LPFP in the rear

[dennis10]

Just still tracking down my stumbling first cold start of the day in my ED30

The low pressure fuel pump, how much noise should it make when you open the door and/or prime with the key?  I think I can hear something very faint, but it's almost nothing - should it be pretty noticeable in the mk5?

[mjmallia]

Checked or replaced the HPFP cam follower recently?

Fuel filter change every two years?


You should hear the a faint pump noise for a couple of seconds then stop when the drivers door is used.

It will also prime on the key just prior to holding for ignition.

Have you tried double priming to see if that improves the cold start.  I noticed it helped on mine and discovered I had a leaking bleed back valve on the pump due to its age and miles. I got a genuine second hand one as a new genuine pump was £270 + VAT

The latest part number is 1K0919051DB and got one off a 1.4TSI Scirroco 2018 with low miles and 14 years younger for peanuts (£31) to give it a go.  I also discovered I had a pinched pump to tank seal from factory like a few other people

[mjmallia]

Thread here

https://www.mk5golfgti.co.uk/forum/index.php/topic,134529.msg1164972.html#msg1164972

[dennis10]

Checked or replaced the HPFP cam follower recently?

Fuel filter change every two years?


You should hear the a faint pump noise for a couple of seconds then stop when the drivers door is used.

It will also prime on the key just prior to holding for ignition.

Have you tried double priming to see if that improves the cold start.  I noticed it helped on mine and discovered I had a leaking bleed back valve on the pump due to its age and miles. I got a genuine second hand one as a new genuine pump was £270 + VAT

The latest part number is 1K0919051DB and got one off a 1.4TSI Scirroco 2018 with low miles and 14 years younger for peanuts (£31) to give it a go.  I also discovered I had a pinched pump to tank seal from factory like a few other people

Yep new cam follower, old one was fine, cam is fine.   New fuel filter too

I have a Citroen Berlingo 1.6 16v petrol that is very noticeable when it primes, both ignition and opening the door, but I don't have that in the GTI, but I don't have one to compare to so wasn't sure if the GTI was just quiet.  I can hear a very faint something, but nothing like in the Citroen.

Yes double priming helps - it doesn't always completely cure it, but it's much better after priming it beforehand than not.

I'll look towards the LPFP then - how did you find out yours had a faulty return valve - did you test with a multimeter?

[dennis10]

Just bought a used LP fuel pump from a 2013 VW Beetle 1.2 with the part number 1K0919051DB for just £20 - hopefully will fix the cold start for not much money!

[ZoliWorks]

Just still tracking down my stumbling first cold start of the day in my ED30

The low pressure fuel pump, how much noise should it make when you open the door and/or prime with the key?  I think I can hear something very faint, but it's almost nothing - should it be pretty noticeable in the mk5?

Any updates?


Gonna slide in with my 2 cents on the matter. So something funny I noticed over the past 2 years since I've had this issue, after every oil top-up or oilchange, the engine starts up right away for some time. The longer I go with the same oil, the worse my starts get. When the engine used up 1 liter and I filled it up with a fresh liter, my starts went back to normal.

I'm fairly certain I have piston ring issues cause the oil smells heavily of fuel. Way way more than my 1.4 which doesnt use any oil at all. Fuel thins out the oil which drops oil pressure significantly. Pair this up with an old engine that is notorious for oil pressure problems and I can see why the VVT would be misaligned/take some time to align, which explains the cold starts in a way.

These engines also have squirters under the pistons which are supposed to be closed and only open after a certain oil pressure/temperature. But overtime, they get stuck open permanently.


Then again, I could be entirely off. It's just speculation at this point.