by a friend it is number 9 in this picture 

Sounds like you got a pressure issue… there's 2 injector cables that are on your WUR or Warm Up Regulator, the left 1 is the return to the top of the Meter Head, it appears there's not enough pressure there, possible blockage. So is the WUR working? perhaps 1st an electrical test. Test the heating element, disconnect the harness connector & measure the resistance across the regulator terminals -Ohms, if there is an open circuit, no continuity, the WUR is broke. Also check the WUR is receiving Voltage, disconnect the harness connector & ground the coil wire! prevents engine start, when the starter is actuated there should be a minimum of 8V dc across the harness connector.
The WUR tells your system the pressure to the injectors & controls the fuel mixture on cold/warm start. Take off your WUR & check the gauze to see if there's any blockage there… The bolts are 13 & 14mm Left/Right. there will be a bit of fuel release from the inlet injector leads so be careful. The WUR to block 2 x Hex bolts are 5mm be careful when undoing these, apply a bit of Plus Gas to the joins.
Inspect the gauze.. see if there's anything on these… clean with an injector cleaner be very careful as the gauze are quite sensitive/brittle. May be an idea to clean out your injector inlet line & return as well… possible fuel filter change??? if there's been dirt inside… may be check your air flow sensor too. recommend CRC Air mass sensor spray for this as it doesn't 'stick' . If you take the sensor unit off look underneath the sensor plate for dirt & clean too with CRC & a cotton cloth.. - this a bit of a longer job, as the meter head has to come off via 2 screws & will involve adjusting the injector lines on the meter head to gain access - be careful for fuel release, keep a cloth underneath. If you take off the Sensor & Meter Head (FD) Check your gasket between the air box & sensor, cheap enough to renew if it's 'flat'. About £8 - £10. Also there's a rubber washer between/on the Meter Head/FD & the Sensor, if this is lose it needs to be renewed, there are 10mm bolts x6 between the air box & sensor. Check your air filter & housing/box for dirt & clean out.
When you have cleaned etc & put back together the 2 x Meter Head screws are hand tight with good pressure if you get my meaning. Meter Head/Injector bolts torque to 10NM, the WUR bolts - 13mm is 10NM & the 14mm is 20NM. the actual unit itself to the block is at least 10NM - if you renew & use Stainless bolts max would be 10NM.
There's also a PPR - Pressure regulator on the Meter head/FD, 16mm Bolt - be careful when taking this out, again fuel leak, along with a spring, there's 2 parts to this, 1 on the main bolt & a small 'head' which can sometimes not come out with the main part. Get a small screw driver to help this out, or if you got the FD off tilt it for it to come out, again be careful. Check the washers on both items for wear, this is a common occurrence of being worn & not being replaced so pressure being lost here. Also check the shim - the small flat washer below the spring, it should be about 1mm thick, you can add to this if it appears worn with small 0.' 'mm shims .3mm or .2mm… Again be careful in keeping clean all fuel involved parts - always.
When returning, tighten to 20NM.
The return injector that goes to the top of the Meter Head or FD via a 14mm CONNECTING BOLT be very careful of tightening of this, do this hand tight - i cannot stress enough if you take this out or disconnect.
Keep everything as clean as possible… Good luck dude…  It seems painstaking at the time but it's seriously worth it.


 

Thanks for your advice guys!  Much appreciated,I'll check everything you've advised and hopefully find the problem :-)